AARoads Forum

I saw this article in the Danbury, CT News-Times:

Traffic jams are a daily headache on I-84 in Newtown and other places where the highway goes from three lanes to two. It can be frustrating seeing a stretch of that third lane sit empty as motorists move over to the other two and wait ... and really frustrating when the stray car zips by you using every last inch of the lane that's disappearing before moving over and cutting in front of everyone else.
The etiquette around when, exactly, you are supposed to move over, can be tricky. Connecticut is an "early merge"  state, meaning you are supposed to move over as soon as you can after seeing signs saying that the lane you are in is going away.
But other states, including Minnesota and Kansas, have implemented an alternative approach favored by many traffic engineers, and Connecticut is considering using it for construction zones.
It's called the "zipper merge,"  and calls for drivers to wait to merge until their lane is almost closed and then take turns with the car in the open lane when merging over.
Kevin Nursick, a spokesman for the Connecticut Department of Transportation, said that the state has favored the "early merge"  bo prevent drivers from getting stuck in a lane that is about to close or angering the drivers who poked along in the open lane.
But the state may ask drivers to use the zipper merge in construction zones when two lanes go down to one. This would allow drivers to use all lanes for longer, preventing congestion.
"If everyone is paying attention and takes their turn, then you can really keep the traffic moving,"  Nursick said.
John Ivan, a civil and environmental engineering professor from the University of Connecticut who studies road safety, said he supports the zipper merge. When drivers wait to merge, the majority of drivers in the designated lane wait a long time, while drivers who merge late cut the line, he said. If drivers use the zipper merge, the wait times are even and the line is not as long.
"Then, because that queue doesn't extend as long, it's a bit safer as far as drivers being surprised by sudden stopped traffic,"  Ivan said.
Still, the state is only considering the zipper for construction zones, Nursick said. In other merging situations, the DOT feels that traffic is moving too fast to safely pull off the zipper merge.
"You don't want to be waiting on someone's good nature and getting in at the last minute,"  Nursick said.
And the zipper merge only works if everyone knows to use it, he said.
"We've all seen it where folks will streak down that lane before it comes to end only to bypass more traffic,"  Nursick said. "And what does that result in? That results in traffic congestion for folks that are following the rules."
http://www.newstimes.com/local/article/Connecticut-considers-zipper-merge-to-ease-9200459.php

The article has me annoyed, so the CTDOT doesn't favor the zipper merge?!  So then, what's the point of giving notice of a closed lane if you're not supposed to use the available lane? Might as well just have one sign and close the lane then.  lol

I know CT DOT is behind the times or stuck in their ways, but c'mon.  The DOT comments kind of surprised me actually.

I have definitely noticed issues with people who streak down the lane and cut in when everyone else is doing an early merge.  It causes everyone else to have to wait even longer so one selfish person can cut ahead.

As far as I'm concerned, ranked from best to worst:
-zipper merge
-early merging
-early merging with some jerks trying to cut in line

My problem with "early merging" is that if you have 50 drivers, you'll have 40 different opinions on where people should merge.

Quote from: 1995hoo on September 04, 2016, 05:03:06 PM
My problem with "early merging" is that if you have 50 drivers, you'll have 40 different opinions on where people should merge.

right and that's why I prefer zipper merging.  I just figured the DOT expected drivers to merge when the cones start to creep into the lane. 

But, unless there's a sign saying do a zipper merge, I don't see how it will ever be enforced.

There is a throughput limit of about 2000 vehicles per lane per hour. If there is more traffic than that, there will be a backup, zipper or early. If there is less traffic, there will be no backup, zipper or early. Even a short surge above 2k would create a backup.
Those who complain about "empty lane" and "inefficient use of space" are basically trying to kill a flock of birds with one stone. 

It's not a matter of strictly enforcing it...after all, people are still allowed to switch lanes if it's a passing zone. It's more important that people don't try to take matters in their own hands, such as trying to drive in both lanes, preventing one from pulling up in the lane to be closed.

Quote from: kalvado on September 04, 2016, 06:40:15 PM
There is a throughput limit of about 2000 vehicles per lane per hour. If there is more traffic than that, there will be a backup, zipper or early. If there is less traffic, there will be no backup, zipper or early. Even a short surge above 2k would create a backup.
Those who complain about "empty lane" and "inefficient use of space" are basically trying to kill a flock of birds with one stone. 

Also, such as what I came upon the other day...a stoppage in the work zone, due to moving equipment. Traffic didn't move for 10 minutes. Doesn't matter if you zipper early or not: traffic was completely stopped.

Quote from: Mergingtraffic on September 04, 2016, 10:54:00 AM
So then, what's the point of giving notice of a closed lane if you're not supposed to use the available lane? Might as well just have one sign and close the lane then.  lol

It's sort of a dilemma. On one hand, they're more or less required to give advanced warning of a lane-end scenario. But, they might have less early-merging if they didn't advertise the lane-ending at all. I think it's human nature to try and merge when you see the first "lane ends" sign, because you want to avoid A) being an asshole, or B) getting stuck later on because you passed on that gap 300 feet back. Thus, I'd prefer fewer lane ends sign. Two at most; one warning sign maybe 300 feet before the merge, and a final 'left' or 'right' black-on-yellow "merge" arrow where the lane physically starts merging. You certainly need to provide some warning, but some DOTs seem to go way overboard.

Quote from: kalvado on September 04, 2016, 06:40:15 PM
There is a throughput limit of about 2000 vehicles per lane per hour. If there is more traffic than that, there will be a backup, zipper or early. If there is less traffic, there will be no backup, zipper or early. Even a short surge above 2k would create a backup.
Those who complain about "empty lane" and "inefficient use of space" are basically trying to kill a flock of birds with one stone.

Sure, thats true... if there are no exits or entrances anywhere in the congested zone. As soon as you add some exits in, when you are preventing people from exiting by congestion in front of them, then you are creating an additional delays and a further backup by the number of cars that want to exit before the merge but cannot. If you have an entrance, it could be causing it to back up off the ramp creating congestion on another road by not using the available space, in addition to another zipper merge area not getting used so additional space getting wasted and further pushing traffic back.

Quote from: UCFKnights on September 04, 2016, 09:05:29 PM

Quote from: kalvado on September 04, 2016, 06:40:15 PM
There is a throughput limit of about 2000 vehicles per lane per hour. If there is more traffic than that, there will be a backup, zipper or early. If there is less traffic, there will be no backup, zipper or early. Even a short surge above 2k would create a backup.
Those who complain about "empty lane" and "inefficient use of space" are basically trying to kill a flock of birds with one stone.

Sure, thats true... if there are no exits or entrances anywhere in the congested zone. As soon as you add some exits in, when you are preventing people from exiting by congestion in front of them, then you are creating an additional delays and a further backup by the number of cars that want to exit before the merge but cannot. If you have an entrance, it could be causing it to back up off the ramp creating congestion on another road by not using the available space, in addition to another zipper merge area not getting used so additional space getting wasted and further pushing traffic back.

Which is true if traffic has to merge right. If merging left, it is exactly opposite to what you described.
Another undereducated-traffic-engineer style thought is that problems with entering-exiting traffic are more likely in dense urban areas with multiple alternatives. Pushing traffic away from commitment point is beneficial, since it encourages and enables traffic to use alternative roads, and eases  throughput-limited congestion.  :pan:

Zipper merging only works if you have two lanes merging into the middle, and then traffic moves where it needs to.  I hate the budgers so much, the ones who do it every day in non-construction zones

I've seen the zipper merges work very well when they're signed so everyone knows what you're supposed to do.  I can't remember which state or states did that well.  There were signs saying a lane is closed ahead, but to continue using both lanes to the merge point.  Signs indicated that lanes should alternate at the merge point.  Then there was also a big sign, right before the orange cones in one of the lanes, that indicated the merge point.

I could make an entire fleet out of the ships passing each other in the night in this thread.

I've said that NJ always seemed to be a late-merging state, keeping the travel lanes available as much as possible.  On a current construction project on 295 which closes lanes at night, the only advance warning of a lane closure is 1,000 feet ahead!  And by that point, you can see the flashing arrow anyway.  I've seen them use 1,500 foot warnings as the first warning quite often, but never just 1,000 feet ahead!

Quote from: jakeroot on September 05, 2016, 04:50:42 PM

Quote from: texaskdog on September 05, 2016, 03:52:32 PM
No, it causes people to think this is an acceptable behavior even when it is not a construction zone.  In rush hour all the good people get over early, and the jerks wait til the last second and jam in.

If everyone merged when they saw an open merge zone, the backup would be enormous. The only reason a lane drop-backup doesn't start 20 miles back, is because of those good Samaritans merging where the lane ends.

If there is little volume on the roads, then merging doesn't matter -- merging is only an issue because of too many people trying to squeeze into one lane. If there isn't a lot of people, there isn't a lot of squeezing.

This.  If early merging were taken to its logical conclusion (at the risk of argumentum ad absurdum), then things would work even better if everyone moved over five miles upstream of the lane closure.  Or, better yet, ten miles upstream.  Or, better yet, close the whole lane for its entire length.

The reason that lane is there in the first place is because traffic volume warrants it.  The less of the lane that gets used, the more over capacity the road becomes.  The main pitfall of the zipper merge is the possibility of people coming to the end of the usable lane and then coming to a dead stop because no one will let them over.  When that happens, everyone has to step on the brakes when the driver eventually moves in at 4 mph.  If people actually did what they're supposed to, which is take turns at the merge point, then that wouldn't happen.  Minnesota, IMO, does the signage right on this one:  "TAKE TURNS AT MERGE". 

My biggest beef with early merging is the vigilantes who think they're doing a public service by riding the center stripe and blocking everyone else from going around them (truckers seem to be the worst about this).  This is not helping safety, as it encourages road rage and shoulder riding.

Quote from: kphoger on September 20, 2016, 03:32:30 PM

This.  If early merging were taken to its logical conclusion (at the risk of argumentum ad absurdum), then things would work even better if everyone moved over five miles upstream of the lane closure.  Or, better yet, ten miles upstream.  Or, better yet, close the whole lane for its entire length.

You are confusing road with parking lot. Parking lot capacity in measured by square feet. Road throughput is not.

Quote
The reason that lane is there in the first place is because traffic volume warrants it.  The less of the lane that gets used, the more over capacity the road becomes. 

Throughput of the road is limited by the spot of  least throughput.
did you ever hear words "weakest link"? This is exactly the case.

Quote from: kalvado on September 20, 2016, 07:09:30 PM
Throughput of the road is limited by the spot of  least throughput.
did you ever hear words "weakest link"? This is exactly the case.

No shit. That's our point. The consensus by the morons in this thread seems to be that if you merge the moment you see a gap, there won't be a backup at the merge point. The only way to guarantee this not to be an issue, by their standards at least, is to completely close off the lane that ends, such that there simply is no opportunity to be in the lane that ends, hence, no merge. The problem is, that's fucking stupid: more lanes equal higher volume, period. A single lane of travel does not have an infinite vehicle-per-hour throughput. Cars still have to leave a reasonable gap, and the road still has a speed limit.

For example, If a single lane has a VPH throughput of 600 cars, three lanes have a throughput of 1800 cars. Now, this should be obvious, but it's a concept that seems to be ignored by those who merge early. Merging early does not increase the maximum efficiency of a lane -- that is determined by the speed limit, and the following distance of the cars in said lane.

Now, does a merge lower the maximum theoretical throughput of a lane? Of course. But sometimes, lanes have to end. And sometimes, you need multiple lanes to handle demand. It's a god damn balancing act, and there's no perfect solution here.

Quote from: jakeroot on September 20, 2016, 07:59:35 PM

Quote from: kalvado on September 20, 2016, 07:09:30 PM
Throughput of the road is limited by the spot of  least throughput.
did you ever hear words "weakest link"? This is exactly the case.

No shit. That's our point. The consensus by the morons in this thread seems to be that if you merge the moment you see a gap, there won't be a backup at the merge point. The only way to guarantee this not to be an issue, by their standards at least, is to completely close off the lane that ends, such that there simply is no opportunity to be in the lane that ends, hence, no merge. The problem is, that's fucking stupid: more lanes equal higher volume, period. A single lane of travel does not have an infinite vehicle-per-hour throughput. Cars still have to leave a reasonable gap, and the road still has a speed limit.

For example, If a single lane has a VPH throughput of 600 cars, three lanes have a throughput of 1800 cars. Now, this should be obvious, but it's a concept that seems to be ignored by those who merge early. Merging early does not increase the maximum efficiency of a lane -- that is determined by the speed limit, and the following distance of the cars in said lane.

Now, does a merge lower the maximum theoretical throughput of a lane? Of course. But sometimes, lanes have to end. And sometimes, you need multiple lanes to handle demand. It's a god damn balancing act, and there's no perfect solution here.

I thought most drivers know 2 second rule - that means lane throughput of 1800 VPH. That's OK, though, feel free to continue arguing. I hope that would help you to pass your license test.

Quote from: kalvado on September 20, 2016, 08:54:27 PM
I thought most drivers know 2 second rule - that means lane throughput of 1800 VPH.

Where did you come up with 1800? I pulled 600 VPH out of my ass, just as an example.

Quote from: kalvado on September 20, 2016, 08:54:27 PM
That's OK, though, feel free to continue arguing. I hope that would help you to pass your license test.

I don't how many times I've had to say this to you, but here I go again:

What?

Quote from: jakeroot on September 20, 2016, 09:09:01 PM

Quote from: kalvado on September 20, 2016, 08:54:27 PM
I thought most drivers know 2 second rule - that means lane throughput of 1800 VPH.

Where did you come up with 1800? I pulled 600 VPH out of my ass, just as an example.

Oh, out of your ass... You need to stop giving us your shit...

Quote from: kalvado on September 20, 2016, 09:23:32 PM

Quote from: jakeroot on September 20, 2016, 09:09:01 PM

Quote from: kalvado on September 20, 2016, 08:54:27 PM
I thought most drivers know 2 second rule - that means lane throughput of 1800 VPH.

Where did you come up with 1800? I pulled 600 VPH out of my ass, just as an example.

Oh, out of your ass... You need to stop giving us your shit...

WTF are you even talking about?????

Quote from: 1995hoo on September 20, 2016, 09:33:36 PM

Quote from: kalvado on September 20, 2016, 09:23:32 PM

Quote from: jakeroot on September 20, 2016, 09:09:01 PM

Quote from: kalvado on September 20, 2016, 08:54:27 PM
I thought most drivers know 2 second rule - that means lane throughput of 1800 VPH.

Where did you come up with 1800? I pulled 600 VPH out of my ass, just as an example.

Oh, out of your ass... You need to stop giving us your shit...

WTF are you even talking about?????

Did you ever think about role of "ass" in humans? One of the things is that output of gastrointestinal tract is located there.
Food you consume travels through gastrointestinal tract, substances your body need are absorbed -  and leftovers are ejected in a form of feces, commonly known as "shit". It comes from "anus", locates between buttocks  - area commonly known as "ass".
So looks like there is only one type of substance that jakeroot could  pull out of his ass..

This thread is hilarious.  People can't even agree on the function of a human ass. 

On a broader note, a merge is never an ideal situation.  It's something that has to happen, like a necessary evil.  You aren't going to find a way to make merges function in an ideal way, other than to take the cars away.
I see jakeroot's point.  In order to maximize the serviceability of the road with the merge, you utilize as many lanes as possible for as long as possible--so with that considered, early mergers compromise efficiency in a way that's easily avoidable.  In areas with dense traffic, merging at the last possible moment is an inevitability--maximizing lane usage when all of it is needed.  I will readily admit, though, that I try to be an early merger whenever possible...but this is only when traffic isn't so dense (LOS A, B, maybe C).  If the traffic flow upstream of the merge exceeds the peak flow of the downstream segment with fewer lanes, merging creates a shock of slowness which resolves once the traffic recovers to the peak flow of those fewer lanes.  Early merging just shifts that shock of slowness to a slightly earlier time, or extends the period of that slowness.  Does this extension of the slowness also slightly reduce its intensity (if that makes any sense), so that the early merge is worth it?  I'm not sure how early mergers would cause a WORSE delay overall...though I understand that their lane in particular would move slower than the lane that ends.

A lot of it comes down to the area that one lives in.  Here in NJ, late merging is almost necessary because of the traffic we have.  The other day, Rt. 55 approaching Rt. 42 was jammed for about 4 miles.  Do you have 2, 4 mile lanes of traffic, or one long 8 mile jam, including traversing thru 3 interchanges?  Around here, using all available lanes is not only common, but necessary.  In more rural areas where people aren't used to traffic jams, they probably want to get over a bit earlier.  And guaranteed, the ones using the open lane to the end are those used to more congested conditions!

Quote from: jeffandnicole on September 21, 2016, 06:17:33 AM
A lot of it comes down to the area that one lives in.  Here in NJ, late merging is almost necessary because of the traffic we have.  The other day, Rt. 55 approaching Rt. 42 was jammed for about 4 miles.  Do you have 2, 4 mile lanes of traffic, or one long 8 mile jam, including traversing thru 3 interchanges?  Around here, using all available lanes is not only common, but necessary.  In more rural areas where people aren't used to traffic jams, they probably want to get over a bit earlier.  And guaranteed, the ones using the open lane to the end are those used to more congested conditions!

Quick estimate gives 40-60 minutes worth of traffic in such backup.. I would say this qualifies as a parking lot!
And I would think at that point some active control measures - such as setting up detours - should start.. or there is no detour space as well?

Quote from: kalvado on September 20, 2016, 09:46:10 PM

Quote from: 1995hoo on September 20, 2016, 09:33:36 PM

Quote from: kalvado on September 20, 2016, 09:23:32 PM

Quote from: jakeroot on September 20, 2016, 09:09:01 PM

Quote from: kalvado on September 20, 2016, 08:54:27 PM
I thought most drivers know 2 second rule - that means lane throughput of 1800 VPH.

Where did you come up with 1800? I pulled 600 VPH out of my ass, just as an example.

Oh, out of your ass... You need to stop giving us your shit...

WTF are you even talking about?????

Did you ever think about role of "ass" in humans? One of the things is that output of gastrointestinal tract is located there.
Food you consume travels through gastrointestinal tract, substances your body need are absorbed -  and leftovers are ejected in a form of feces, commonly known as "shit". It comes from "anus", locates between buttocks  - area commonly known as "ass".
So looks like there is only one type of substance that jakeroot could  pull out of his ass..

I was reacting to your commentary having had nothing to do with the topic at hand and turning into pointless rude ranting. The so-called "two-second rule" had nothing to do with anything. Time for you to learn some manners.

Quote from: 1995hoo on September 21, 2016, 07:51:33 AM

Quote from: kalvado on September 20, 2016, 09:46:10 PM

Quote from: 1995hoo on September 20, 2016, 09:33:36 PM

Quote from: kalvado on September 20, 2016, 09:23:32 PM

Quote from: jakeroot on September 20, 2016, 09:09:01 PM

Quote from: kalvado on September 20, 2016, 08:54:27 PM
I thought most drivers know 2 second rule - that means lane throughput of 1800 VPH.

Where did you come up with 1800? I pulled 600 VPH out of my ass, just as an example.

Oh, out of your ass... You need to stop giving us your shit...

WTF are you even talking about?????

Did you ever think about role of "ass" in humans? One of the things is that output of gastrointestinal tract is located there.
Food you consume travels through gastrointestinal tract, substances your body need are absorbed -  and leftovers are ejected in a form of feces, commonly known as "shit". It comes from "anus", locates between buttocks  - area commonly known as "ass".
So looks like there is only one type of substance that jakeroot could  pull out of his ass..

I was reacting to your commentary having had nothing to do with the topic at hand and turning into pointless rude ranting. The so-called "two-second rule" had nothing to do with anything. Time for you to learn some manners.

Well, if you think about 2 seconds as being random number - maybe.
If you think about human drivers as being somewhat sane and modestly responsible, you may realize most people are not willing to go well below 2 seconds.
There are numerous studies on the subject, and they all produce similar dependences:
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fjliszka.github.io%2Fassets%2Fimg%2Ftraffic%2Fspeed_vs_flow.png&hash=b9046ec8918b9948f7c0747ee66fb2c0e150b164) (https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi478.photobucket.com%2Falbums%2Frr144%2Ftradephoric%2FTransportation%2520Pictures%2FRandom%2FWA-maxthroughput_zps45c99969.jpg&hash=507f696676876d5f28ee0dc56490e1f52d8f0637)


maximum flow rate on a highway is about 1800-2000, maybe 2100 vehicles per hour. It slightly depends on road conditions - like speed limit (speed of free flow, to be more precise), number of lanes etc. So  2 second rule looks like an extension of  typical driver behavior.
Try to push things beyond that - and traffic falls into congested flow.

I thought anyone having some modest interest in road and traffic related issues should have seen those graphs more than once.

Quote from: kalvado on September 21, 2016, 06:52:47 AM

Quote from: jeffandnicole on September 21, 2016, 06:17:33 AM
A lot of it comes down to the area that one lives in.  Here in NJ, late merging is almost necessary because of the traffic we have.  The other day, Rt. 55 approaching Rt. 42 was jammed for about 4 miles.  Do you have 2, 4 mile lanes of traffic, or one long 8 mile jam, including traversing thru 3 interchanges?  Around here, using all available lanes is not only common, but necessary.  In more rural areas where people aren't used to traffic jams, they probably want to get over a bit earlier.  And guaranteed, the ones using the open lane to the end are those used to more congested conditions!

Quick estimate gives 40-60 minutes worth of traffic in such backup.. I would say this qualifies as a parking lot!
And I would think at that point some active control measures - such as setting up detours - should start.. or there is no detour space as well?

Detours would simply jams up other roads, most of which are single lane roads that'll just jam up all the local traffic needlessly.  It was on the weekend, so it would take up resources and require overtime expenses.  In this particular case, it was a combination of shore traffic and rainy weather, and the jammed routes are relieving traffic from other heavily travelled highways already.  Not much that can be done about it.  People may grumble about the traffic, but it's just another normal day in paradise!

I think kalvado needs to drive on the roads on which I drive. I won't say people are engaged in NASCAR-style drafting. But I'd say people following the so-called "two-second rule" are the exception, not the rule.

Quote from: 1995hoo on September 21, 2016, 08:56:38 AM
I think kalvado needs to drive on the roads on which I drive. I won't say people are engaged in NASCAR-style drafting. But I'd say people following the so-called "two-second rule" are the exception, not the rule.

Give FHWA a call, they may learn something new. So far, they consider 1850 VPH as LOS F...

Quote from: kalvado on September 21, 2016, 08:41:37 AM
maximum flow rate on a highway is about 1800-2000, maybe 2100 vehicles per hour. It slightly depends on road conditions - like speed limit (speed of free flow, to be more precise), number of lanes etc.

Quote from: kalvado on September 21, 2016, 08:41:37 AM
slightly

:rofl:

But yeah...the lack of ability to see eye-to-eye may largely be dependent on a difference in driving environments...with rural roads that never approach max capacity, merging is an entirely different animal.  Roads with tighter traffic need different considerations.  But another thing I've been seeing is excessive speculation--making 100 assumptions leading to a conclusion, which is presumed to be way more solid than it actually is.  (40 to 60 minute backup?  Where do you get that?)

My main take on zipper merges-Zipper merges are great, but not enforceable.  A zipper merge is a product of drivers choosing to take turns--it is not a necessary result of building infrastructure that fosters them.  Preferences toward a zipper merge vary regionally, because they exist due to driver culture.  At a particular merge zone, you can put up signs and stripe lanes in a way that makes it ambiguous which lane ends and which continues, but that's not going to necessarily steer people's behavior toward taking turns like we learned in kindergarten.  I've only really seen signage and traffic control spelling out zipper merges in Maine, where there's never really any tight traffic.  I think agencies in more urbanized areas realize the futility of signs and striping instructing motorists to enact a zipper merge.

Quote from: paulthemapguy on September 21, 2016, 10:44:05 AM
I think agencies in more urbanized areas realize the futility of signs and striping instructing motorists to enact a zipper merge.

In more urbanized areas, it happens naturally.  There's no need for signage. 

Quote from: paulthemapguy on September 21, 2016, 10:44:05 AM

Quote from: kalvado on September 21, 2016, 08:41:37 AM
maximum flow rate on a highway is about 1800-2000, maybe 2100 vehicles per hour. It slightly depends on road conditions - like speed limit (speed of free flow, to be more precise), number of lanes etc.

Quote from: kalvado on September 21, 2016, 08:41:37 AM
slightly

:rofl:

But yeah...the lack of ability to see eye-to-eye may largely be dependent on a difference in driving environments...with rural roads that never approach max capacity, merging is an entirely different animal.  Roads with tighter traffic need different considerations.  But another thing I've been seeing is excessive speculation--making 100 assumptions leading to a conclusion, which is presumed to be way more solid than it actually is.  (40 to 60 minute backup?  Where do you get that?)

My main take on zipper merges-Zipper merges are great, but not enforceable.  A zipper merge is a product of drivers choosing to take turns--it is not a necessary result of building infrastructure that fosters them.  Preferences toward a zipper merge vary regionally, because they exist due to driver culture.  At a particular merge zone, you can put up signs and stripe lanes in a way that makes it ambiguous which lane ends and which continues, but that's not going to necessarily steer people's behavior toward taking turns like we learned in kindergarten.  I've only really seen signage and traffic control spelling out zipper merges in Maine, where there's never really any tight traffic.  I think agencies in more urbanized areas realize the futility of signs and striping instructing motorists to enact a zipper merge.

Well, if you noticed - jeffandnicole was describing a specific situation observed at specific time: 4 miles of backup on a 2-lane road. 8 lane-miles worth of cars.  A middle school student would be able to estimate how many cars are there (google average car length, assume certain gaps between cars),  and well - throughput of remaining lane on the order of 1.2-1.5 kVPH would give an estimate of waiting time.
So which exact assumption you think is random? They are not accurate, but they give me an idea of what was going on. And - which I find more useful - they give me some idea of how traffic irregularities are handled and can be handled in NJ.

Oh, and 1.8-2.1 kVPH is for a highway stretch, no merges.

Any more questions?

Quote from: jakeroot on September 20, 2016, 07:59:35 PM

Quote from: kalvado on September 20, 2016, 07:09:30 PM
Throughput of the road is limited by the spot of  least throughput.
did you ever hear words "weakest link"? This is exactly the case.

No shit. That's our point. The consensus by the morons in this thread seems to be that if you merge the moment you see a gap, there won't be a backup at the merge point. The only way to guarantee this not to be an issue, by their standards at least, is to completely close off the lane that ends, such that there simply is no opportunity to be in the lane that ends, hence, no merge. The problem is, that's fucking stupid: more lanes equal higher volume, period. A single lane of travel does not have an infinite vehicle-per-hour throughput. Cars still have to leave a reasonable gap, and the road still has a speed limit.

For example, If a single lane has a VPH throughput of 600 cars, three lanes have a throughput of 1800 cars. Now, this should be obvious, but it's a concept that seems to be ignored by those who merge early. Merging early does not increase the maximum efficiency of a lane -- that is determined by the speed limit, and the following distance of the cars in said lane.

Now, does a merge lower the maximum theoretical throughput of a lane? Of course. But sometimes, lanes have to end. And sometimes, you need multiple lanes to handle demand. It's a god damn balancing act, and there's no perfect solution here.

It's a judgement call, balancing finding the gap with not using the not-ending lane unnecessarily.  It takes awareness of traffic patterns and the cars on the road, both ahead and behind.  It requires one to find a gap large enough to move over and match the speed of traffic in the other lane such that the traffic already there is not affected.  A person unable to do this shouldn't be allowed to drive.

I tend to find that approaching the merge is where the big slowdowns are, not when the lane has ended.  Once the lane has ended, traffic generally gets up to speed - not as fast as freeflow, but generally a respectable amount.  Approaching the merge can be a parking lot, because invariably someone uses "late merging" not to take turns but instead to pass a bunch of people and force everyone else to stop (often literally) and let them in.

Quote from: kalvado on September 21, 2016, 11:40:27 AM

Quote from: paulthemapguy on September 21, 2016, 10:44:05 AM

Quote from: kalvado on September 21, 2016, 08:41:37 AM
maximum flow rate on a highway is about 1800-2000, maybe 2100 vehicles per hour. It slightly depends on road conditions - like speed limit (speed of free flow, to be more precise), number of lanes etc.

Quote from: kalvado on September 21, 2016, 08:41:37 AM
slightly

:rofl:

But yeah...the lack of ability to see eye-to-eye may largely be dependent on a difference in driving environments...with rural roads that never approach max capacity, merging is an entirely different animal.  Roads with tighter traffic need different considerations.  But another thing I've been seeing is excessive speculation--making 100 assumptions leading to a conclusion, which is presumed to be way more solid than it actually is.  (40 to 60 minute backup?  Where do you get that?)

My main take on zipper merges-Zipper merges are great, but not enforceable.  A zipper merge is a product of drivers choosing to take turns--it is not a necessary result of building infrastructure that fosters them.  Preferences toward a zipper merge vary regionally, because they exist due to driver culture.  At a particular merge zone, you can put up signs and stripe lanes in a way that makes it ambiguous which lane ends and which continues, but that's not going to necessarily steer people's behavior toward taking turns like we learned in kindergarten.  I've only really seen signage and traffic control spelling out zipper merges in Maine, where there's never really any tight traffic.  I think agencies in more urbanized areas realize the futility of signs and striping instructing motorists to enact a zipper merge.

Well, if you noticed - jeffandnicole was describing a specific situation observed at specific time: 4 miles of backup on a 2-lane road. 8 lane-miles worth of cars.  A middle school student would be able to estimate how many cars are there (google average car length, assume certain gaps between cars),  and well - throughput of remaining lane on the order of 1.2-1.5 kVPH would give an estimate of waiting time.
So which exact assumption you think is random? They are not accurate, but they give me an idea of what was going on. And - which I find more useful - they give me some idea of how traffic irregularities are handled and can be handled in NJ.

Oh, and 1.8-2.1 kVPH is for a highway stretch, no merges.

Any more questions?

I didn't sit in the jam, but I drove over part of it.  For a 4 mile backup in this location with the conditions present, it's probably pretty accurate.

Quote from: vdeane on September 21, 2016, 01:00:28 PM
Approaching the merge can be a parking lot, because invariably someone uses "late merging" not to take turns but instead to pass a bunch of people and force everyone else to stop (often literally) and let them in.

Sigh.

People have to merge somewhere, Valerie. They can't all merge early. The earlier people merge, the longer the backup gets.

Quote from: jakeroot on September 21, 2016, 06:26:46 PM

Quote from: vdeane on September 21, 2016, 01:00:28 PM
Approaching the merge can be a parking lot, because invariably someone uses "late merging" not to take turns but instead to pass a bunch of people and force everyone else to stop (often literally) and let them in.

Sigh.

People have to merge somewhere, Valerie. They can't all merge early. The earlier people merge, the longer the backup gets.

Longer in terms of what? And when and why that matters? So far, the only argument I can buy so far is extension of backup into exit/interchange. Even then, backup must be long-term parking lot to actually be an issue - and likely will extend into critical areas anyway after a while.

Quote from: kalvado on September 21, 2016, 06:55:12 PM

Quote from: jakeroot on September 21, 2016, 06:26:46 PM

Quote from: vdeane on September 21, 2016, 01:00:28 PM
Approaching the merge can be a parking lot, because invariably someone uses "late merging" not to take turns but instead to pass a bunch of people and force everyone else to stop (often literally) and let them in.

Sigh.

People have to merge somewhere, Valerie. They can't all merge early. The earlier people merge, the longer the backup gets.

Longer in terms of what? And when and why that matters? So far, the only argument I can buy so far is extension of backup into exit/interchange. Even then, backup must be long-term parking lot to actually be an issue - and likely will extend into critical areas anyway after a while.

Longer in terms of "more cars in one lane equals longer backup", assuming a reasonable following distance.

Quote from: jakeroot on September 21, 2016, 07:41:56 PM

Quote from: kalvado on September 21, 2016, 06:55:12 PM

Quote from: jakeroot on September 21, 2016, 06:26:46 PM

Quote from: vdeane on September 21, 2016, 01:00:28 PM
Approaching the merge can be a parking lot, because invariably someone uses "late merging" not to take turns but instead to pass a bunch of people and force everyone else to stop (often literally) and let them in.

Sigh.

People have to merge somewhere, Valerie. They can't all merge early. The earlier people merge, the longer the backup gets.

Longer in terms of what? And when and why that matters? So far, the only argument I can buy so far is extension of backup into exit/interchange. Even then, backup must be long-term parking lot to actually be an issue - and likely will extend into critical areas anyway after a while.

Longer in terms of "more cars in one lane equals longer backup", assuming a reasonable following distance.

So what?
Is it good? bad? doesn't really matter?  And why?

Oh I get it...let's try explaining it this way.
Say there's a merge, with a continuing lane and a terminating lane.  If people in the terminating lane merge earlier, the continuing lane ends up with a disproportionately large amount of traffic volume, making them subject to a worse traffic jam than if they all waited until the merge point and merged evenly.  Merging early results in a greater delay for those vehicles who end up in the continuing lane prior to the merge point, with these vehicles now comprising a greater proportion of traffic.  Greater proportion of traffic means greater delays due to jamming.  And I would assume that greater delays are bad, right?

Quote from: kalvado on September 21, 2016, 11:40:27 AM
Any more questions?

Quote from: jakeroot on September 05, 2016, 06:50:38 PM
Around OKC, there's plenty of afternoon rush along the 44 and the 35

/me twitches

Quote from: kalvado on September 21, 2016, 06:52:47 AM

Quote from: jeffandnicole on September 21, 2016, 06:17:33 AM
A lot of it comes down to the area that one lives in.  Here in NJ, late merging is almost necessary because of the traffic we have.  The other day, Rt. 55 approaching Rt. 42 was jammed for about 4 miles.  Do you have 2, 4 mile lanes of traffic, or one long 8 mile jam, including traversing thru 3 interchanges?  Around here, using all available lanes is not only common, but necessary.  In more rural areas where people aren't used to traffic jams, they probably want to get over a bit earlier.  And guaranteed, the ones using the open lane to the end are those used to more congested conditions!

Quick estimate gives 40-60 minutes worth of traffic in such backup.. I would say this qualifies as a parking lot!
And I would think at that point some active control measures - such as setting up detours - should start.. or there is no detour space as well?

After thinking about it last night, this statement shows the clear difference between those in rural areas where congestion is having to sit thru 2 traffic light cycles...and suburban/urban areas.

On my daily commute home, I will sit thru a 10 mile backup...on a GOOD day.  14 mile backups to the previous interchange aren't terribly uncommon.  The actual delay time isn't all that bad, maybe another 20 minutes thru this stretch because of how rush hour congestion works.  But it just goes to show that if a 4 mile backup makes one think an official detour is needed, I don't know what they would do in a 14 mile backup!

Occasionally there'll be small sections where you can get back up to the speed limit, and on unusual days you may even hit well above the speed limit.  But anymore, we just hope to slow down to a point where we're only losing 15 - 20 minutes due to congestion.

Quote from: paulthemapguy on September 21, 2016, 11:22:50 PM
Oh I get it...let's try explaining it this way.
Say there's a merge, with a continuing lane and a terminating lane.  If people in the terminating lane merge earlier, the continuing lane ends up with a disproportionately large amount of traffic volume, making them subject to a worse traffic jam than if they all waited until the merge point and merged evenly.  Merging early results in a greater delay for those vehicles who end up in the continuing lane prior to the merge point, with these vehicles now comprising a greater proportion of traffic.  Greater proportion of traffic means greater delays due to jamming.  And I would assume that greater delays are bad, right?

Quote from: kalvado on September 21, 2016, 11:40:27 AM
Any more questions?

Great! But wrong.
No, merging point does not affect wait time. Wait time depends on rate of arrival to a jam and rate of entrance into the problematic spot (assuming relatively free flow within remaining lane). You cannot change rate of arrival, and rate if entrance into the narrows is about same, likely higher for early merge. (Last statement is not very obvious, let's set it aside for now)
In simple words, if 60 cars arrive to the jam each minute but only 20 can proceed, your wait time will be increasing by 2 minutes for every minute of jam growth, no matter how they come to a stop.

Quote from: jeffandnicole on September 22, 2016, 06:11:09 AM

After thinking about it last night, this statement shows the clear difference between those in rural areas where congestion is having to sit thru 2 traffic light cycles...and suburban/urban areas.

On my daily commute home, I will sit thru a 10 mile backup...on a GOOD day.  14 mile backups to the previous interchange aren't terribly uncommon.  The actual delay time isn't all that bad, maybe another 20 minutes thru this stretch because of how rush hour congestion works.  But it just goes to show that if a 4 mile backup makes one think an official detour is needed, I don't know what they would do in a 14 mile backup!

Occasionally there'll be small sections where you can get back up to the speed limit, and on unusual days you may even hit well above the speed limit.  But anymore, we just hope to slow down to a point where we're only losing 15 - 20 minutes due to congestion.

Great point, actually.
But, if you will, there will be more about it in terms of growth of a jam.
I, maybe incorrectly, assume more or less steady flow of traffic. And 40 min jam is not just 40 min, it is an increase of, let's say, 20 min per hour. You seem to think about relatively short commute brust with some peak waiting time.

Beach traffic, from my perspective, should have longer period of high demand, and waiting time may end up growing until traffic starts diverting -e.g. when entrances become blocked.
But I am definitely in a group who believe that 2 light cycle wait is a beginning of a jam.

Quote from: kalvado on September 22, 2016, 06:40:11 AM

Quote from: jeffandnicole on September 22, 2016, 06:11:09 AM

After thinking about it last night, this statement shows the clear difference between those in rural areas where congestion is having to sit thru 2 traffic light cycles...and suburban/urban areas.

On my daily commute home, I will sit thru a 10 mile backup...on a GOOD day.  14 mile backups to the previous interchange aren't terribly uncommon.  The actual delay time isn't all that bad, maybe another 20 minutes thru this stretch because of how rush hour congestion works.  But it just goes to show that if a 4 mile backup makes one think an official detour is needed, I don't know what they would do in a 14 mile backup!

Occasionally there'll be small sections where you can get back up to the speed limit, and on unusual days you may even hit well above the speed limit.  But anymore, we just hope to slow down to a point where we're only losing 15 - 20 minutes due to congestion.

Great point, actually.
But, if you will, there will be more about it in terms of growth of a jam.
I, maybe incorrectly, assume more or less steady flow of traffic. And 40 min jam is not just 40 min, it is an increase of, let's say, 20 min per hour. You seem to think about relatively short commute brust with some peak waiting time.

Beach traffic, from my perspective, should have longer period of high demand, and waiting time may end up growing until traffic starts diverting -e.g. when entrances become blocked.

I've never seen entrances blocked to a highway that's otherwise open but jammed.  Even with a highway that's shut down due to a major accident it's extremely rare for entrances to be blocked.  About the only time an entrance is blocked is when there's a motorcade or some other security-type event going on.

Quote from: jakeroot on September 21, 2016, 07:41:56 PM

Quote from: kalvado on September 21, 2016, 06:55:12 PM

Quote from: jakeroot on September 21, 2016, 06:26:46 PM

Quote from: vdeane on September 21, 2016, 01:00:28 PM
Approaching the merge can be a parking lot, because invariably someone uses "late merging" not to take turns but instead to pass a bunch of people and force everyone else to stop (often literally) and let them in.

Sigh.

People have to merge somewhere, Valerie. They can't all merge early. The earlier people merge, the longer the backup gets.

Longer in terms of what? And when and why that matters? So far, the only argument I can buy so far is extension of backup into exit/interchange. Even then, backup must be long-term parking lot to actually be an issue - and likely will extend into critical areas anyway after a while.

Longer in terms of "more cars in one lane equals longer backup", assuming a reasonable following distance.

Why should there be a backup?  If people merge at any given time at speed, and into an appropriate gap (as long as others are following at a reasonable distance instead of tailgating), then there need be no real backup at whatever point the merge occurs.  The problem comes in, in that people tailgate, actively block others from merging, while others bull their way in.  This is the crappola that happens in Chicago on a daily basis.  It's not road design, it's asinine driver behavior.

Quote from: Brandon on September 22, 2016, 09:36:10 AM

Quote from: jakeroot on September 21, 2016, 07:41:56 PM

Quote from: kalvado on September 21, 2016, 06:55:12 PM

Quote from: jakeroot on September 21, 2016, 06:26:46 PM

Quote from: vdeane on September 21, 2016, 01:00:28 PM
Approaching the merge can be a parking lot, because invariably someone uses "late merging" not to take turns but instead to pass a bunch of people and force everyone else to stop (often literally) and let them in.

Sigh.

People have to merge somewhere, Valerie. They can't all merge early. The earlier people merge, the longer the backup gets.

Longer in terms of what? And when and why that matters? So far, the only argument I can buy so far is extension of backup into exit/interchange. Even then, backup must be long-term parking lot to actually be an issue - and likely will extend into critical areas anyway after a while.

Longer in terms of "more cars in one lane equals longer backup", assuming a reasonable following distance.

Why should there be a backup?  If people merge at any given time at speed, and into an appropriate gap (as long as others are following at a reasonable distance instead of tailgating), then there need be no real backup at whatever point the merge occurs.  The problem comes in, in that people tailgate, actively block others from merging, while others bull their way in.  This is the crappola that happens in Chicago on a daily basis.  It's not road design, it's asinine driver behavior.

The backup doesn't occur because people are merging...the backup is occurring because of a blockage further down the road.  In a recent case I many have mentioned, traffic was stopped in the construction zone due to work going on for a few minutes.  Traffic at the merge point can't go the speed limit if traffic is stopped.

Even if traffic was moving at speed, in order for everyone to have an appropriate distance prior to the merge, they would need 4 seconds between vehicles.  As they zipper in, then it would be 2 seconds between vehicles.

Quote from: jeffandnicole on September 22, 2016, 08:55:24 AM

Quote from: kalvado on September 22, 2016, 06:40:11 AM

Quote from: jeffandnicole on September 22, 2016, 06:11:09 AM

After thinking about it last night, this statement shows the clear difference between those in rural areas where congestion is having to sit thru 2 traffic light cycles...and suburban/urban areas.

On my daily commute home, I will sit thru a 10 mile backup...on a GOOD day.  14 mile backups to the previous interchange aren't terribly uncommon.  The actual delay time isn't all that bad, maybe another 20 minutes thru this stretch because of how rush hour congestion works.  But it just goes to show that if a 4 mile backup makes one think an official detour is needed, I don't know what they would do in a 14 mile backup!

Occasionally there'll be small sections where you can get back up to the speed limit, and on unusual days you may even hit well above the speed limit.  But anymore, we just hope to slow down to a point where we're only losing 15 - 20 minutes due to congestion.

Great point, actually.
But, if you will, there will be more about it in terms of growth of a jam.
I, maybe incorrectly, assume more or less steady flow of traffic. And 40 min jam is not just 40 min, it is an increase of, let's say, 20 min per hour. You seem to think about relatively short commute brust with some peak waiting time.

Beach traffic, from my perspective, should have longer period of high demand, and waiting time may end up growing until traffic starts diverting -e.g. when entrances become blocked.

I've never seen entrances blocked to a highway that's otherwise open but jammed.  Even with a highway that's shut down due to a major accident it's extremely rare for entrances to be blocked.  About the only time an entrance is blocked is when there's a motorcade or some other security-type event going on.

By "blocked" I mean "blocked by traffic", not "blocked by police officers"... I hope that makes more sense?

Quote from: jeffandnicole on September 22, 2016, 09:49:28 AM
The backup doesn't occur because people are merging...the backup is occurring because of a blockage further down the road.  In a recent case I many have mentioned, traffic was stopped in the construction zone due to work going on for a few minutes.  Traffic at the merge point can't go the speed limit if traffic is stopped.

Bullshit.  As soon as we're past the merge point around here, traffic speeds up.  The merge point IS the blockage point around Chicago.

Quote from: Brandon on September 22, 2016, 10:30:32 AM
Bullshit.  As soon as we're past the merge point around here, traffic speeds up.  The merge point IS the blockage point around Chicago.

Seconded. Anytime I've gone thru the Zoo Interchange construction zone zipper, traffic has sped up once we were out of the zipper.

Quote from: kalvado on September 22, 2016, 10:04:24 AM

Quote from: jeffandnicole on September 22, 2016, 08:55:24 AM

Quote from: kalvado on September 22, 2016, 06:40:11 AM

Quote from: jeffandnicole on September 22, 2016, 06:11:09 AM

After thinking about it last night, this statement shows the clear difference between those in rural areas where congestion is having to sit thru 2 traffic light cycles...and suburban/urban areas.

On my daily commute home, I will sit thru a 10 mile backup...on a GOOD day.  14 mile backups to the previous interchange aren't terribly uncommon.  The actual delay time isn't all that bad, maybe another 20 minutes thru this stretch because of how rush hour congestion works.  But it just goes to show that if a 4 mile backup makes one think an official detour is needed, I don't know what they would do in a 14 mile backup!

Occasionally there'll be small sections where you can get back up to the speed limit, and on unusual days you may even hit well above the speed limit.  But anymore, we just hope to slow down to a point where we're only losing 15 - 20 minutes due to congestion.

Great point, actually.
But, if you will, there will be more about it in terms of growth of a jam.
I, maybe incorrectly, assume more or less steady flow of traffic. And 40 min jam is not just 40 min, it is an increase of, let's say, 20 min per hour. You seem to think about relatively short commute brust with some peak waiting time.

Beach traffic, from my perspective, should have longer period of high demand, and waiting time may end up growing until traffic starts diverting -e.g. when entrances become blocked.

I've never seen entrances blocked to a highway that's otherwise open but jammed.  Even with a highway that's shut down due to a major accident it's extremely rare for entrances to be blocked.  About the only time an entrance is blocked is when there's a motorcade or some other security-type event going on.

By "blocked" I mean "blocked by traffic", not "blocked by police officers"... I hope that makes more sense?

Yeah...and that does happen a bit more often.  Although even then it depends.  If it's a movement like (for example) NJ 73 South to 295 South and 295 South to 73 South, that one is jammed so often that most people just naturally assume it's jammed due to regular traffic.  In other cases, a jam on the ramp would be more unusual, and you'll be seeing people back up off the ramp.  In extreme cases which doesn't happen often at all, you'll see people going the wrong way, off an on-ramp (and without any cop actually allowing them to do so!).

Quote from: DaBigE on September 22, 2016, 10:46:46 AM

Quote from: Brandon on September 22, 2016, 10:30:32 AM
Bullshit.  As soon as we're past the merge point around here, traffic speeds up.  The merge point IS the blockage point around Chicago.

Seconded. Anytime I've gone thru the Zoo Interchange construction zone zipper, traffic has sped up once we were out of the zipper.

So you guys go thru the merge zone 24 hours a day?  You guys have the vision of seeing conditions that exist at all times.

The only bullshit I see is that you're making numerous assumptions about traffic everywhere across the world.  What you need to do is sit above the construction zone to watch the entire thing develop.   "I went thru there on a Wednesday 3 weeks ago" doesn't qualify as knowing how these backups work.   All it takes is 86 year old Granny Thompson to drive 25 mph thru that construction zone 15 minutes ago to bottleneck everything up.

I don't think there is any question around what to do when traffic is light:  merge over as soon as possible. But there is no adverse impact to when you merge, as long as you're not cutting someone off in the process at the last minute.  Besides the etiquette, that tends to slow down that person.

The arguments seems to be over what to do when traffic is heavy.  To that, here is the question:  is there any benefit to leave the closed lane empty by suggesting that the majority of people merge over early?  Om heavy traffic, a jam is going to exist whether everyone merges at the merge point, or if the majority of people merge early.

To me, the ideal situation is in heavy traffic everyone uses all lanes to the merge point, and then alternate. BUT...that only works if everyone alternates.  The second one person jumps their turn, this breaks down...but I don't see how the early merge solves this either.  Merging earlier might improve throughput at the merge point, but is negatively impacted at the earlier merge point.

Short answer:  is one really significantly better than the other?  Or are both no wins...when you factor in actual driver behavior? 

Quote from: jeffandnicole on September 22, 2016, 11:00:32 AM

Quote from: DaBigE on September 22, 2016, 10:46:46 AM

Quote from: Brandon on September 22, 2016, 10:30:32 AM
Bullshit.  As soon as we're past the merge point around here, traffic speeds up.  The merge point IS the blockage point around Chicago.

Seconded. Anytime I've gone thru the Zoo Interchange construction zone zipper, traffic has sped up once we were out of the zipper.

So you guys go thru the merge zone 24 hours a day?  You guys have the vision of seeing conditions that exist at all times.

The only bullshit I see is that you're making numerous assumptions about traffic everywhere across the world.  What you need to do is sit above the construction zone to watch the entire thing develop.   "I went thru there on a Wednesday 3 weeks ago" doesn't qualify as knowing how these backups work.   All it takes is 86 year old Granny Thompson to drive 25 mph thru that construction zone 15 minutes ago to bottleneck everything up.

You don't have to go thru it 24 hours a day to figure it out. We know it. The regular drivers of the corridor know it. WisDOT knows it, otherwise they wouldn't have put up all of the dynamic warning signs regarding stopped/congested traffic, UPSTREAM of the merge. Ever watch material travel thru a funnel? An hourglass? It speeds up past the point of narrowing. Just as jemacedo09 says, it's when traffic is heavy that the merge point becomes the issue. What traffic is doing at 2:30 am isn't the focus, because it doesn't matter where you merge with traffic being so light.

Quote from: jemacedo9 on September 22, 2016, 11:17:42 AM
Short answer:  is one really significantly better than the other?  Or are both no wins...when you factor in actual driver behavior?

My bet is that early merge is very slightly better in terms of throughput in case of light backups; but both are necessary evil, and both work equally... to the extent things can work - and both work  a little bit better when everyone is on the same page.
Late merge reduces/postpones propagation of backup into road access points, and as such may lead to slight increase of total wait time - assuming detours with ample capacity are available.

Quote from: DaBigE on September 22, 2016, 11:28:22 AM

Quote from: jeffandnicole on September 22, 2016, 11:00:32 AM

Quote from: DaBigE on September 22, 2016, 10:46:46 AM

Quote from: Brandon on September 22, 2016, 10:30:32 AM
Bullshit.  As soon as we're past the merge point around here, traffic speeds up.  The merge point IS the blockage point around Chicago.

Seconded. Anytime I've gone thru the Zoo Interchange construction zone zipper, traffic has sped up once we were out of the zipper.

So you guys go thru the merge zone 24 hours a day?  You guys have the vision of seeing conditions that exist at all times.

The only bullshit I see is that you're making numerous assumptions about traffic everywhere across the world.  What you need to do is sit above the construction zone to watch the entire thing develop.   "I went thru there on a Wednesday 3 weeks ago" doesn't qualify as knowing how these backups work.   All it takes is 86 year old Granny Thompson to drive 25 mph thru that construction zone 15 minutes ago to bottleneck everything up.

You don't have to go thru it 24 hours a day to figure it out. We know it. The regular drivers of the corridor know it. WisDOT knows it, otherwise they wouldn't have put up all of the dynamic warning signs regarding stopped/congested traffic, UPSTREAM of the merge. Ever watch material travel thru a funnel? An hourglass? It speeds up past the point of narrowing. Just as jemacedo09 says, it's when traffic is heavy that the merge point becomes the issue. What traffic is doing at 2:30 am isn't the focus, because it doesn't matter where you merge with traffic being so light.

I've watched material go thru a funnel.  What happens if you stop that funnel for a minute while adding material to the funnel?  The material builds up without any way of getting it thru. 

In construction zones, the construction equipment has to enter and exit.  Those trucks aren't going to pull in and out at 55 mph.  They slow down.  Depending on the construction zone, they may even have to stop and back in to the work area, causing a total traffic stoppage.  That's the stuff that you don't see going on out there because you're not one of those cars within eyesight of seeing it, but can mightly contribute to the delays.

Quote from: DaBigE on September 22, 2016, 10:46:46 AM

Quote from: Brandon on September 22, 2016, 10:30:32 AM
Bullshit.  As soon as we're past the merge point around here, traffic speeds up.  The merge point IS the blockage point around Chicago.

Seconded. Anytime I've gone thru the Zoo Interchange construction zone zipper, traffic has sped up once we were out of the zipper.

But if traffic merges too quickly into one lane, it's going to slow down. Cars cannot all universally react to a merge. Most react by braking to create a safe following distance, but that creates a chain reaction of braking, inevitably creating another slowdown. A safe gap to you, may not be a safe gap to the car behind you.

Rather than have multiple merge points, with multiple reactionary braking points, it's better just to have one. Use all the available lane space.

Regardless of whether early merge or late merge provides the highest theoretical throughput, there's another issue that I haven't seen mentioned. You could call it "equality of misery" .

It's somewhat like the prisoner's dilemma. You can look it up on Wikipedia if you're unfamiliar. The general concept was used in a show on Game Show Network some years ago called Friend or Foe. On that show, a team of two people would work together to win a jackpot, and then after they won, the two team members would secretly vote "friend"  or "foe" –under the table so that the teammate couldn't see how they voted. If both voted "friend" , they'd split the jackpot evenly. If both voted "foe" , neither one of them would take home anything. However if one voted "friend"  and the other voted "foe" , the trusting friend would leave empty-handed while the cynical foe would get the whole jackpot to himself.

A lane of a hundred early mergers–who all want to be good people and do the right thing–are essentially voting "friend" . They've all thrown their antes into the pot in the hopes of splitting it evenly. But this jackpot creates a very attractive opportunity for a handful of foes to scurry up the empty lane and snatch the spoils laying out in plain view. This leads to people coloring the situation in moral overtones: us, good people in the early merge lane...and them: bad people butting in line. This can easily escalate to vigilanteism among the "good"  folks and elevated acts of douchebaggery among the "bad" .

Even if late merge doesn't lead to higher throughput, it at least defuses the emotional powder keg. No prick in a BMW can steal the jackpot because there is no jackpot–everyone in both lanes has been waiting roughly an equal length of time.

Quote from: jakeroot on September 22, 2016, 11:56:29 AM

Quote from: DaBigE on September 22, 2016, 10:46:46 AM

Quote from: Brandon on September 22, 2016, 10:30:32 AM
Bullshit.  As soon as we're past the merge point around here, traffic speeds up.  The merge point IS the blockage point around Chicago.

Seconded. Anytime I've gone thru the Zoo Interchange construction zone zipper, traffic has sped up once we were out of the zipper.

But if traffic merges too quickly into one lane, it's going to slow down. Cars cannot all universally react to a merge. Most react by braking to create a safe following distance, but that creates a chain reaction of braking, inevitably creating another slowdown. A safe gap to you, may not be a safe gap to the car behind you.

Rather than have multiple merge points, with multiple reactionary braking points, it's better just to have one. Use all the available lane space.

That is basically the essence of it - before the obstacle speeds are higher and more real estate is available, leading to higher mobility of the cars. THat, among other things, means easy recovery of time lost in merge.
Once you're in the narrows, any delay means added delay for all the cars waiting.
So, what do you think would provide higher entrance rate into the narrows - pre-formed single lane, where all driver need is to maintain following distance to car in front - or last second lane change, where you have to keep an eye on at least 2 cars at the same time?
THat is small effect, maybe few %% of total throughput at most, though.

Quote from: jemacedo9 on September 22, 2016, 11:17:42 AM
I don't think there is any question around what to do when traffic is light:  merge over as soon as possible. But there is no adverse impact to when you merge, as long as you're not cutting someone off in the process at the last minute.  Besides the etiquette, that tends to slow down that person.

The arguments seems to be over what to do when traffic is heavy.  To that, here is the question:  is there any benefit to leave the closed lane empty by suggesting that the majority of people merge over early?  Om heavy traffic, a jam is going to exist whether everyone merges at the merge point, or if the majority of people merge early.

To me, the ideal situation is in heavy traffic everyone uses all lanes to the merge point, and then alternate. BUT...that only works if everyone alternates.  The second one person jumps their turn, this breaks down...but I don't see how the early merge solves this either.  Merging earlier might improve throughput at the merge point, but is negatively impacted at the earlier merge point.

Short answer:  is one really significantly better than the other?  Or are both no wins...when you factor in actual driver behavior? 

Exactly.  When traffic is light enough that there are still gaps, if everyone merges into a gap at a speed such that they don't force traffic behind them to slow down, it significantly reduces the chance of a backup.  The majority of backups I've ever been in have been caused by people messing this up, usually by cutting into a lane slower than traffic is moving in that lane without a sufficient gap to accelerate before the car behind then needs to slow down.

When traffic is heavy, of course, everyone should do a zipper merge at the same place.  Ideally that would be at the end of the lane rather than some random point, but I would rather everyone do a zipper merge all at the same point rather than most do it at one point and a few people heading down the rest of the lane, jumping the queue while forcing everyone else to stop to let them in instead of accelerate back up to speed.  The latter situation happens ALL THE TIME with my commute (in summer) with a couple acceleration lanes and it's EXTREMELY frustrating.

But changing lanes when there's no lane drop at point A versus changing lanes at point B a half-Mike farther back isn't necessarily better or worse. How does the presence of a lane drop make A better than B. Same action performed, same location, the only difference is the presence of road cones in a portion of the roadway not even being considered.

I guess to me there's a really simple solution to this:

1. If it is possible to change lanes before the merge point without coming to a complete stop or near complete stop and forcing your way in (causing vehicles in the adjacent lane to obviously need to brake) to do so, change lanes as soon as possible.

2. If it is impossible to change lanes before the merge point without coming to a complete stop or near complete stop and forcing your way in (causing vehicles in the adjacent lane to obviously need to brake) to do so, change lanes at the final merge point.

In practice, what this means is that you don't change lanes if it's going to require the car behind you to brake (in your own judgment), and as soon as you see a suitable gap, you should change lanes. If that is impossible, you will be forced to change lanes at the merge point, and there's nothing wrong with that.

I don't see why that is so complicated. There's no one-size-fits all solution. If traffic is flowing well, there's no point in impeding it by changing lanes at the final merge point. If traffic is moving slowly, just use the maximum amount of lane capacity and change lanes at the merge point. What's stupid is seeing somebody 200 feet before the merge stopped in a lane trying to wedge their way into the adjacent lane, holding everybody else up behind them. That person isn't driving correctly and is just adding a level of complexity to navigating traffic.  The actual merge point provides a visual cue to drivers in the continuing lane that they need to slow down to let cars in, whereas it's easy to blow by some poor sap sitting stopped in a non-ending lane with their turn signal on. That's where collisions happen. 

"The agreed upon merge location"? Says who? I see NO agreement on the roads, period. People get over at all sorts of different points and then they all seem to say, in essence, "Thou shall not use this lane past this point because I said so."

Quote from: 1995hoo on September 23, 2016, 07:38:53 AM
"The agreed upon merge location"? Says who? I see NO agreement on the roads, period. People get over at all sorts of different points and then they all seem to say, in essence, "Thou shall not use this lane past this point because I said so."

So you are that asshole, who drives in an empty lane past patiently waiting cars and demands an entry at the head of the queue?

Quote from: kalvado on September 23, 2016, 07:57:52 AM

Quote from: 1995hoo on September 23, 2016, 07:38:53 AM
"The agreed upon merge location"? Says who? I see NO agreement on the roads, period. People get over at all sorts of different points and then they all seem to say, in essence, "Thou shall not use this lane past this point because I said so."

So you are that asshole, who drives in an empty lane past patiently waiting cars and demands an entry at the head of the queue?

No, he's the smart one using the full capacity of the road like everyone else should be doing.

Quote from: Rothman on September 23, 2016, 09:13:27 AM

Quote from: kalvado on September 23, 2016, 07:57:52 AM

Quote from: 1995hoo on September 23, 2016, 07:38:53 AM
"The agreed upon merge location"? Says who? I see NO agreement on the roads, period. People get over at all sorts of different points and then they all seem to say, in essence, "Thou shall not use this lane past this point because I said so."

So you are that asshole, who drives in an empty lane past patiently waiting cars and demands an entry at the head of the queue?

No, he's the smart one using the full capacity of the road like everyone else should be doing.

I was also one of those kids who loved to use full capacity of the room by spreading things uniformly across entire floor...
But I don't understand what "full capacity" means in terms of highway usage. Is that the same as touching base on synergy to leverage joint efforts into meeting deliverable milestones?

Quote from: kalvado on September 23, 2016, 09:23:31 AM

Quote from: Rothman on September 23, 2016, 09:13:27 AM

Quote from: kalvado on September 23, 2016, 07:57:52 AM

Quote from: 1995hoo on September 23, 2016, 07:38:53 AM
"The agreed upon merge location"? Says who? I see NO agreement on the roads, period. People get over at all sorts of different points and then they all seem to say, in essence, "Thou shall not use this lane past this point because I said so."

So you are that asshole, who drives in an empty lane past patiently waiting cars and demands an entry at the head of the queue?

No, he's the smart one using the full capacity of the road like everyone else should be doing.

I was also one of those kids who loved to use full capacity of the room by spreading things uniformly across entire floor...
But I don't understand what "full capacity" means in terms of highway usage. Is that the same as touching base on synergy to leverage joint efforts into meeting deliverable milestones?

No.

PennDOT has signs in some work zones where they want to have a zipper merge...one stating "USE BOTH LANES TO MERGE POINT" and then at the merge point, "MERGE HERE - TAKE YOUR TURN".  THIS would clear things up quite nicely if used more widespread where engineers determined a zipper merge should be used.

Quote from: Rothman on September 23, 2016, 09:29:25 AM

Quote from: kalvado on September 23, 2016, 09:23:31 AM

Quote from: Rothman on September 23, 2016, 09:13:27 AM

Quote from: kalvado on September 23, 2016, 07:57:52 AM

Quote from: 1995hoo on September 23, 2016, 07:38:53 AM
"The agreed upon merge location"? Says who? I see NO agreement on the roads, period. People get over at all sorts of different points and then they all seem to say, in essence, "Thou shall not use this lane past this point because I said so."

So you are that asshole, who drives in an empty lane past patiently waiting cars and demands an entry at the head of the queue?

No, he's the smart one using the full capacity of the road like everyone else should be doing.

I was also one of those kids who loved to use full capacity of the room by spreading things uniformly across entire floor...
But I don't understand what "full capacity" means in terms of highway usage. Is that the same as touching base on synergy to leverage joint efforts into meeting deliverable milestones?

No.

But it is equally meaningless.
I mean "full capacity" in this situation does not translate into anything meaningful.
Travel times are not reduced
Safety is not improved.
Maintenance costs do rot reduce.
Nothing.

This is just another piece of managementspeak.

Feel free to explain why I am wrong, but try to be technical, no bullshit please.

Quote from: paulthemapguy on September 23, 2016, 09:30:38 AM
If the volume exceeds the capacity for a single lane, jamming and delays will occur in the continuing lane as people try to change out of the terminating lane--in this case, early merging would only worsen the jam (case 2 as described above).

Wrong.

Quote from: kalvado on September 23, 2016, 10:05:28 AM

Quote from: paulthemapguy on September 23, 2016, 09:30:38 AM
If the volume exceeds the capacity for a single lane, jamming and delays will occur in the continuing lane as people try to change out of the terminating lane--in this case, early merging would only worsen the jam (case 2 as described above).

Wrong.

Excellent refutation 10/10  :clap:  :wow:  :love:  :camera: :clap: :spin: :wow: ;-) :awesomeface:

Quote from: paulthemapguy on September 23, 2016, 12:59:24 PM

Quote from: kalvado on September 23, 2016, 10:05:28 AM

Quote from: paulthemapguy on September 23, 2016, 09:30:38 AM
If the volume exceeds the capacity for a single lane, jamming and delays will occur in the continuing lane as people try to change out of the terminating lane--in this case, early merging would only worsen the jam (case 2 as described above).

Wrong.

Excellent refutation 10/10  :clap:  :wow:  :love:  :camera: :clap: :spin: :wow: ;-) :awesomeface:

Yup. Between that and calling people "assholes" and the like, I wonder if he's someone else in disguise. No matter. I don't see much point wasting time answering that sort of nonsense, so I think I'm done with this thread. He can do whatever he wants.

Quote from: paulthemapguy on September 23, 2016, 12:59:24 PM

Quote from: kalvado on September 23, 2016, 10:05:28 AM

Quote from: paulthemapguy on September 23, 2016, 09:30:38 AM
If the volume exceeds the capacity for a single lane, jamming and delays will occur in the continuing lane as people try to change out of the terminating lane--in this case, early merging would only worsen the jam (case 2 as described above).

Wrong.

Excellent refutation 10/10  :clap:  :wow:  :love:  :camera: :clap: :spin: :wow: ;-) :awesomeface:

I wrote full explanation at least twice before. Try looking things up on a previous page. 

Quote from: kphoger on September 23, 2016, 01:32:59 PM
Again, speed differential while merging is the culprit.  Once everyone has actually merged, braked, adjusted following distance, etc., then things can get back to somewhat-normal.  I remain unconvinced that exactly where than merging happens is all that important, which is why some states are jumping on the zipper merge (Kansas) and some states have big orange signs saying <-- STATE LAW MERGE NOW (Oklahoma) a mile in advance.  There's no obvious benefit to either one.

Exactly.  If there's space to merge into a gap without affecting traffic, do so.  If not, have everyone do a zipper merge.  The end of the lane would be the most logical place, but if everyone's doing it elsewhere, don't be the guy butting in down the road.

Quote from: kalvado on September 23, 2016, 01:38:23 PM

Quote from: paulthemapguy on September 23, 2016, 12:59:24 PM

Quote from: kalvado on September 23, 2016, 10:05:28 AM

Quote from: paulthemapguy on September 23, 2016, 09:30:38 AM
If the volume exceeds the capacity for a single lane, jamming and delays will occur in the continuing lane as people try to change out of the terminating lane--in this case, early merging would only worsen the jam (case 2 as described above).

Wrong.

Excellent refutation 10/10  :clap:  :wow:  :love:  :camera: :clap: :spin: :wow: ;-) :awesomeface:

I wrote full explanation at least twice before. Try looking things up on a previous page.

And ya still didn't learn anything.  From me, from jake, from any of the people who have made pretty much the same point as I did.  So we'll just agree to disagree I guess.

And vdeane summed up the general conclusion pretty well in the post above.

Quote from: paulthemapguy on September 23, 2016, 02:42:03 PM

Quote from: kalvado on September 23, 2016, 01:38:23 PM

Quote from: paulthemapguy on September 23, 2016, 12:59:24 PM

Quote from: kalvado on September 23, 2016, 10:05:28 AM

Quote from: paulthemapguy on September 23, 2016, 09:30:38 AM
If the volume exceeds the capacity for a single lane, jamming and delays will occur in the continuing lane as people try to change out of the terminating lane--in this case, early merging would only worsen the jam (case 2 as described above).

Wrong.

Excellent refutation 10/10  :clap:  :wow:  :love:  :camera: :clap: :spin: :wow: ;-) :awesomeface:

I wrote full explanation at least twice before. Try looking things up on a previous page.

And ya still didn't learn anything.  From me, from jake, from any of the people who have made pretty much the same point as I did.  So we'll just agree to disagree I guess.

And vdeane summed up the general conclusion pretty well in the post above.

Well, point is that zipper merge elsewhere, as vdeane called it, is effectively an early merge. As long as you agree that is an equally good (or bad - since there is no truly good option here) alternative, we're on the same page.

Quote from: kalvado on September 23, 2016, 03:11:31 PM

Quote from: paulthemapguy on September 23, 2016, 02:42:03 PM

Quote from: kalvado on September 23, 2016, 01:38:23 PM

Quote from: paulthemapguy on September 23, 2016, 12:59:24 PM

Quote from: kalvado on September 23, 2016, 10:05:28 AM

Quote from: paulthemapguy on September 23, 2016, 09:30:38 AM
If the volume exceeds the capacity for a single lane, jamming and delays will occur in the continuing lane as people try to change out of the terminating lane--in this case, early merging would only worsen the jam (case 2 as described above).

Wrong.

Excellent refutation 10/10  :clap:  :wow:  :love:  :camera: :clap: :spin: :wow: ;-) :awesomeface:

I wrote full explanation at least twice before. Try looking things up on a previous page.

And ya still didn't learn anything.  From me, from jake, from any of the people who have made pretty much the same point as I did.  So we'll just agree to disagree I guess.

And vdeane summed up the general conclusion pretty well in the post above.

Well, point is that zipper merge elsewhere, as vdeane called it, is effectively an early merge. As long as you agree that is an equally good (or bad - since there is no truly good option here) alternative, we're on the same page.

I'm not convinced that a single merge point–whether early or late–is actually any better than scattered merge points along the path.  The only thing that seems to be universally agreed upon is that coming to a dead stop at the cones and then merging at 4 mph is bad.  Everything else so far has been argued to death but not really supported by actual data.

Okay, I see the point about a single merge point even if it is early though.  Ideally, if everyone merges at the same point, the effect will be exactly the same as if everyone waited until the last second.  But good luck trying to make everyone agree on the same arbitrary point, when you can just do the normal expected thing and wait until the point that's geographically defined!  It's an impossible proposition, getting everyone to think exactly like you.  And furthermore, shifting the merge to a single earlier point will cause a backward shift of the front and back endpoints of the resulting queue.  The jam will end earlier and also start earlier, causing a greater probability of blocking intersections and driveways upstream of the merge.

Quote from: kphoger on September 23, 2016, 03:15:39 PM

Quote from: kalvado on September 23, 2016, 03:11:31 PM

Quote from: paulthemapguy on September 23, 2016, 02:42:03 PM

Quote from: kalvado on September 23, 2016, 01:38:23 PM

Quote from: paulthemapguy on September 23, 2016, 12:59:24 PM

Quote from: kalvado on September 23, 2016, 10:05:28 AM

Quote from: paulthemapguy on September 23, 2016, 09:30:38 AM
If the volume exceeds the capacity for a single lane, jamming and delays will occur in the continuing lane as people try to change out of the terminating lane--in this case, early merging would only worsen the jam (case 2 as described above).

Wrong.

Excellent refutation 10/10  :clap:  :wow:  :love:  :camera: :clap: :spin: :wow: ;-) :awesomeface:

I wrote full explanation at least twice before. Try looking things up on a previous page.

And ya still didn't learn anything.  From me, from jake, from any of the people who have made pretty much the same point as I did.  So we'll just agree to disagree I guess.

And vdeane summed up the general conclusion pretty well in the post above.

Well, point is that zipper merge elsewhere, as vdeane called it, is effectively an early merge. As long as you agree that is an equally good (or bad - since there is no truly good option here) alternative, we're on the same page.

I'm not convinced that a single merge point–whether early or late–is actually any better than scattered merge points along the path.  The only thing that seems to be universally agreed upon is that coming to a dead stop at the cones and then merging at 4 mph is bad.  Everything else so far has been argued to death but not really supported by actual data.

Let people settle with idea that merging at last instant (with coming to complete stop and forcing way into a formed line)  is not the best option. Then we may talk about distributed, early, late and what not.
And actually there are 2 groups here.

Quote from: Rothman on September 23, 2016, 09:13:27 AM

Quote from: kalvado on September 23, 2016, 07:57:52 AM

Quote from: 1995hoo on September 23, 2016, 07:38:53 AM
"The agreed upon merge location"? Says who? I see NO agreement on the roads, period. People get over at all sorts of different points and then they all seem to say, in essence, "Thou shall not use this lane past this point because I said so."

So you are that asshole, who drives in an empty lane past patiently waiting cars and demands an entry at the head of the queue?

No, he's the smart one using the full capacity of the road like everyone else should be doing.

Quote from: paulthemapguy on September 23, 2016, 03:51:52 PM
Okay, I see the point about a single merge point even if it is early though.  Ideally, if everyone merges at the same point, the effect will be exactly the same as if everyone waited until the last second.  But good luck trying to make everyone agree on the same arbitrary point, when you can just do the normal expected thing and wait until the point that's geographically defined!  It's an impossible proposition, getting everyone to think exactly like you.  And furthermore, shifting the merge to a single earlier point will cause a backward shift of the front and back endpoints of the resulting queue.  The jam will end earlier and also start earlier, causing a greater probability of blocking intersections and driveways upstream of the merge.

Single point early merge, from my experience,  is usually "once you see a line waiting - join the end of the line". Not conceptually different from zipper, first in-first out.
Usually once the reason for the merge (accident, stopped vehicle, "lane end" sign) is no longer in sight from points at the end of the queue, people no longer know where to merge, and single point merge (usually several car lengths - consistent with openings in continuing lane)  moves to the point where sign/accident is visible. Traffic is moving in congestion mode at that point anyway.

What I see as a wrong behavior is driving  in already vacated lane past a formed line and jumping the queue at the cones. But some see that as "using all available resources".

Quote from: jemacedo9 on September 23, 2016, 09:55:46 AM
PennDOT has signs in some work zones where they want to have a zipper merge...one stating "USE BOTH LANES TO MERGE POINT" and then at the merge point, "MERGE HERE - TAKE YOUR TURN".  THIS would clear things up quite nicely if used more widespread where engineers determined a zipper merge should be used.

Yes.  In addition to the signs, they tried to get the word out in print and TV media (when doing press releases about the construction projects) on how to properly merge as well.  I gotta give PennDOT some credit there.

Quote from: kphoger on September 23, 2016, 03:15:39 PM
I'm not convinced that a single merge point–whether early or late–is actually any better than scattered merge points along the path.

Having been in zones with no indication on "how" / where to merge, and thru the explicit "Zipper Merge" that PennDOT has been pushing - and almost everyone actually doing so - I can say that I am convinced that it is better.  (And I have at least 2 friends who now think so, and at least 1 thought it was stupid when they started popping up a few years ago)

Quote from: kalvado on September 23, 2016, 04:01:33 PM

Quote from: kphoger on September 23, 2016, 03:15:39 PM
The only thing that seems to be universally agreed upon is that coming to a dead stop at the cones and then merging at 4 mph is bad. 

Let people settle with idea that merging at last instant (with coming to complete stop and forcing way into a formed line) is not the best option.

Merging at the last instant with coming to complete stop and forcing way into a formed line is not the same thing as merging at the last instant without doing so.  You seem to be missing the fact that a zipper merge explicitly expects people in both lanes to take turns at the merge point.  There's no such thing as "forcing your way in" at a true zipper merge, because there is no "right" and "wrong" lane to be in.  It's essentially a "form one lane" situation.  This notion of zooming past traffic or coming to a stop in the "ending lane" is by nature contrary to what a zipper merge is intended to do, which is to make both lanes the "ending lane" or, if you prefer, both lanes the "continuing lane."

Quote from: kphoger on September 23, 2016, 04:44:56 PM

Quote from: kalvado on September 23, 2016, 04:01:33 PM

Quote from: kphoger on September 23, 2016, 03:15:39 PM
The only thing that seems to be universally agreed upon is that coming to a dead stop at the cones and then merging at 4 mph is bad. 

Let people settle with idea that merging at last instant (with coming to complete stop and forcing way into a formed line) is not the best option.

Merging at the last instant with coming to complete stop and forcing way into a formed line is not the same thing as merging at the last instant without doing so.  You seem to be missing the fact that a zipper merge explicitly expects people in both lanes to take turns at the merge point.  There's no such thing as "forcing your way in" at a true zipper merge, because there is no "right" and "wrong" lane to be in.  It's essentially a "form one lane" situation.  This notion of zooming past traffic or coming to a stop in the "ending lane" is by nature contrary to what a zipper merge is intended to do, which is to make both lanes the "ending lane" or, if you prefer, both lanes the "continuing lane."

you're 100% right, we're not only on the same page, we're on the same line.
Earlier in this thread there was a great idea - which I totally like: do not go against common trend. Everyone merges at last point - let that go smoothly and merge there. Everyone merges early - let that go smoothly.  Outcome is the same, give or take a tiny bit.

Look again at Rothman's and 1995hoo's comments: their point is if everyone is doing it wrong, I will still do it right by merging at the end. And that is the problem from my perspective.

Quote from: kalvado on September 23, 2016, 05:08:36 PM

Look again at Rothman's and 1995hoo's comments: their point is if everyone is doing it wrong, I will still do it right by merging at the end. And that is the problem from my perspective.

Glad to know that we're doing it right and you're doing it wrong, then.

My main problem with early merging is that it the expectation can lead to road rage.  A driver zooming past everyone in the near-vacant lane and then butting in makes the other drivers angry and encourages them to tail-gate in order to box him out; then, when he does find a spot, people have to brake.  Also, if early merging is the expectation, then there are the vigilantes who think it's their job to ride the center stripe and block people from using the near-vacant lane, which encourages potentially unsafe maneuvers on the shoulder.

Quote from: Rothman on September 23, 2016, 05:33:23 PM

Quote from: kalvado on September 23, 2016, 05:08:36 PM

Look again at Rothman's and 1995hoo's comments: their point is if everyone is doing it wrong, I will still do it right by merging at the end. And that is the problem from my perspective.

Glad to know that we're doing it right and you're doing it wrong, then.

Well, First Amendment says you are always entitled for your wrong opinion

Quote from: kalvado on September 23, 2016, 05:08:36 PM

Quote from: kphoger on September 23, 2016, 04:44:56 PM

Quote from: kalvado on September 23, 2016, 04:01:33 PM

Quote from: kphoger on September 23, 2016, 03:15:39 PM
The only thing that seems to be universally agreed upon is that coming to a dead stop at the cones and then merging at 4 mph is bad. 

Let people settle with idea that merging at last instant (with coming to complete stop and forcing way into a formed line) is not the best option.

Merging at the last instant with coming to complete stop and forcing way into a formed line is not the same thing as merging at the last instant without doing so.  You seem to be missing the fact that a zipper merge explicitly expects people in both lanes to take turns at the merge point.  There's no such thing as "forcing your way in" at a true zipper merge, because there is no "right" and "wrong" lane to be in.  It's essentially a "form one lane" situation.  This notion of zooming past traffic or coming to a stop in the "ending lane" is by nature contrary to what a zipper merge is intended to do, which is to make both lanes the "ending lane" or, if you prefer, both lanes the "continuing lane."

you're 100% right, we're not only on the same page, we're on the same line.
Earlier in this thread there was a great idea - which I totally like: do not go against common trend. Everyone merges at last point - let that go smoothly and merge there. Everyone merges early - let that go smoothly.  Outcome is the same, give or take a tiny bit.

Look again at Rothman's and 1995hoo's comments: their point is if everyone is doing it wrong, I will still do it right by merging at the end. And that is the problem from my perspective.

There is room in this world for a campaign to change the common trend.  In my opinion, the zipper merge wastes less pavement for vehicle storage in the event of jams, encourages fair respect by/for drivers in both lanes, gives a clear expectation of behavior, and offers no significant disadvantage over early merging.  So I'm in favor of campaigns to implement the zipper merge, even if it doesn't actually improve the delay impact of jams to any degree whatsoever.

Quote from: kphoger on September 23, 2016, 06:07:20 PM
There is room in this world for a campaign to change the common trend.  In my opinion, the zipper merge wastes less pavement for vehicle storage in the event of jams, encourages fair respect by/for drivers in both lanes, gives a clear expectation of behavior, and offers no significant disadvantage over early merging.  So I'm in favor of campaigns to implement the zipper merge, even if it doesn't actually improve the delay impact of jams to any degree whatsoever.

There is room in this world for a lot of different things - but we cannot afford all of them at the same time.
Question is if such campaign would be cost effective; and where it has to start.
One of interesting questions is legal meaning of this sign:
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fwww.safetysupplywarehouse.com%2Fv%2Fvspfiles%2Fphotos%2FW14351-2.jpg&hash=f3a8f1712b5c9f961d71145ad2b846d371d5e82a)
I believe (maybe I couldn't find appropriate paragraph) NY doesn't define driver behavior. To the point of authorities interpreting things differently.
I believe I have seen "ending lane yields" and "both lanes equal" in other state's laws.
Which basically means zipper campaign has to start with states legislation harmonization - and that is EXPENSIVE.

Quote from: kalvado on September 23, 2016, 06:25:40 PM

Quote from: kphoger on September 23, 2016, 06:07:20 PM
There is room in this world for a campaign to change the common trend.  In my opinion, the zipper merge wastes less pavement for vehicle storage in the event of jams, encourages fair respect by/for drivers in both lanes, gives a clear expectation of behavior, and offers no significant disadvantage over early merging.  So I'm in favor of campaigns to implement the zipper merge, even if it doesn't actually improve the delay impact of jams to any degree whatsoever.

There is room in this world for a lot of different things - but we cannot afford all of them at the same time.
Question is if such campaign would be cost effective; and where it has to start.
One of interesting questions is legal meaning of this sign:
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fwww.safetysupplywarehouse.com%2Fv%2Fvspfiles%2Fphotos%2FW14351-2.jpg&hash=f3a8f1712b5c9f961d71145ad2b846d371d5e82a)
I believe (maybe I couldn't find appropriate paragraph) NY doesn't define driver behavior. To the point of authorities interpreting things differently.
I believe I have seen "ending lane yields" and "both lanes equal" in other state's laws.
Which basically means zipper campaign has to start with states legislation harmonization - and that is EXPENSIVE.

I have never seen this signage at a zipper merge.

Quote from: kphoger on September 23, 2016, 06:29:45 PM

Quote from: kalvado on September 23, 2016, 06:25:40 PM

Quote from: kphoger on September 23, 2016, 06:07:20 PM
There is room in this world for a campaign to change the common trend.  In my opinion, the zipper merge wastes less pavement for vehicle storage in the event of jams, encourages fair respect by/for drivers in both lanes, gives a clear expectation of behavior, and offers no significant disadvantage over early merging.  So I'm in favor of campaigns to implement the zipper merge, even if it doesn't actually improve the delay impact of jams to any degree whatsoever.

There is room in this world for a lot of different things - but we cannot afford all of them at the same time.
Question is if such campaign would be cost effective; and where it has to start.
One of interesting questions is legal meaning of this sign:
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fwww.safetysupplywarehouse.com%2Fv%2Fvspfiles%2Fphotos%2FW14351-2.jpg&hash=f3a8f1712b5c9f961d71145ad2b846d371d5e82a)
I believe (maybe I couldn't find appropriate paragraph) NY doesn't define driver behavior. To the point of authorities interpreting things differently.
I believe I have seen "ending lane yields" and "both lanes equal" in other state's laws.
Which basically means zipper campaign has to start with states legislation harmonization - and that is EXPENSIVE.

I have never seen this signage at a zipper merge.

Yet it is default sign for lane end - and a point where lanes have to merge. Defining default right of way at merge - each and every merge - is a must if you want to achieve uniform motorist compliance. Interestingly enough, that may include merge of highway acceleration lanes. 

Quote from: kalvado on September 23, 2016, 06:33:03 PM
Defining default right of way at merge - each and every merge - is a must if you want to achieve uniform motorist compliance.

I do not agree with that statement.  "Take turns" or "Form one lane" is an appropriate indication.

Quote from: kphoger on September 23, 2016, 06:41:32 PM

Quote from: kalvado on September 23, 2016, 06:33:03 PM
Defining default right of way at merge - each and every merge - is a must if you want to achieve uniform motorist compliance.

I do not agree with that statement.  "Take turns" or "Form one lane" is an appropriate indication.

Well, then you need to make sure drivers post appropriate sign before they crash and close that damn lane..  :sombrero:
Or you still need a law (52 of thm, including DC and PR) defining default behavior and mechanisms to override the default....

Quote from: kalvado on September 23, 2016, 06:49:58 PM

Quote from: kphoger on September 23, 2016, 06:41:32 PM

Quote from: kalvado on September 23, 2016, 06:33:03 PM
Defining default right of way at merge - each and every merge - is a must if you want to achieve uniform motorist compliance.

I do not agree with that statement.  "Take turns" or "Form one lane" is an appropriate indication.

Well, then you need to make sure drivers post appropriate sign before they crash and close that damn lane..
Or you still need a law (52 of thm, including DC and PR) defining default behavior and mechanisms to override the default....

Why can't the default law be, "take turns when forming single-file line"? If a crash occurs at the merge point, the fault is 50/50. Having one lane with absolute priority promotes road rage, because those drivers rightfully have the right of way, and can single-handedly ruin a zipper merge. Many drivers merge in advance because they know the drivers in the thru-lane don't have to let them in. If the law designated both lanes as equal, and any collision at the merge point as having 50/50 fault, drivers might be more likely to treat a merge with capitulation.

Then again, I'm not a law-specialist; maybe this type of law isn't allowed to exist.

Quote from: jakeroot on September 23, 2016, 08:06:15 PM

Quote from: kalvado on September 23, 2016, 06:49:58 PM

Quote from: kphoger on September 23, 2016, 06:41:32 PM

Quote from: kalvado on September 23, 2016, 06:33:03 PM
Defining default right of way at merge - each and every merge - is a must if you want to achieve uniform motorist compliance.

I do not agree with that statement.  "Take turns" or "Form one lane" is an appropriate indication.

Well, then you need to make sure drivers post appropriate sign before they crash and close that damn lane..
Or you still need a law (52 of thm, including DC and PR) defining default behavior and mechanisms to override the default....

Why can't the default law be, "take turns when forming single-file line"? If a crash occurs at the merge point, the fault is 50/50. Having one lane with absolute priority promotes road rage, because those drivers rightfully have the right of way, and can single-handedly ruin a zipper merge. Many drivers merge in advance because they know the drivers in the thru-lane don't have to let them in. If the law designated both lanes as equal, and any collision at the merge point as having 50/50 fault, drivers might be more likely to treat a merge with capitulation.

Then again, I'm not a law-specialist; maybe this type of law isn't allowed to exist.

Next thing you have to explain how such merge is different from highway acceleration lane merge. Or - as we have here - a merge with an extra lane going through traffic light. merge after passing.
I am sure if I make a post on "weird lane ends" there will be a bunch of examples from all over the place. Problem is that the law must address ALL of them in some sensible way.
A lot of these things actually hang on common courtesy - like truck drivers moving over to let traffic from the ramp into the flow.  If you will, that is sort of why i emphasize "common" way of doing things...

Quote from: kalvado on September 23, 2016, 08:37:24 PM
A lot of these things actually hang on common courtesy - like truck drivers moving over to let traffic from the ramp into the flow.  If you will, that is sort of why i emphasize "common" way of doing things...

On this last point. Washington's "Keep right except to pass" law (RCW 46.61.100) has a section on moving left to allow people to merge:

Quote from: RCW 46.61.100
Upon all roadways having two or more lanes for traffic moving in the same direction, all vehicles shall be driven in the right-hand lane then available for traffic, except...(c) when moving left to allow traffic to merge...

As far as I'm aware, on a regular lane drop, the lane that is ending must yield to the lane that is continuing and that somebody in that lane should merge when it is prudent to do so and not wait to the last minute.

There are places, though, where a zipper merge is preferred.  For example, where construction normally closes a lane, this is the preferred method.  And generally there will be some signs to state that, although the signs aren't very clear.

I know of a permanent zipper merge in the Baltimore area on I-70 approaching the north I-695 ramp.  They have some very good signage there.

FORM SINGLE LANE AHEAD:
https://www.google.com/maps/@39.3053042,-76.7492325,3a,75y,113.46h,81.94t/data=!3m6!1e1!3m4!1sUKj_IxMECx2XNI5Ih0EuGw!2e0!7i13312!8i6656

ALTERNATE RIGHT OF WAY, with yellow diamond sign showing both lanes merging to the middle.  It's a little different than the sign posted earlier in the thread:
https://www.google.com/maps/@39.3047953,-76.7475411,3a,75y,113.46h,81.94t/data=!3m6!1e1!3m4!1sllG0iY8qvW7-6aG1xit-TQ!2e0!7i13312!8i6656

FORM SINGLE LANE NOW:
https://www.google.com/maps/@39.3048744,-76.7460204,3a,75y,52.67h,78.61t/data=!3m6!1e1!3m4!1s3futPYb7D5RVhCC_M7cvCw!2e0!7i13312!8i6656

So here, there is a purposeful zipper merge.  The three lanes of I-70 essentially come to an end at I-695.  Originally, the right lane led to I-695 south, the middle lane to I-695 north, and the left lane led to the park and ride.  Now, the right lane leads to I-695 south and the left two lanes lead to I-695 north, with a left exit to the park and ride.  [Very little traffic heads that way.]  Even though two lanes of traffic go to I-70, the ramp narrows at a point to one lane and there used to be tremendous backups here.  By encouraging the zipper merge, the backup is allowed to spread over both lanes, so it is not as severe.

In Idaho, the drivers manual states that "merging traffic must yield" on a normal lane drop (eg the following sign).
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fwww.safetysupplywarehouse.com%2Fv%2Fvspfiles%2Fphotos%2FW14351-2.jpg&hash=f3a8f1712b5c9f961d71145ad2b846d371d5e82a)

The Ada County Highway Distric Road Wizard has talked about merging a fair amount in the newspaper column (which by the way is quite interesting to read for road geeks).

Here's one example, this one on a surface street, but same idea as a freeway.

Quote
Dear Road Wizard: With abundant two-thru-lane intersections that merge down to one lane past the intersection in Boise, and especially Meridian, why don't Idaho drivers happily alternately merge (like most other states) for faster movement of traffic? Here drivers line up for blocks in the left-most thru lane instead of also using the right-most thru lane and merging down to one for fear of road rage and people saying they "cut them off." The intersection of Eagle Road and Chinden Boulevard is a prime example. Don't people realize that everyone will move faster if they allow merging? Merging is not "cutting someone off,” it's a rule of the road. Paula


The classic thru-traffic showdown. In one corner of the ring, a driver in the left-most thru lane who has waited out multiple signal cycles during rush hour traffic to finally make the green light. In the other, a motorist who has used the right-most thru lane to zip past drivers on the left, demanding to merge where the right lane ends past the signal. Who deserves the title of “First Down the Road”?

Preventing someone from merging may feel like winning the battle, but it’s really losing the war, which is otherwise known as the struggle to get everyone into the one lane in the most efficient way. The better approach is for drivers in the left-most lane to leave gaps for merging traffic while maintaining a steady speed. People in the right-most lane should look for those gaps and try to merge at about the same speed as traffic to the left. Motorists should use—but not abuse—either lane. Don’t be shy (or rude)!

Source: http://www.achdidaho.org/Departments/PR/RoadWizard/Entries.aspx?MID=451

And 2 weeks later:

Quote
Dear Road Wizard: I'm glad “Paula” brought up the two thru lanes on Chinden Boulevard at Eagle Road. You see, I'm one of those guys who wait in line on the left for traffic to proceed past the light. Why do I do this? It’s because I'm following the rules of the road. There is only one westbound thru lane on Chinden past Eagle Road. The right-hand lane past the signal is designated as a turn lane into the Banbury subdivision. Problem is, folks like Paula think it’s a merge lane and use it to cut off drivers in the correct thru lane. By the time four or five cycles pass and a person in the left lane finally makes it to the light, most have no compassion for the "cheater" who is in the right lane. Does anyone share my view? Dan


I decided to be one of “those” people who use the right-most thru lane to pass drivers on the left at this intersection, then cut into traffic at the last minute where the right lane ends just beyond the signal.

Drivers in the left-most thru lane made room for those of us merging from the right, and everyone got down the road smoothly without any noticeable anger or inappropriate gesturing.

People don’t always behave this way, but the right lane actually is a designated merge lane. There is a sign posted and painted arrows (somewhat faded) on the lane that direct drivers to merge. The lane then becomes a right-turn-only entrance to the Banbury subdivision. A source of confusion, perhaps, and maybe “cheaters” are going too far past the merge point, but Paula had it right. Both thru lanes at the intersection can be used by drivers continuing westward.

Source: http://www.achdidaho.org/Departments/PR/RoadWizard/Entries.aspx?MID=452

I go through the I-184/I-84 westbound interchange during rush hour, where it's basically 6 lanes of traffic (from left to right: 3 lanes I-84, 2 lanes I-184, 1 lane Franklin Rd.) merge into 4 lanes, where the far two right lanes end. The traffic in the farther left lanes (I-84) is much lighter than the traffic coming from I-184, which all has to merge. The farthest left I-184 lane (the one that does not end) backs up way farther than the other I-184 lane. I always take the right-most of those lanes. I cruise in that lane until a large gap to my left appears (usually happens after the ramp from Franklin merges in, and where it's 5 lanes, but before the farthest right lane ends). Only a small handful of times I've had to ride it out all the way to the end of that lane. When I did, I had no trouble merging in, nobody "blocked me out". But people here do tend to merge really early, often clogging up the non-merging lane.

I feel like that interchange might be better if one lane on the left ended (instead of a second right lane ending), but that could slow things down outside of commuting hours (where I-184 traffic is light), and increase weaving of I-84 drivers getting into the far right lane to exit at Eagle Rd./ID-55. So I don't know if it would be that much better.

In many cases, the road markings are designed for the busiest times, so it appears that it would be most helpful if lanes on both the left and the right merged and not put the full onus of merging on I-184 traffic.

So generally speaking, if 6 lanes merge rapidly to 4 lanes, it seems it would make the most sense to have the left most lane and the right most lane end, instead of quickly ending two lanes on one side or the other.  But the highway authorities apparently disagree.

Quote from: mrsman on September 30, 2016, 05:29:36 PM
In many cases, the road markings are designed for the busiest times, so it appears that it would be most helpful if lanes on both the left and the right merged and not put the full onus of merging on I-184 traffic.

So generally speaking, if 6 lanes merge rapidly to 4 lanes, it seems it would make the most sense to have the left most lane and the right most lane end, instead of quickly ending two lanes on one side or the other.  But the highway authorities apparently disagree.

Traffic merging from both sides is generally a disaster.

I said I wasn't going to waste my time with this thread any more given the troll.

But then this afternoon I thought of a semi-related question. It's not quite the same issue, but I think it's pretty close. See Google Maps satellite view linked below of I-66 near Fair Oaks Mall in Fairfax. I was getting onto the highway via the ramp that curves in from the top right of the picture (I had been at an all-day meeting near Fair Oaks and for some stupid reason I decided to take I-66 west to the Fairfax County Parkway, not thinking about what the rain would do to the traffic). Traffic on I-66 was at pretty much a complete standstill, or at best what the radio in Raleigh used to call "stop-and-roll" where you use the clutch more than the accelerator.

I think most of us would agree that it is not appropriate for someone who has nobody ahead of him in the onramp merge lane (I won't say "acceleration lane" given how slow traffic was) to come to a stop right at the point where the shoulder changes color, well before even the end of the solid single white line. Yet that is what some guy in a minivan did, putting his blinker on and sitting there. Why in the world would you not continue down the merge lane in this situation?

https://www.google.com/maps/@38.8612864,-77.3531256,179m/data=!3m1!1e3

For those early mergers, I'm curious what you all think of the frequent expansion of roads at "choke points" only to return to the smaller size right after them. Should we not use the expansions designed to alleviate traffic?

For example, when too many people are trying to turn left onto a road or highway, they frequently install a second left turn lane and a few hundred feet of a second lane on the road to the left to allow people to merge without requiring the left turn signal to be green and impeding the opposing thru traffic for so long?

Also, I know in Palm Beach County, they frequently install a 2nd or 3rd lane for a few hundred feet before a busy intersection only for it to end a few hundred feet after, so people can "skip the line" and not get stuck missing a light cycle. Doing this seems to successfully allow the road to handle much more traffic without the expense of expanding the entire road to 3 lanes, such as if you look at eastbound Clint Moore here: https://www.google.com/maps/@26.4077098,-80.1464466,195m/data=!3m1!1e3

They usually seem to try to expand all the intersections first to alleviate traffic, and only after that begins to fail, connect the 3rd lanes at the intersections (which also makes that eventual 3rd lane construction much less disruptive, as they don't need to rebuild the intersections at that point). If we're all supposed to early merge, wouldn't we never use these lanes specifically designed for us to enter so we can pass the choke point?

Quote from: UCFKnights on October 02, 2016, 08:32:12 PM
For those early mergers, I'm curious what you all think of the frequent expansion of roads at "choke points" only to return to the smaller size right after them. Should we not use the expansions designed to alleviate traffic?

For example, when too many people are trying to turn left onto a road or highway, they frequently install a second left turn lane and a few hundred feet of a second lane on the road to the left to allow people to merge without requiring the left turn signal to be green and impeding the opposing thru traffic for so long?

Also, I know in Palm Beach County, they frequently install a 2nd or 3rd lane for a few hundred feet before a busy intersection only for it to end a few hundred feet after, so people can "skip the line" and not get stuck missing a light cycle. Doing this seems to successfully allow the road to handle much more traffic without the expense of expanding the entire road to 3 lanes, such as if you look at eastbound Clint Moore here: https://www.google.com/maps/@26.4077098,-80.1464466,195m/data=!3m1!1e3

They usually seem to try to expand all the intersections first to alleviate traffic, and only after that begins to fail, connect the 3rd lanes at the intersections (which also makes that eventual 3rd lane construction much less disruptive, as they don't need to rebuild the intersections at that point). If we're all supposed to early merge, wouldn't we never use these lanes specifically designed for us to enter so we can pass the choke point?

I know what you're talking about - and my feeling is that idea may work, but actual design is usually awful over here.  Of 5 or 6 spots I can think of, only one somewhat works. Well, local road designers are only in third decade of learning curve on the matter...
Overall, for the concept to work as designed, you need vehicles in the "main" lane to pass coke point - intersection or turn - at a rate of 1 car every 4-5 seconds. Looks like even most underpowered US vehicles (and from my observations, Jeep Patriot tends to be the worst among passenger cars) can do less than 3 seconds on level road. Maybe different in more fuel economy - conscious places. So from my experience those lanes can in fact be used only to pass a known slow vehicle - e.g. trash truck or dump truck. 

Once again to reiterate - in order for the concept to work, you need cars spaced by much more than 2 seconds, so there is enough interval to merge.  Otherwise all those bypass lane do is slowing down flow upstream.  Usually cars pass intersection at much smaller intervals making those lanes meaningless. Some limited visibility or uphill turns may use the concept, though.   

Quote from: kalvado on October 02, 2016, 09:25:50 PM

Quote from: UCFKnights on October 02, 2016, 08:32:12 PM
For those early mergers, I'm curious what you all think of the frequent expansion of roads at "choke points" only to return to the smaller size right after them. Should we not use the expansions designed to alleviate traffic?

For example, when too many people are trying to turn left onto a road or highway, they frequently install a second left turn lane and a few hundred feet of a second lane on the road to the left to allow people to merge without requiring the left turn signal to be green and impeding the opposing thru traffic for so long?

Also, I know in Palm Beach County, they frequently install a 2nd or 3rd lane for a few hundred feet before a busy intersection only for it to end a few hundred feet after, so people can "skip the line" and not get stuck missing a light cycle. Doing this seems to successfully allow the road to handle much more traffic without the expense of expanding the entire road to 3 lanes, such as if you look at eastbound Clint Moore here: https://www.google.com/maps/@26.4077098,-80.1464466,195m/data=!3m1!1e3

They usually seem to try to expand all the intersections first to alleviate traffic, and only after that begins to fail, connect the 3rd lanes at the intersections (which also makes that eventual 3rd lane construction much less disruptive, as they don't need to rebuild the intersections at that point). If we're all supposed to early merge, wouldn't we never use these lanes specifically designed for us to enter so we can pass the choke point?

I know what you're talking about - and my feeling is that idea may work, but actual design is usually awful over here.  Of 5 or 6 spots I can think of, only one somewhat works. Well, local road designers are only in third decade of learning curve on the matter...
Overall, for the concept to work as designed, you need vehicles in the "main" lane to pass coke point - intersection or turn - at a rate of 1 car every 4-5 seconds. Looks like even most underpowered US vehicles (and from my observations, Jeep Patriot tends to be the worst among passenger cars) can do less than 3 seconds on level road. Maybe different in more fuel economy - conscious places. So from my experience those lanes can in fact be used only to pass a known slow vehicle - e.g. trash truck or dump truck. 

Once again to reiterate - in order for the concept to work, you need cars spaced by much more than 2 seconds, so there is enough interval to merge.  Otherwise all those bypass lane do is slowing down flow upstream.  Usually cars pass intersection at much smaller intervals making those lanes meaningless. Some limited visibility or uphill turns may use the concept, though.

Even if it causes a slowdown upstream, its past the choke point so the congestion isn't pushed further back. At some of these intersections, before the expansion, during rush hour, it would not be able to clear every vehicle that comes to the light. Once that starts to happen, it gets progressively worse every single light cycle during rush hour... making it worse once people can no longer get into the left or right turn lanes and then it continues to back up further into other intersections. After the small expansion, the light clears all traffic nearly every cycle, and while sometimes upstream of the light at the merge, traffic is slowed down or someone stops in the merge lane, its after the light, and can clear itself after the light is red.

Quote from: UCFKnights on October 02, 2016, 11:22:21 PM
Even if it causes a slowdown upstream, its past the choke point so the congestion isn't pushed further back. At some of these intersections, before the expansion, during rush hour, it would not be able to clear every vehicle that comes to the light. Once that starts to happen, it gets progressively worse every single light cycle during rush hour... making it worse once people can no longer get into the left or right turn lanes and then it continues to back up further into other intersections. After the small expansion, the light clears all traffic nearly every cycle, and while sometimes upstream of the light at the merge, traffic is slowed down or someone stops in the merge lane, its after the light, and can clear itself after the light is red.

Let's not behave like traffic designers, lets talk engineering.
What is the throughput of a single downstream lane during green cycle? what is the throughput of a choke point, what are the limiting factors? Throughput at merge point?
What are the possible  penalties associated with merge - like longer yellow phase to allow cars to vacate intersection?
Is there an advantage or disadvantage  of arranging approach as a wider multilane section, as opposed to a longer turn lane? What is the distance past choke  point required to achieve smooth merge of two dense streams, and would that end up being different from adding extra lane throughout the road?

If I had some time to spare, I would go and take a movie of a busy intersection to show my points a bit better. Without solid numbers, this is all doesn't worth server bandwidth..

Quote from: kalvado on October 02, 2016, 09:25:50 PM

Quote from: UCFKnights on October 02, 2016, 08:32:12 PM
For those early mergers, I'm curious what you all think of the frequent expansion of roads at "choke points" only to return to the smaller size right after them. Should we not use the expansions designed to alleviate traffic?

For example, when too many people are trying to turn left onto a road or highway, they frequently install a second left turn lane and a few hundred feet of a second lane on the road to the left to allow people to merge without requiring the left turn signal to be green and impeding the opposing thru traffic for so long?

Also, I know in Palm Beach County, they frequently install a 2nd or 3rd lane for a few hundred feet before a busy intersection only for it to end a few hundred feet after, so people can "skip the line" and not get stuck missing a light cycle. Doing this seems to successfully allow the road to handle much more traffic without the expense of expanding the entire road to 3 lanes, such as if you look at eastbound Clint Moore here: https://www.google.com/maps/@26.4077098,-80.1464466,195m/data=!3m1!1e3

They usually seem to try to expand all the intersections first to alleviate traffic, and only after that begins to fail, connect the 3rd lanes at the intersections (which also makes that eventual 3rd lane construction much less disruptive, as they don't need to rebuild the intersections at that point). If we're all supposed to early merge, wouldn't we never use these lanes specifically designed for us to enter so we can pass the choke point?

I know what you're talking about - and my feeling is that idea may work, but actual design is usually awful over here.  Of 5 or 6 spots I can think of, only one somewhat works. Well, local road designers are only in third decade of learning curve on the matter...
Overall, for the concept to work as designed, you need vehicles in the "main" lane to pass coke point - intersection or turn - at a rate of 1 car every 4-5 seconds. Looks like even most underpowered US vehicles (and from my observations, Jeep Patriot tends to be the worst among passenger cars) can do less than 3 seconds on level road. Maybe different in more fuel economy - conscious places. So from my experience those lanes can in fact be used only to pass a known slow vehicle - e.g. trash truck or dump truck. 

Once again to reiterate - in order for the concept to work, you need cars spaced by much more than 2 seconds, so there is enough interval to merge.  Otherwise all those bypass lane do is slowing down flow upstream.  Usually cars pass intersection at much smaller intervals making those lanes meaningless. Some limited visibility or uphill turns may use the concept, though.   

In my experiences, too few people use them.  That said, since the lane is often empty, I'll use it and can usually move up several spots, and if I'm lucky, I'll get by the slowpoke car...the one that should have really been using that auxiliary lane in the first place.

The worst thing about the extra lane...those self-righteous drivers who stay in the regular lane of traffic and who think others shouldn't be using it so they tailgate, as if the extra lane is for decorative purposes only. 

Quote from: jeffandnicole on October 03, 2016, 08:33:32 AM

In my experiences, too few people use them.  That said, since the lane is often empty, I'll use it and can usually move up several spots, and if I'm lucky, I'll get by the slowpoke car...the one that should have really been using that auxiliary lane in the first place.

The worst thing about the extra lane...those self-righteous drivers who stay in the regular lane of traffic and who think others shouldn't be using it so they tailgate, as if the extra lane is for decorative purposes only.

Well, if people in main lane can tailgate - it means that a bypass lane is for decorative purposes only. Because whole purpose of that is to supply cars to fill voids in traffic past the choke point. And if there are no voids...

Quote from: kalvado on October 03, 2016, 08:48:35 AM

Quote from: jeffandnicole on October 03, 2016, 08:33:32 AM

In my experiences, too few people use them.  That said, since the lane is often empty, I'll use it and can usually move up several spots, and if I'm lucky, I'll get by the slowpoke car...the one that should have really been using that auxiliary lane in the first place.

The worst thing about the extra lane...those self-righteous drivers who stay in the regular lane of traffic and who think others shouldn't be using it so they tailgate, as if the extra lane is for decorative purposes only.

Well, if people in main lane can tailgate - it means that a bypass lane is for decorative purposes only. Because whole purpose of that is to supply cars to fill voids in traffic past the choke point. And if there are no voids...

There isn't a void because someone is tailgating to eliminate that void.  That doesn't mean the lane isn't needed, and the situation is made worse by someone who is illegally tailgating. 

Besides...that one spot may have been lost, but there's still room in front of and behind other vehicles.

Quote from: jeffandnicole on October 03, 2016, 09:03:39 AM

Quote from: kalvado on October 03, 2016, 08:48:35 AM

Quote from: jeffandnicole on October 03, 2016, 08:33:32 AM

In my experiences, too few people use them.  That said, since the lane is often empty, I'll use it and can usually move up several spots, and if I'm lucky, I'll get by the slowpoke car...the one that should have really been using that auxiliary lane in the first place.

The worst thing about the extra lane...those self-righteous drivers who stay in the regular lane of traffic and who think others shouldn't be using it so they tailgate, as if the extra lane is for decorative purposes only.

Well, if people in main lane can tailgate - it means that a bypass lane is for decorative purposes only. Because whole purpose of that is to supply cars to fill voids in traffic past the choke point. And if there are no voids...

There isn't a void because someone is tailgating to eliminate that void.  That doesn't mean the lane isn't needed, and the situation is made worse by someone who is illegally tailgating. 

Besides...that one spot may have been lost, but there's still room in front of and behind other vehicles.

So get behind that tailgaiting vehicle, what is the problem? There should be a double-long spot behind them. Or if there is no room there as well, and you actually want others to make room for you.. If drivers have to slow down to accommodate traffic from bypass lane - it is likely a net loss for throughput, and decorative lane is just a waste.

Of course, it is nice to be able to jump past a slowpoke - but in a grand scheme of things it is probably insignificant. 

Quote from: kalvado on October 03, 2016, 09:15:25 AM

Quote from: jeffandnicole on October 03, 2016, 09:03:39 AM

Quote from: kalvado on October 03, 2016, 08:48:35 AM

Quote from: jeffandnicole on October 03, 2016, 08:33:32 AM

In my experiences, too few people use them.  That said, since the lane is often empty, I'll use it and can usually move up several spots, and if I'm lucky, I'll get by the slowpoke car...the one that should have really been using that auxiliary lane in the first place.

The worst thing about the extra lane...those self-righteous drivers who stay in the regular lane of traffic and who think others shouldn't be using it so they tailgate, as if the extra lane is for decorative purposes only.

Well, if people in main lane can tailgate - it means that a bypass lane is for decorative purposes only. Because whole purpose of that is to supply cars to fill voids in traffic past the choke point. And if there are no voids...

There isn't a void because someone is tailgating to eliminate that void.  That doesn't mean the lane isn't needed, and the situation is made worse by someone who is illegally tailgating. 

Besides...that one spot may have been lost, but there's still room in front of and behind other vehicles.

So get behind that tailgaiting vehicle, what is the problem? There should be a double-long spot behind them. Or if there is no room there as well, and you actually want others to make room for you.. If drivers have to slow down to accommodate traffic from bypass lane - it is likely a net loss for throughput, and decorative lane is just a waste.

Of course, it is nice to be able to jump past a slowpoke - but in a grand scheme of things it is probably insignificant. 

The problem goes back to post 1 in this thread...how to properly zipper.

Quote from: jeffandnicole on October 03, 2016, 09:17:36 AM

Quote from: kalvado on October 03, 2016, 09:15:25 AM

Quote from: jeffandnicole on October 03, 2016, 09:03:39 AM

Quote from: kalvado on October 03, 2016, 08:48:35 AM

Quote from: jeffandnicole on October 03, 2016, 08:33:32 AM

In my experiences, too few people use them.  That said, since the lane is often empty, I'll use it and can usually move up several spots, and if I'm lucky, I'll get by the slowpoke car...the one that should have really been using that auxiliary lane in the first place.

The worst thing about the extra lane...those self-righteous drivers who stay in the regular lane of traffic and who think others shouldn't be using it so they tailgate, as if the extra lane is for decorative purposes only.

Well, if people in main lane can tailgate - it means that a bypass lane is for decorative purposes only. Because whole purpose of that is to supply cars to fill voids in traffic past the choke point. And if there are no voids...

There isn't a void because someone is tailgating to eliminate that void.  That doesn't mean the lane isn't needed, and the situation is made worse by someone who is illegally tailgating. 

Besides...that one spot may have been lost, but there's still room in front of and behind other vehicles.

So get behind that tailgaiting vehicle, what is the problem? There should be a double-long spot behind them. Or if there is no room there as well, and you actually want others to make room for you.. If drivers have to slow down to accommodate traffic from bypass lane - it is likely a net loss for throughput, and decorative lane is just a waste.

Of course, it is nice to be able to jump past a slowpoke - but in a grand scheme of things it is probably insignificant. 

The problem goes back to post 1 in this thread...how to properly zipper.

You cannot have a cake and eat it too.
There are intervals between cars, 2 seconds or slightly less. And if one lane is able to supply that much traffic, you cannot squeeze in traffic from the second lane.

I bet the way you think about it is "if they slow down a tiny little bit and let me in, nothing will change". Incremental change is not that great - but if you look at the end result, you will see the price to be paid.

Quote from: jeffandnicole on October 03, 2016, 03:06:59 PM

You do understand that these lanes exist, and yes, traffic from the second lane can squeeze in because, as we all know, drivers don't leave 2 second gaps.

In fact, in reference to that, in most cases that's just a suggested safety gap.  I'm not sure if there's any actual law anywhere requiring it.  So, what is tailgating?  Basically, it's in the eye of the beholder.

Many bad things exist in this world - Trump, Billary, cancer and roundabouts just to name a few...
That is not the point, point is if there is any good in existence of those bypass lanes, or bypass lanes belong to the same group. 

Previously I showed actual studies - highway lanes choke at 2000 VPH, or 1 vehicle every 1.8 seconds. A little bit more, a little bit less - still works about the same way, probably lower for streets.
So question is: what is the actual rate of vehicle flow through the intersection compared to flow in a straight lane downstream, and how long does it take for a consistent flow to establish. I don't have any data handy. Of course, I can just park a car with dashcam running near the intersection for 15-20 minutes, but I am lazy...
But my impression is that traffic through the single-lane intersection still flows in a fairly solid formation quarter mile past the light. Solid as in no easy merge spots, and fairly dense spacing. That would be pretty much the answer.

Or, if you will, a question is how bad of a choke point an average intersection is, and how fast can cars depart from a stopped lane.
My impression, once again, is that once cars further behind start moving, entrance rate is approximately the same as lane flow rate.

Quote from: texaskdog on September 05, 2016, 09:30:22 AM
Zipper merging only works if you have two lanes merging into the middle, and then traffic moves where it needs to.  I hate the budgers so much, the ones who do it every day in non-construction zones

I agree on that (merge into the middle straddling both lanes), and think a zipper merge should require flashing (diagonal down) yellow arrows on both sides of the single open lane to indicate that traffic should alternate at the zipper point.  I have yet to see any zipper merge use the latter idea.

With some trepidation, I thought I'd bump this topic since it seems to be in vogue these days, with various articles on the subject currently going around social media.

Most of these articles contain what I see as a fatal flaw: they only present the issue in terms of two possible options. One is to merge early and be courteous, and the other is to be a jerk, but correct. So, some drivers reading these articles will undoubtedly decide to merge early anyhow, knowing that it's not the best way, because they don't want to appear discourteous. But one of the articles links to this MoDOT page (http://www.modot.org/workzones/ZipperMerge.htm), which seems to do the best job at explaining the situation clearly and in full.

I also have to wonder, to what extent would it help simply to deprecate signage that refers to either the right or left lane ending (regardless of the actual configuration), to enforce the idea that there's no "correct" lane to be in and thus discourage early merging in case where it's not appropriate, as well as to eliminate the basis for vigilanteism?

Quote from: empirestate on July 14, 2017, 10:41:20 AM
I also have to wonder, to what extent would it help simply to deprecate signage that refers to either the right or left lane ending (regardless of the actual configuration), to enforce the idea that there's no "correct" lane to be in and thus discourage early merging in case where it's not appropriate, as well as to eliminate the basis for vigilanteism?

As I've probably said before, for the most part, NJDOT will generally only sign lane closures 1,500 feet in advance (and I've seen no more than 1,000 feet in advance too).  The most you'll get is about 1/4 mile of unused lane.

It's hard to say that there's no one particular lane that's ending, because it would invite confusion.   It's rare to be able to have an equal merge because you somehow have to instruct people to ride over the line, not between the lines, which motorists aren't used to doing.  There are people that refuse to cross a solid line even when there's an obstruction in the road, and they squeeze as best they can between the obstruction and the solid line.

In my mind, the concept of the zipper merge works best if you have frequent signs that say "Use Both Lanes Up To Merge Point" and then signs at the merge point instructing drivers to take turns advancing into the open lane.

Quote from: jeffandnicole on July 14, 2017, 10:55:22 AM
It's hard to say that there's no one particular lane that's ending, because it would invite confusion.   It's rare to be able to have an equal merge because you somehow have to instruct people to ride over the line, not between the lines, which motorists aren't used to doing.  There are people that refuse to cross a solid line even when there's an obstruction in the road, and they squeeze as best they can between the obstruction and the solid line.

Not sure I follow you; what do you mean by "riding over the line"? What I'm thinking of would only involved changing the wording on signs.

Quote from: empirestate on July 14, 2017, 10:41:20 AM
With some trepidation, I thought I'd bump this topic since it seems to be in vogue these days, with various articles on the subject currently going around social media.

Most of these articles contain what I see as a fatal flaw: they only present the issue in terms of two possible options. One is to merge early and be courteous, and the other is to be a jerk, but correct. So, some drivers reading these articles will undoubtedly decide to merge early anyhow, knowing that it's not the best way, because they don't want to appear discourteous. But one of the articles links to this MoDOT page (http://www.modot.org/workzones/ZipperMerge.htm), which seems to do the best job at explaining the situation clearly and in full.

I also have to wonder, to what extent would it help simply to deprecate signage that refers to either the right or left lane ending (regardless of the actual configuration), to enforce the idea that there's no "correct" lane to be in and thus discourage early merging in case where it's not appropriate, as well as to eliminate the basis for vigilanteism?

Fatal flaw of the article is saying "capacity is maximized" right on a picture. I suspect "safety is increased" is also wrong. 

Quote from: kalvado on July 14, 2017, 12:58:38 PM
Fatal flaw of the article is saying "capacity is maximized" right on a picture. I suspect "safety is increased" is also wrong.

Based on what?

Quote from: jakeroot on July 14, 2017, 02:37:41 PM

Quote from: kalvado on July 14, 2017, 12:58:38 PM
Fatal flaw of the article is saying "capacity is maximized" right on a picture. I suspect "safety is increased" is also wrong.

Based on what?

Based on all discussion above along with common sense.
Otherwise, a peer reviewed research paper comparing two merge modes may be an argument, but - as always - no time to learn how to do things right and waste money on research, we need just finalize the budget.

Quote from: empirestate on July 14, 2017, 11:44:44 AM

Quote from: jeffandnicole on July 14, 2017, 10:55:22 AM
It's hard to say that there's no one particular lane that's ending, because it would invite confusion.   It's rare to be able to have an equal merge because you somehow have to instruct people to ride over the line, not between the lines, which motorists aren't used to doing.  There are people that refuse to cross a solid line even when there's an obstruction in the road, and they squeeze as best they can between the obstruction and the solid line.

Not sure I follow you; what do you mean by "riding over the line"? What I'm thinking of would only involved changing the wording on signs.

If you have two lanes, one lane *has* to merge into the other.  Is the right merging into the left, or left merging into the right?  You can't just post "lane ends" signage for both lanes.  Or no signage at all. 

If there's two lanes, and they both have an equal merge removing half their lane, you'll be driving over the center line that divides the two lanes.

Now, I'm thinking construction based, where the lane merge is temporary.  If you're thinking of a permanent lane ending, then you definitely need some clarification, because for the most part traffic will be moving fine.  It's not like there's going to be a 24 hour backup where a zipper merge is always necessary.

Quote from: kalvado on July 14, 2017, 03:13:47 PM

Quote from: jakeroot on July 14, 2017, 02:37:41 PM

Quote from: kalvado on July 14, 2017, 12:58:38 PM
Fatal flaw of the article is saying "capacity is maximized" right on a picture. I suspect "safety is increased" is also wrong.

Based on what?

Based on all discussion above along with common sense.

Oh, right. This is the sixth page of this discussion.

No need to go around and around again. We know each other's opinions on the matter.

Quote from: jeffandnicole on July 14, 2017, 03:15:47 PM

Quote from: empirestate on July 14, 2017, 11:44:44 AM

Quote from: jeffandnicole on July 14, 2017, 10:55:22 AM
It's hard to say that there's no one particular lane that's ending, because it would invite confusion.   It's rare to be able to have an equal merge because you somehow have to instruct people to ride over the line, not between the lines, which motorists aren't used to doing.  There are people that refuse to cross a solid line even when there's an obstruction in the road, and they squeeze as best they can between the obstruction and the solid line.

Not sure I follow you; what do you mean by "riding over the line"? What I'm thinking of would only involved changing the wording on signs.

If you have two lanes, one lane *has* to merge into the other.  Is the right merging into the left, or left merging into the right?  You can't just post "lane ends" signage for both lanes.  Or no signage at all.

That's what I'm not following–why not? Whichever lane it is that's actually closed, you just don't mention that on signage; instead you'd just say "lanes merge ahead" (or similar). You wouldn't have to configure the lanes any different physically, in my scenario.

QuoteIf there's two lanes, and they both have an equal merge removing half their lane, you'll be driving over the center line that divides the two lanes.

I see. Yeah, that's not part of what I'm wondering about; I'm talking only about changing the wording on signs. Now, a logical next step in the discussion could involve actually changing the physical configuration, which I think would necessarily involve temporary re-striping to avoid what you describe. But I'm not quite at that step.

QuoteNow, I'm thinking construction based, where the lane merge is temporary.  If you're thinking of a permanent lane ending, then you definitely need some clarification, because for the most part traffic will be moving fine.  It's not like there's going to be a 24 hour backup where a zipper merge is always necessary.

Construction based, yeah, or any scenario where traffic is slowed such that a zipper merge is appropriate. Maybe you could imagine a permanent lane drop, with changeable signage that reflects current traffic speeds–but again, I'm not quite that far along in my hypothesis yet.

In most cases, one lane ends and it is subservient to the other.  If you are in the lane that ends you must safely merge in and there is no requirement for traffic in the other lane to let you in.  This of course, is standard at most freeway entrances and is shown by signs that denote right lane ends (or left lane ends)

The alternate merge, or zipper merge, is great and is designed that neither lane has priority over the other.  You see this on the NJ turnpike where both roadways merge together and the right lane of the car lanes merges with the left lane of the car-truck-bus lanes.  I also see this regularly on I-70 merging into I-695 north near Baltimore.  The alternate merge works great here because it is carefully worded and everyone understands what to do.

Quote from: mrsman on July 19, 2017, 11:12:00 PM
In most cases, one lane ends and it is subservient to the other.  If you are in the lane that ends you must safely merge in and there is no requirement for traffic in the other lane to let you in.  This of course, is standard at most freeway entrances and is shown by signs that denote right lane ends (or left lane ends)

So my question is simply whether, in work zones especially, it makes sense NOT to have signs that denotes which lane ends, and simply to state that the lanes merge together. This being one step in a process, mind you, not an entire solution.



iPhone

Quote from: empirestate on July 21, 2017, 01:01:00 AM

Quote from: mrsman on July 19, 2017, 11:12:00 PM
In most cases, one lane ends and it is subservient to the other.  If you are in the lane that ends you must safely merge in and there is no requirement for traffic in the other lane to let you in.  This of course, is standard at most freeway entrances and is shown by signs that denote right lane ends (or left lane ends)

So my question is simply whether, in work zones especially, it makes sense NOT to have signs that denotes which lane ends, and simply to state that the lanes merge together. This being one step in a process, mind you, not an entire solution.



iPhone

Another solution might be to put cones between the lane that ends and the lane that it merges into for a certain distance up until just before the closure point.  That way you won't have cars in the lane that doesn't close coming to a stop so that other cars can merge in 2 miles before the closure and then have perceived "cutters" zoom along at 70 until just before the merge and expect to be let in by the vehicles they just passed.

Quote from: ParrDa on September 16, 2017, 12:09:37 AM

An aspect of this topic that has not been discussed...
What if an exit ramp is the choke point?
How should three lanes worth of freeway traffic start forming a single file line (while allowing the occasional thru car to go by at speed)?

Sounds like a question for whichever dipshit designed the Hillside Strangler at I-88 and I-290 by Chicago.

Based on the message boards, it appears DuPage County, Illinois is trying a zipper merge on Winfield Road for bridge work at Mack Road.

Yesterday we encountered this sign on I-70 passing Terre Haute, Indiana. Wasn't a true zipper merge because the left lane ultimately ended more than a mile further down the road, but the sign is clear enough, right? Not to the people on I-70. Almost everyone panicked and moved over a mile in advance of the merge point. On the plus side for us, that meant we sailed past a long line of cars because I merge at the end just like the sign said (only one guy from Oklahoma seemed to take umbrage, but that was right at the end anyway).

(https://uploads.tapatalk-cdn.com/20171016/b28d4d998e486ed43b288c0ee080b5ba.jpg)

^^ During our recent trip on SR 37 near Bloomington, IN (on the I-69 upgrade), I saw signs like this. I had never before seen signs instructing drivers to zipper merge. The usual practice in Indiana has been to merge soon after the first signs warning of the lane closure.

The signs on 37 seemed to have some effect, but as 1995hoo says most drivers merged near the first warning.

SR 37 also had signs closer to the lane closure saying "MERGE HERE" or words to that effect. Few cars made it that far before merging.

I do wish the MUTCD would scale back regulations that require X-amount of warning before lanes end or merge. If we didn't advertise lane endings so early, we might get more zippering.

Quote from: jakeroot on October 16, 2017, 03:58:52 PM
I do wish the MUTCD would scale back regulations that require X-amount of warning before lanes end or merge. If we didn't advertise lane endings so early, we might get more zippering.

And point of all that being?...

Quote from: kalvado on October 16, 2017, 04:22:56 PM

Quote from: jakeroot on October 16, 2017, 03:58:52 PM
I do wish the MUTCD would scale back regulations that require X-amount of warning before lanes end or merge. If we didn't advertise lane endings so early, we might get more zippering.

And point of all that being?...

I'm not going through this again. You know we have a difference of opinion on merging.

Quote from: jakeroot on October 16, 2017, 04:25:36 PM

Quote from: kalvado on October 16, 2017, 04:22:56 PM

Quote from: jakeroot on October 16, 2017, 03:58:52 PM
I do wish the MUTCD would scale back regulations that require X-amount of warning before lanes end or merge. If we didn't advertise lane endings so early, we might get more zippering.

And point of all that being?...

I'm not going through this again. You know we have a difference of opinion on merging.

I still wonder if "better use of road capacity" means something more than " blahblahblah in lalaland" to anyone talking about the subject..

Quote from: kalvado on October 16, 2017, 04:27:42 PM

Quote from: jakeroot on October 16, 2017, 04:25:36 PM

Quote from: kalvado on October 16, 2017, 04:22:56 PM

Quote from: jakeroot on October 16, 2017, 03:58:52 PM
I do wish the MUTCD would scale back regulations that require X-amount of warning before lanes end or merge. If we didn't advertise lane endings so early, we might get more zippering.

And point of all that being?...

I'm not going through this again. You know we have a difference of opinion on merging.

I still wonder if "better use of road capacity" means something more than " blahblahblah in lalaland" to anyone talking about the subject..

It probably means something in construction zones, which are often more congested due to lane-drops, lower limits and narrowed lanes. Anything to improve capacity, you know?

Quote from: jakeroot on October 16, 2017, 04:25:36 PM
not going through this again

I down with this.

Quote from: jakeroot on October 16, 2017, 04:35:18 PM

Quote from: kalvado on October 16, 2017, 04:27:42 PM

Quote from: jakeroot on October 16, 2017, 04:25:36 PM

Quote from: kalvado on October 16, 2017, 04:22:56 PM

Quote from: jakeroot on October 16, 2017, 03:58:52 PM
I do wish the MUTCD would scale back regulations that require X-amount of warning before lanes end or merge. If we didn't advertise lane endings so early, we might get more zippering.

And point of all that being?...

I'm not going through this again. You know we have a difference of opinion on merging.

I still wonder if "better use of road capacity" means something more than " blahblahblah in lalaland" to anyone talking about the subject..

It probably means something in construction zones, which are often more congested due to lane-drops, lower limits and narrowed lanes. Anything to improve capacity, you know?

Well, before going to matters as complicated as "construction zone",  and "congestion", defining "capacity" may be a good step forward.

Quote from: kalvado on October 16, 2017, 04:57:58 PM
Well, before going to matters as complicated as "construction zone",  and "congestion", defining "capacity" may be a good step forward.

Vehicles per hour DOES NOT EQUAL amount of space occupied by vehicles at any given time.
Your definition of capacity scales upward with the amount of space occupied by vehicles.  Jake's definition (and mine) relates to the number of vehicles which can pass through a point on the roadway during a unit of time.  These definitions are not directly related.  Roadway capacity is measured in vehicles per hour, not vehicles per square yard.

Quote from: paulthemapguy on October 16, 2017, 05:45:08 PM

Quote from: kalvado on October 16, 2017, 04:57:58 PM
Well, before going to matters as complicated as "construction zone",  and "congestion", defining "capacity" may be a good step forward.

Vehicles per hour DOES NOT EQUAL amount of space occupied by vehicles at any given time.
Your definition of capacity scales upward with the amount of space occupied by vehicles.  Jake's definition (and mine) relates to the number of vehicles which can pass through a point on the roadway during a unit of time.  These definitions are not directly related.  Roadway capacity is measured in vehicles per hour, not vehicles per square yard.

You'll be surprised how many people on this forum do disagree with VPH metrics..  :bigass:
But once you adopt that metric, entire zipper concept falls apart.

Back when I was in high school, they built a new building and did not expand the parking lot (parking capacity was not a real issue, before the expansion the lot would NEVER come close to filling up). After this, they ran into an issue where at pickup time, it would back up onto the main road and cause all sorts of problems, once it backed up onto it, it'd back up into other intersections and create gridlock. To try to solve this, they converted the parking lanes leading to the pickup area to be one way and "two lanes", and put signs at the beginning of this they put a sign "USE BOTH LANES" and at the end of it they put a sign "MERGE HERE - ALTERNATE LANES". The parents mostly ignored the signs, so they assumed they didn't see them and made additional signs, and installed 2 more of the same signs at the beginning and end, except one on the right side of the road, one in the center between the two lanes, and on on the left side. The parents still ignored the signs... they then decided to station the school officer by the sign to help people alternate between the two lanes... as soon as people were 50 feet past the person, they'd try to move back to the right lane way before the end of it. They added "STAY IN YOUR LANE" signs after the USE BOTH LANE signs and they didn't help. They started laying out cones to keep people in the lanes until the end which seemed effective, but any time someone wasn't out to direct the traffic, almost everyone would inevitably end up in the right lane and it'd backup onto the main road. When I asked parents why they wouldn't use the left lane, they said it wasn't going to make anything any faster, the pickup area only moves so fast, and they needed to be in the right lane for pickup anyways.

The length of the queue wasn't really off by too much... if they got about 10-15 cars into the left lane and people to pull forward and not leave multiple car lengths, the entire queue would be within the school property and it'd prevent the backups onto other roads. After 2 or 3 years of this, they redid the parking lot to add an extra loop to the queue so the cars could remain in a single lane.

So whats the point of this story? Its literally demonstrating the purpose of the zipper merge. So back to the topic:

QuoteYou'll be surprised how many people on this forum do disagree with VPH metrics..  :bigass:
But once you adopt that metric, entire zipper concept falls apart.

Thats because VPH is the WRONG metric of what the zipper concept is trying to solve. The VPH through the merge point is ultimately what the road is capable of AFTER THE MERGE IS OVER, regardless of where the the merge point is.... that is the bottleneck and the zipper merge isn't going to improve that.

The proper metric would be linear feet of congestion. Does the zipper merge effectively decrease the number of linear feet of congestion? Because if an early merge is causing a 5 mile backup and switching it to a zipper merge reduces the backup by 1 mile, that means that anyone exiting in that one mile that the zipper merge reduces the congestion will now no longer experience any congestion, have their travel time cut down, and reduce the congestion for everyone by getting less people in the congested areas.

If you insist on using VPH as your metric, you actually can use that as well.... you just need to make sure you use it at the right spot on the road. The VPH metric will only be increased by measuring before each exit prior to the merge point. The VPH will mostly be increased at the first exit after the congestion would otherwise begin, with smaller increases as you get closer to the zipper merge. Using VPH close to the actual merge point is a meaningless metric, thats not where the zipper merge is designed to increase it.

When people fail to use the road capacity, the length of congestion increases. That is the metric that you are supposed to be using

Quote from: UCFKnights on October 16, 2017, 08:33:50 PM
Back when I was in high school, they built a new building and did not expand the parking lot (parking capacity was not a real issue, before the expansion the lot would NEVER come close to filling up). After this, they ran into an issue where at pickup time, it would back up onto the main road and cause all sorts of problems, once it backed up onto it, it'd back up into other intersections and create gridlock. To try to solve this, they converted the parking lanes leading to the pickup area to be one way and "two lanes", and put signs at the beginning of this they put a sign "USE BOTH LANES" and at the end of it they put a sign "MERGE HERE - ALTERNATE LANES". The parents mostly ignored the signs, so they assumed they didn't see them and made additional signs, and installed 2 more of the same signs at the beginning and end, except one on the right side of the road, one in the center between the two lanes, and on on the left side. The parents still ignored the signs... they then decided to station the school officer by the sign to help people alternate between the two lanes... as soon as people were 50 feet past the person, they'd try to move back to the right lane way before the end of it. They added "STAY IN YOUR LANE" signs after the USE BOTH LANE signs and they didn't help. They started laying out cones to keep people in the lanes until the end which seemed effective, but any time someone wasn't out to direct the traffic, almost everyone would inevitably end up in the right lane and it'd backup onto the main road. When I asked parents why they wouldn't use the left lane, they said it wasn't going to make anything any faster, the pickup area only moves so fast, and they needed to be in the right lane for pickup anyways.

The length of the queue wasn't really off by too much... if they got about 10-15 cars into the left lane and people to pull forward and not leave multiple car lengths, the entire queue would be within the school property and it'd prevent the backups onto other roads. After 2 or 3 years of this, they redid the parking lot to add an extra loop to the queue so the cars could remain in a single lane.

So whats the point of this story? Its literally demonstrating the purpose of the zipper merge. So back to the topic:

QuoteYou'll be surprised how many people on this forum do disagree with VPH metrics..  :bigass:
But once you adopt that metric, entire zipper concept falls apart.

Thats because VPH is the WRONG metric of what the zipper concept is trying to solve. The VPH through the merge point is ultimately what the road is capable of AFTER THE MERGE IS OVER, regardless of where the the merge point is.... that is the bottleneck and the zipper merge isn't going to improve that.

The proper metric would be linear feet of congestion. Does the zipper merge effectively decrease the number of linear feet of congestion? Because if an early merge is causing a 5 mile backup and switching it to a zipper merge reduces the backup by 1 mile, that means that anyone exiting in that one mile that the zipper merge reduces the congestion will now no longer experience any congestion, have their travel time cut down, and reduce the congestion for everyone by getting less people in the congested areas.

If you insist on using VPH as your metric, you actually can use that as well.... you just need to make sure you use it at the right spot on the road. The VPH metric will only be increased by measuring before each exit prior to the merge point. The VPH will mostly be increased at the first exit after the congestion would otherwise begin, with smaller increases as you get closer to the zipper merge. Using VPH close to the actual merge point is a meaningless metric, thats not where the zipper merge is designed to increase it.

When people fail to use the road capacity, the length of congestion increases. That is the metric that you are supposed to be using

Good example, thank you.
However - and we discussed that somewhere upstream - such approach is relevant in limited situations only. Zipper concept is pushed mostly for highway traffic. Then in order for all that to be relevant, an exit has to be close enough to the bottleneck; and traffic volume has to be such that an extra half a mile of jam - due to early merge a mile before the bottleneck makes a difference; a bit more traffic - and exit blocked anyway; a bit less - and exit is free anyway.
Probably can be important in dense cities - NYC and LA...

Quote from: kalvado on October 17, 2017, 08:14:22 AM

Quote from: UCFKnights on October 16, 2017, 08:33:50 PM
Back when I was in high school, they built a new building and did not expand the parking lot (parking capacity was not a real issue, before the expansion the lot would NEVER come close to filling up). After this, they ran into an issue where at pickup time, it would back up onto the main road and cause all sorts of problems, once it backed up onto it, it'd back up into other intersections and create gridlock. To try to solve this, they converted the parking lanes leading to the pickup area to be one way and "two lanes", and put signs at the beginning of this they put a sign "USE BOTH LANES" and at the end of it they put a sign "MERGE HERE - ALTERNATE LANES". The parents mostly ignored the signs, so they assumed they didn't see them and made additional signs, and installed 2 more of the same signs at the beginning and end, except one on the right side of the road, one in the center between the two lanes, and on on the left side. The parents still ignored the signs... they then decided to station the school officer by the sign to help people alternate between the two lanes... as soon as people were 50 feet past the person, they'd try to move back to the right lane way before the end of it. They added "STAY IN YOUR LANE" signs after the USE BOTH LANE signs and they didn't help. They started laying out cones to keep people in the lanes until the end which seemed effective, but any time someone wasn't out to direct the traffic, almost everyone would inevitably end up in the right lane and it'd backup onto the main road. When I asked parents why they wouldn't use the left lane, they said it wasn't going to make anything any faster, the pickup area only moves so fast, and they needed to be in the right lane for pickup anyways.

The length of the queue wasn't really off by too much... if they got about 10-15 cars into the left lane and people to pull forward and not leave multiple car lengths, the entire queue would be within the school property and it'd prevent the backups onto other roads. After 2 or 3 years of this, they redid the parking lot to add an extra loop to the queue so the cars could remain in a single lane.

So whats the point of this story? Its literally demonstrating the purpose of the zipper merge. So back to the topic:

QuoteYou'll be surprised how many people on this forum do disagree with VPH metrics..  :bigass:
But once you adopt that metric, entire zipper concept falls apart.

Thats because VPH is the WRONG metric of what the zipper concept is trying to solve. The VPH through the merge point is ultimately what the road is capable of AFTER THE MERGE IS OVER, regardless of where the the merge point is.... that is the bottleneck and the zipper merge isn't going to improve that.

The proper metric would be linear feet of congestion. Does the zipper merge effectively decrease the number of linear feet of congestion? Because if an early merge is causing a 5 mile backup and switching it to a zipper merge reduces the backup by 1 mile, that means that anyone exiting in that one mile that the zipper merge reduces the congestion will now no longer experience any congestion, have their travel time cut down, and reduce the congestion for everyone by getting less people in the congested areas.

If you insist on using VPH as your metric, you actually can use that as well.... you just need to make sure you use it at the right spot on the road. The VPH metric will only be increased by measuring before each exit prior to the merge point. The VPH will mostly be increased at the first exit after the congestion would otherwise begin, with smaller increases as you get closer to the zipper merge. Using VPH close to the actual merge point is a meaningless metric, thats not where the zipper merge is designed to increase it.

When people fail to use the road capacity, the length of congestion increases. That is the metric that you are supposed to be using

Good example, thank you.
However - and we discussed that somewhere upstream - such approach is relevant in limited situations only. Zipper concept is pushed mostly for highway traffic. Then in order for all that to be relevant, an exit has to be close enough to the bottleneck; and traffic volume has to be such that an extra half a mile of jam - due to early merge a mile before the bottleneck makes a difference; a bit more traffic - and exit blocked anyway; a bit less - and exit is free anyway.
Probably can be important in dense cities - NYC and LA...

It's not just exits.  For example, if there is a curve on the highway 2 miles before the work zone, which creates a dangerous situation if traffic backs up to just after the curve; and a zipper merge helps prevent backups from reaching that curve, then I'd say the zipper merge is preferable.

This argument of zipper merges are always preferable...or never preferable, is missing the point.  There are situations for one vs the other.  The difference is specific to roadway geometry (curves, exits, etc) and volume.  A lower volume highway and simple geometry, zipper merge is probably useless; early merge is probably preferable. High volume road, complex geometry; zipper merge is preferable assuming all users understand the concept.

Quote from: jemacedo9 on October 17, 2017, 08:51:30 AM
It's not just exits.  For example, if there is a curve on the highway 2 miles before the work zone, which creates a dangerous situation if traffic backs up to just after the curve; and a zipper merge helps prevent backups from reaching that curve, then I'd say the zipper merge is preferable.

And this is an example of bad argument, to the point of getting F for the test just for that thing alone for inability to see bigger picture.
Once there is a backup, there will be a slowdown point. If it falls into the curve, right before or right after  is more or less pure luck. This is more of an arguments towards how speed should be controlled to enable safe stopping even in complex geometry - but nothing else

Quote from: kalvado on October 17, 2017, 08:14:22 AM

Quote from: UCFKnights on October 16, 2017, 08:33:50 PM
Back when I was in high school, they built a new building and did not expand the parking lot (parking capacity was not a real issue, before the expansion the lot would NEVER come close to filling up). After this, they ran into an issue where at pickup time, it would back up onto the main road and cause all sorts of problems, once it backed up onto it, it'd back up into other intersections and create gridlock. To try to solve this, they converted the parking lanes leading to the pickup area to be one way and "two lanes", and put signs at the beginning of this they put a sign "USE BOTH LANES" and at the end of it they put a sign "MERGE HERE - ALTERNATE LANES". The parents mostly ignored the signs, so they assumed they didn't see them and made additional signs, and installed 2 more of the same signs at the beginning and end, except one on the right side of the road, one in the center between the two lanes, and on on the left side. The parents still ignored the signs... they then decided to station the school officer by the sign to help people alternate between the two lanes... as soon as people were 50 feet past the person, they'd try to move back to the right lane way before the end of it. They added "STAY IN YOUR LANE" signs after the USE BOTH LANE signs and they didn't help. They started laying out cones to keep people in the lanes until the end which seemed effective, but any time someone wasn't out to direct the traffic, almost everyone would inevitably end up in the right lane and it'd backup onto the main road. When I asked parents why they wouldn't use the left lane, they said it wasn't going to make anything any faster, the pickup area only moves so fast, and they needed to be in the right lane for pickup anyways.

The length of the queue wasn't really off by too much... if they got about 10-15 cars into the left lane and people to pull forward and not leave multiple car lengths, the entire queue would be within the school property and it'd prevent the backups onto other roads. After 2 or 3 years of this, they redid the parking lot to add an extra loop to the queue so the cars could remain in a single lane.

So whats the point of this story? Its literally demonstrating the purpose of the zipper merge. So back to the topic:

QuoteYou'll be surprised how many people on this forum do disagree with VPH metrics..  :bigass:
But once you adopt that metric, entire zipper concept falls apart.

Thats because VPH is the WRONG metric of what the zipper concept is trying to solve. The VPH through the merge point is ultimately what the road is capable of AFTER THE MERGE IS OVER, regardless of where the the merge point is.... that is the bottleneck and the zipper merge isn't going to improve that.

The proper metric would be linear feet of congestion. Does the zipper merge effectively decrease the number of linear feet of congestion? Because if an early merge is causing a 5 mile backup and switching it to a zipper merge reduces the backup by 1 mile, that means that anyone exiting in that one mile that the zipper merge reduces the congestion will now no longer experience any congestion, have their travel time cut down, and reduce the congestion for everyone by getting less people in the congested areas.

If you insist on using VPH as your metric, you actually can use that as well.... you just need to make sure you use it at the right spot on the road. The VPH metric will only be increased by measuring before each exit prior to the merge point. The VPH will mostly be increased at the first exit after the congestion would otherwise begin, with smaller increases as you get closer to the zipper merge. Using VPH close to the actual merge point is a meaningless metric, thats not where the zipper merge is designed to increase it.

When people fail to use the road capacity, the length of congestion increases. That is the metric that you are supposed to be using

Good example, thank you.
However - and we discussed that somewhere upstream - such approach is relevant in limited situations only. Zipper concept is pushed mostly for highway traffic. Then in order for all that to be relevant, an exit has to be close enough to the bottleneck; and traffic volume has to be such that an extra half a mile of jam - due to early merge a mile before the bottleneck makes a difference; a bit more traffic - and exit blocked anyway; a bit less - and exit is free anyway.
Probably can be important in dense cities - NYC and LA...

I can see the same thing in Orlando every day, and when I was in South Florida, there too (although people there were better about zipper merging). And Jacksonville too. Infact, almost anywhere that isn't rural with exits many miles a part. The thing is, just like my school example, where once the traffic backs up to the main road, even though its only a few cars in the main road, you're now blocking all the people who are not even part of the merge, and they have to be added to the queue, which led to it backing up into other intersections, and now creating congestion on other roads. Once you block that first exit, or cause the entry ramp onto the highway to back up onto another road, the growth of the congestion isn't linear. Now you have to add everyone who wants to take that first exit to the congestion, in addition to the upstream problem. Which causes it to block 2 exits back, and so on.

People seriously underestimate how much of a difference small pieces of road and their utilization can make to capacity and congestion.

The throughput at the bottleneck remains the same either way, right?  All that's really changing with a zipper merge is that, between the two lanes, more storage is accomplished with the zipper merge.  Plus it also discourages the mentality that "this is my lane, dammit, so you can just sit there and wait because you didn't move over when I think you should have."

I've seen a lot of argument as to why a zipper merge might not actually be benificial, but where are the arguments that it's detrimental?

Quote from: kphoger on October 17, 2017, 10:24:44 AM
The throughput at the bottleneck remains the same either way, right?  All that's really changing with a zipper merge is that, between the two lanes, more storage is accomplished with the zipper merge.  Plus it also discourages the mentality that "this is my lane, dammit, so you can just sit there and wait because you didn't move over when I think you should have."

I've seen a lot of argument as to why a zipper merge might not actually be benificial, but where are the arguments that it's detrimental?

Actually zipper slightly  reduces throughput at the bottleneck. Having to do two things - lane change and accelerate, while making sure driver in the other lane actually doing what they are supposed to do - will slow down entry into the limiting point.
And well, legality of zipper approach is quite questionable.

Quote from: UCFKnights on October 17, 2017, 09:43:48 AM
I can see the same thing in Orlando every day, and when I was in South Florida, there too (although people there were better about zipper merging). And Jacksonville too. Infact, almost anywhere that isn't rural with exits many miles a part. The thing is, just like my school example, where once the traffic backs up to the main road, even though its only a few cars in the main road, you're now blocking all the people who are not even part of the merge, and they have to be added to the queue, which led to it backing up into other intersections, and now creating congestion on other roads. Once you block that first exit, or cause the entry ramp onto the highway to back up onto another road, the growth of the congestion isn't linear. Now you have to add everyone who wants to take that first exit to the congestion, in addition to the upstream problem. Which causes it to block 2 exits back, and so on.

People seriously underestimate how much of a difference small pieces of road and their utilization can make to capacity and congestion.

As discussed upstream, blocking entry ramp may actually be beneficial as it encourages using alternative roads.  Those not using GPS software may miss the message, though..

Quote from: kalvado on October 17, 2017, 10:30:50 AM

Quote from: kphoger on October 17, 2017, 10:24:44 AM
The throughput at the bottleneck remains the same either way, right?  All that's really changing with a zipper merge is that, between the two lanes, more storage is accomplished with the zipper merge.  Plus it also discourages the mentality that "this is my lane, dammit, so you can just sit there and wait because you didn't move over when I think you should have."

I've seen a lot of argument as to why a zipper merge might not actually be benificial, but where are the arguments that it's detrimental?

Actually zipper slightly  reduces throughput at the bottleneck. Having to do two things - lane change and accelerate, while making sure driver in the other lane actually doing what they are supposed to do - will slow down entry into the limiting point.
And well, legality of zipper approach is quite questionable.

It's my understanding that, if done correctly, the zipper merge should eliminate the existence of an "other lane".  That is, both lanes are equally responsible for merging and letting in.  That's what taking turns means.

Quote from: kphoger on October 17, 2017, 10:47:53 AM

Quote from: kalvado on October 17, 2017, 10:30:50 AM

Quote from: kphoger on October 17, 2017, 10:24:44 AM
The throughput at the bottleneck remains the same either way, right?  All that's really changing with a zipper merge is that, between the two lanes, more storage is accomplished with the zipper merge.  Plus it also discourages the mentality that "this is my lane, dammit, so you can just sit there and wait because you didn't move over when I think you should have."

I've seen a lot of argument as to why a zipper merge might not actually be benificial, but where are the arguments that it's detrimental?

Actually zipper slightly  reduces throughput at the bottleneck. Having to do two things - lane change and accelerate, while making sure driver in the other lane actually doing what they are supposed to do - will slow down entry into the limiting point.
And well, legality of zipper approach is quite questionable.

It's my understanding that, if done correctly, the zipper merge should eliminate the existence of an "other lane".  That is, both lanes are equally responsible for merging and letting in.  That's what taking turns means.

What do you mean by "eliminating"? Would bulldozers move in and remove the pavement - or do you mean something else?

Quote from: kalvado on October 17, 2017, 12:01:04 PM

Quote from: kphoger on October 17, 2017, 10:47:53 AM

Quote from: kalvado on October 17, 2017, 10:30:50 AM

Quote from: kphoger on October 17, 2017, 10:24:44 AM
The throughput at the bottleneck remains the same either way, right?  All that's really changing with a zipper merge is that, between the two lanes, more storage is accomplished with the zipper merge.  Plus it also discourages the mentality that "this is my lane, dammit, so you can just sit there and wait because you didn't move over when I think you should have."

I've seen a lot of argument as to why a zipper merge might not actually be benificial, but where are the arguments that it's detrimental?

Actually zipper slightly  reduces throughput at the bottleneck. Having to do two things - lane change and accelerate, while making sure driver in the other lane actually doing what they are supposed to do - will slow down entry into the limiting point.
And well, legality of zipper approach is quite questionable.

It's my understanding that, if done correctly, the zipper merge should eliminate the existence of an "other lane".  That is, both lanes are equally responsible for merging and letting in.  That's what taking turns means.

What do you mean by "eliminating"? Would bulldozers move in and remove the pavement - or do you mean something else?

I meant something else.  To speak of "the other lane" indicates believing there is one lane that drivers should be in and another lane drivers should get out of.  A zipper merge should eliminate this mentality, encouraging both lanes to simply take turns at the taper.  In Australia, this would be defined as the difference between "merging" and "forming one lane".  (cf ACT road rules handbook (https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=11&cad=rja&uact=8&ved=0ahUKEwjTm7a_j_jWAhUK-J8KHQUkC1UQFghYMAo&url=https%3A%2F%2Fwww.accesscanberra.act.gov.au%2Fapp%2Fanswers%2Fdetail%2Fa_id%2F3531&usg=AOvVaw0HZlGsKnDMBKoLKUgZJfnc), page 38, on the difference between the two)

Quote from: kphoger on October 17, 2017, 01:05:25 PM

Quote from: kalvado on October 17, 2017, 12:01:04 PM

Quote from: kphoger on October 17, 2017, 10:47:53 AM

Quote from: kalvado on October 17, 2017, 10:30:50 AM

Quote from: kphoger on October 17, 2017, 10:24:44 AM
The throughput at the bottleneck remains the same either way, right?  All that's really changing with a zipper merge is that, between the two lanes, more storage is accomplished with the zipper merge.  Plus it also discourages the mentality that "this is my lane, dammit, so you can just sit there and wait because you didn't move over when I think you should have."

I've seen a lot of argument as to why a zipper merge might not actually be benificial, but where are the arguments that it's detrimental?

Actually zipper slightly  reduces throughput at the bottleneck. Having to do two things - lane change and accelerate, while making sure driver in the other lane actually doing what they are supposed to do - will slow down entry into the limiting point.
And well, legality of zipper approach is quite questionable.

It's my understanding that, if done correctly, the zipper merge should eliminate the existence of an "other lane".  That is, both lanes are equally responsible for merging and letting in.  That's what taking turns means.

What do you mean by "eliminating"? Would bulldozers move in and remove the pavement - or do you mean something else?

I meant something else.  To speak of "the other lane" indicates believing there is one lane that drivers should be in and another lane drivers should get out of.  A zipper merge should eliminate this mentality, encouraging both lanes to simply take turns at the taper.  In Australia, this would be defined as the difference between "merging" and "forming one lane".  (cf ACT road rules handbook (https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=11&cad=rja&uact=8&ved=0ahUKEwjTm7a_j_jWAhUK-J8KHQUkC1UQFghYMAo&url=https%3A%2F%2Fwww.accesscanberra.act.gov.au%2Fapp%2Fanswers%2Fdetail%2Fa_id%2F3531&usg=AOvVaw0HZlGsKnDMBKoLKUgZJfnc), page 38, on the difference between the two)

You may eliminate "my lane" mentality, but you cannot eliminate the fact that there are two (or more) vehicles with intention to proceed into the same spot at the same time. You may implement different rules and laws addressing the situation (one yields, both are equal, courtesy of giving more breathing space to a more needy vehicle - e.g. heavy 18-wheeler having hard time accelerating), but not the fact that there is this lane and that lane - and potential for the accident when this and that do not cooperate.

And legislation may be different between different areas. I may be wrong, but I didn't see any discrepancies in state rules saying that traffic on the main highway has right of way over traffic on ramp. Looks like Australia thinks differently.
But talking about US with "ramp traffic yields" laws -  as we talked upstream, situations where you handpick one set of rules over the other set in each specific situation is a recipe for an accident. We can say that ramp merge is clearly different from construction zone merge - but soon there will be examples of situations in between, causing all sort of problems.

Quote from: long string of quotes

Quote from: kalvado on October 17, 2017, 01:18:18 PM
situations where you handpick one set of rules over the other set in each specific situation is a recipe for an accident. We can say that ramp merge is clearly different from construction zone merge - but soon there will be examples of situations in between, causing all sort of problems.

But this is how things change.  Any new thing is experimented with in certain locations in specific situations, then other places like the idea and try it out.  Eventually, sloppily, and haphazardly, it–whatever it is–becomes mainstream and even finds its way into the MUTCD.  Hardly anything just gets dropped on every highway in the nation at once like a nuke.

Quote from: kphoger on October 17, 2017, 01:38:41 PM

Quote from: long string of quotes

Quote from: kalvado on October 17, 2017, 01:18:18 PM
situations where you handpick one set of rules over the other set in each specific situation is a recipe for an accident. We can say that ramp merge is clearly different from construction zone merge - but soon there will be examples of situations in between, causing all sort of problems.

But this is how things change.  Any new thing is experimented with in certain locations in specific situations, then other places like the idea and try it out.  Eventually, sloppily, and haphazardly, it–whatever it is–becomes mainstream and even finds its way into the MUTCD.  Hardly anything just gets dropped on every highway in the nation at once like a nuke.

Is it broken enough so that it needs a fix?
If there are routine delays more than 10 minutes (1 mile worth of a backup - right where "free lane space" arguments gains weight), then maybe you need something other than a lipstick and a bandaid?..
Given that the price of it is total overhaul of "right of way" concept... This is pretty much like replacing red and green on traffic light because. uhm... people respond faster to green and orange, for example - with orange meaning "go" , and blue - "stop".  It would save 10 miliseconds per vehicle, it must be worth it!

Quote from: kalvado on October 17, 2017, 01:49:19 PM

Quote from: kphoger on October 17, 2017, 01:38:41 PM

Quote from: long string of quotes

Quote from: kalvado on October 17, 2017, 01:18:18 PM
situations where you handpick one set of rules over the other set in each specific situation is a recipe for an accident. We can say that ramp merge is clearly different from construction zone merge - but soon there will be examples of situations in between, causing all sort of problems.

But this is how things change.  Any new thing is experimented with in certain locations in specific situations, then other places like the idea and try it out.  Eventually, sloppily, and haphazardly, it–whatever it is–becomes mainstream and even finds its way into the MUTCD.  Hardly anything just gets dropped on every highway in the nation at once like a nuke.

Is it broken enough so that it needs a fix?
If there are routine delays more than 10 minutes (1 mile worth of a backup - right where "free lane space" arguments gains weight), then maybe you need something other than a lipstick and a bandaid?..
Given that the price of it is total overhaul of "right of way" concept... This is pretty much like replacing red and green on traffic light because. uhm... people respond faster to green and orange, for example - with orange meaning "go" , and blue - "stop".  It would save 10 miliseconds per vehicle, it must be worth it!

Meanwhile, laws regarding turning right on red lights vary from state to state...

Quote from: kalvado on October 17, 2017, 10:30:50 AM

And well, legality of zipper approach is quite questionable.

[Citation Needed]

Quote from: GeekJedi on November 13, 2017, 07:33:23 PM

Quote from: kalvado on October 17, 2017, 10:30:50 AM

And well, legality of zipper approach is quite questionable.

[Citation Needed]

May I have your state, please?

Quote from: GeekJedi on November 13, 2017, 07:33:23 PM

Quote from: kalvado on October 17, 2017, 10:30:50 AM

And well, legality of zipper approach is quite questionable.

[Citation Needed]

It's been a few years, but I think there was one state that wrote the zipper merge into law for construction. Tennessee, perhaps?

Quote from: kalvado on November 13, 2017, 07:40:33 PM

Quote from: GeekJedi on November 13, 2017, 07:33:23 PM

Quote from: kalvado on October 17, 2017, 10:30:50 AM
And well, legality of zipper approach is quite questionable.

[Citation Needed]

May I have your state, please?

I think he's in Wisconsin.

Quote from: jakeroot on November 13, 2017, 11:20:33 PM

I think he's in Wisconsin.

Correct. From a recent news story:

"The Wisconsin State Patrol said there is no "bright line rule" as far as statutes go for merging. Law enforcement say cars already on the interstate have the right of way, meaning they do not have to move, but other than that, merging just comes down to common courtesy."

So it appears that, combined with the rule that construction signage trumps most everything else, removes any "question" on legality.

Quote from: GeekJedi on November 14, 2017, 07:50:04 AM

Quote from: jakeroot on November 13, 2017, 11:20:33 PM

I think he's in Wisconsin.

Correct. From a recent news story:

"The Wisconsin State Patrol said there is no "bright line rule" as far as statutes go for merging. Law enforcement say cars already on the interstate have the right of way, meaning they do not have to move, but other than that, merging just comes down to common courtesy."

So it appears that, combined with the rule that construction signage trumps most everything else, removes any "question" on legality.

Of course, construction zone sign is  a priority. If there is no sign..
346.13(1) " operator of a vehicle shall drive as nearly as practicable entirely within a single lane and shall not deviate from the traffic lane in which the operator is driving without first ascertaining that such movement can be made with safety to other vehicles approaching from the rear. " In practical terms, in case of accident due to lane change, vehicle changing lane would be seen as responsible for the accident.
So whoever need to get an insurance for their clunker may drive into your door as you do last-second zipper, and have a good chance of charging your insurance. Otherwise zipper is no problem.

Quote from: kalvado on November 14, 2017, 08:33:24 AM

Quote from: GeekJedi on November 14, 2017, 07:50:04 AM

Quote from: jakeroot on November 13, 2017, 11:20:33 PM

I think he's in Wisconsin.

Correct. From a recent news story:

"The Wisconsin State Patrol said there is no "bright line rule" as far as statutes go for merging. Law enforcement say cars already on the interstate have the right of way, meaning they do not have to move, but other than that, merging just comes down to common courtesy."

So it appears that, combined with the rule that construction signage trumps most everything else, removes any "question" on legality.

Of course, construction zone sign is  a priority. If there is no sign..
346.13(1) " operator of a vehicle shall drive as nearly as practicable entirely within a single lane and shall not deviate from the traffic lane in which the operator is driving without first ascertaining that such movement can be made with safety to other vehicles approaching from the rear. " In practical terms, in case of accident due to lane change, vehicle changing lane would be seen as responsible for the accident.
So whoever need to get an insurance for their clunker may drive into your door as you do last-second zipper, and have a good chance of charging your insurance. Otherwise zipper is no problem.

In that case, they would find any reason to have an accident - run a stop sign, hit a parked vehicle, etc, etc. 

Quote from: jeffandnicole on November 14, 2017, 09:08:14 AM

Quote from: kalvado on November 14, 2017, 08:33:24 AM

Quote from: GeekJedi on November 14, 2017, 07:50:04 AM

Quote from: jakeroot on November 13, 2017, 11:20:33 PM

I think he's in Wisconsin.

Correct. From a recent news story:

"The Wisconsin State Patrol said there is no "bright line rule" as far as statutes go for merging. Law enforcement say cars already on the interstate have the right of way, meaning they do not have to move, but other than that, merging just comes down to common courtesy."

So it appears that, combined with the rule that construction signage trumps most everything else, removes any "question" on legality.

Of course, construction zone sign is  a priority. If there is no sign..
346.13(1) " operator of a vehicle shall drive as nearly as practicable entirely within a single lane and shall not deviate from the traffic lane in which the operator is driving without first ascertaining that such movement can be made with safety to other vehicles approaching from the rear. " In practical terms, in case of accident due to lane change, vehicle changing lane would be seen as responsible for the accident.
So whoever need to get an insurance for their clunker may drive into your door as you do last-second zipper, and have a good chance of charging your insurance. Otherwise zipper is no problem.

In that case, they would find any reason to have an accident - run a stop sign, hit a parked vehicle, etc, etc.

Nope, that would be THEIR fault - and that would reflect on insurance premium. Here we're talking about not at fault situation. Like someone running stop sign on you..

Quote from: kalvado on November 14, 2017, 08:33:24 AM

Quote from: GeekJedi on November 14, 2017, 07:50:04 AM

Quote from: jakeroot on November 13, 2017, 11:20:33 PM

I think he's in Wisconsin.

Correct. From a recent news story:

"The Wisconsin State Patrol said there is no "bright line rule" as far as statutes go for merging. Law enforcement say cars already on the interstate have the right of way, meaning they do not have to move, but other than that, merging just comes down to common courtesy."

So it appears that, combined with the rule that construction signage trumps most everything else, removes any "question" on legality.

Of course, construction zone sign is  a priority. If there is no sign..
346.13(1) " operator of a vehicle shall drive as nearly as practicable entirely within a single lane and shall not deviate from the traffic lane in which the operator is driving without first ascertaining that such movement can be made with safety to other vehicles approaching from the rear. " In practical terms, in case of accident due to lane change, vehicle changing lane would be seen as responsible for the accident.
So whoever need to get an insurance for their clunker may drive into your door as you do last-second zipper, and have a good chance of charging your insurance. Otherwise zipper is no problem.

How does that contradict a zipper merge, though?  Telling traffic to form one lane at the merge point, a half-mile upstream of the merge point, or at various points along the continuum doesn't change one's responsibility to make sure nobody's next to him before changing lanes.

Quote from: kphoger on November 14, 2017, 12:58:29 PM

Quote from: kalvado on November 14, 2017, 08:33:24 AM

Quote from: GeekJedi on November 14, 2017, 07:50:04 AM

Quote from: jakeroot on November 13, 2017, 11:20:33 PM

I think he's in Wisconsin.

Correct. From a recent news story:

"The Wisconsin State Patrol said there is no "bright line rule" as far as statutes go for merging. Law enforcement say cars already on the interstate have the right of way, meaning they do not have to move, but other than that, merging just comes down to common courtesy."

So it appears that, combined with the rule that construction signage trumps most everything else, removes any "question" on legality.

Of course, construction zone sign is  a priority. If there is no sign..
346.13(1) " operator of a vehicle shall drive as nearly as practicable entirely within a single lane and shall not deviate from the traffic lane in which the operator is driving without first ascertaining that such movement can be made with safety to other vehicles approaching from the rear. " In practical terms, in case of accident due to lane change, vehicle changing lane would be seen as responsible for the accident.
So whoever need to get an insurance for their clunker may drive into your door as you do last-second zipper, and have a good chance of charging your insurance. Otherwise zipper is no problem.

How does that contradict a zipper merge, though?  Telling traffic to form one lane at the merge point, a half-mile upstream of the merge point, or at various points along the continuum doesn't change one's responsibility to make sure nobody's next to him before changing lanes.

Forming single lane requires cars in one lane to stay in lane, and cars in the other lane - change lanes - so lanes are not equal. Strictly speaking, there is no legal requirement for cars already in continuing lane to let merging cars in. And if you try to merge without their cooperation, you may end up being fully responsible for accident. As mentioned above, such cooperation is a common courtesy, not legal requirement.
Forming single lane way upstream usually means doing so when there are still gaps in still moving traffic.

Quote from: kalvado on November 14, 2017, 01:09:25 PM

Quote from: kphoger on November 14, 2017, 12:58:29 PM

Quote from: kalvado on November 14, 2017, 08:33:24 AM

Quote from: GeekJedi on November 14, 2017, 07:50:04 AM

Quote from: jakeroot on November 13, 2017, 11:20:33 PM

I think he's in Wisconsin.

Correct. From a recent news story:

"The Wisconsin State Patrol said there is no "bright line rule" as far as statutes go for merging. Law enforcement say cars already on the interstate have the right of way, meaning they do not have to move, but other than that, merging just comes down to common courtesy."

So it appears that, combined with the rule that construction signage trumps most everything else, removes any "question" on legality.

Of course, construction zone sign is  a priority. If there is no sign..
346.13(1) " operator of a vehicle shall drive as nearly as practicable entirely within a single lane and shall not deviate from the traffic lane in which the operator is driving without first ascertaining that such movement can be made with safety to other vehicles approaching from the rear. " In practical terms, in case of accident due to lane change, vehicle changing lane would be seen as responsible for the accident.
So whoever need to get an insurance for their clunker may drive into your door as you do last-second zipper, and have a good chance of charging your insurance. Otherwise zipper is no problem.

How does that contradict a zipper merge, though?  Telling traffic to form one lane at the merge point, a half-mile upstream of the merge point, or at various points along the continuum doesn't change one's responsibility to make sure nobody's next to him before changing lanes.

Forming single lane requires cars in one lane to stay in lane, and cars in the other lane - change lanes - so lanes are not equal. Strictly speaking, there is no legal requirement for cars already in continuing lane to let merging cars in. And if you try to merge without their cooperation, you may end up being fully responsible for accident. As mentioned above, such cooperation is a common courtesy, not legal requirement.
Forming single lane way upstream usually means doing so when there are still gaps in still moving traffic.

So what do you think of Oklahoma's [ STATE LAW | MERGE NOW ----> ] signs that are posted a ways upstream of the lane closure?  I find that to be no different, legally speaking, than a zipper merge sign.

Quote from: kalvado on November 14, 2017, 01:09:25 PM

Quote from: kphoger on November 14, 2017, 12:58:29 PM

Quote from: kalvado on November 14, 2017, 08:33:24 AM

Quote from: GeekJedi on November 14, 2017, 07:50:04 AM

Quote from: jakeroot on November 13, 2017, 11:20:33 PM

I think he's in Wisconsin.

Correct. From a recent news story:

"The Wisconsin State Patrol said there is no "bright line rule" as far as statutes go for merging. Law enforcement say cars already on the interstate have the right of way, meaning they do not have to move, but other than that, merging just comes down to common courtesy."

So it appears that, combined with the rule that construction signage trumps most everything else, removes any "question" on legality.

Of course, construction zone sign is  a priority. If there is no sign..
346.13(1) " operator of a vehicle shall drive as nearly as practicable entirely within a single lane and shall not deviate from the traffic lane in which the operator is driving without first ascertaining that such movement can be made with safety to other vehicles approaching from the rear. " In practical terms, in case of accident due to lane change, vehicle changing lane would be seen as responsible for the accident.
So whoever need to get an insurance for their clunker may drive into your door as you do last-second zipper, and have a good chance of charging your insurance. Otherwise zipper is no problem.

How does that contradict a zipper merge, though?  Telling traffic to form one lane at the merge point, a half-mile upstream of the merge point, or at various points along the continuum doesn't change one's responsibility to make sure nobody's next to him before changing lanes.

Forming single lane requires cars in one lane to stay in lane, and cars in the other lane - change lanes - so lanes are not equal. Strictly speaking, there is no legal requirement for cars already in continuing lane to let merging cars in. And if you try to merge without their cooperation, you may end up being fully responsible for accident. As mentioned above, such cooperation is a common courtesy, not legal requirement.
Forming single lane way upstream usually means doing so when there are still gaps in still moving traffic.

You can bend semantics all you want, but it's pretty clear. A "zipper merge" sign in a construction area is a "controlling" sign (the signs are clearly labeled "Take Turns" and "Merge Here"). Don't follow it? You're responsible...aside from the fact that in any of your "what about" scenarios, the person hitting your car would be at fault - likely for inattentive driving, regardless of who's turn it was.

Quote from: kalvado on November 14, 2017, 01:09:25 PM

Quote from: kphoger on November 14, 2017, 12:58:29 PM

Quote from: kalvado on November 14, 2017, 08:33:24 AM

Quote from: GeekJedi on November 14, 2017, 07:50:04 AM

Quote from: jakeroot on November 13, 2017, 11:20:33 PM
I think he's in Wisconsin.

Correct. From a recent news story:

"The Wisconsin State Patrol said there is no "bright line rule" as far as statutes go for merging. Law enforcement say cars already on the interstate have the right of way, meaning they do not have to move, but other than that, merging just comes down to common courtesy."

So it appears that, combined with the rule that construction signage trumps most everything else, removes any "question" on legality.

Of course, construction zone sign is  a priority. If there is no sign..
346.13(1) " operator of a vehicle shall drive as nearly as practicable entirely within a single lane and shall not deviate from the traffic lane in which the operator is driving without first ascertaining that such movement can be made with safety to other vehicles approaching from the rear. " In practical terms, in case of accident due to lane change, vehicle changing lane would be seen as responsible for the accident.
So whoever need to get an insurance for their clunker may drive into your door as you do last-second zipper, and have a good chance of charging your insurance. Otherwise zipper is no problem.

How does that contradict a zipper merge, though?  Telling traffic to form one lane at the merge point, a half-mile upstream of the merge point, or at various points along the continuum doesn't change one's responsibility to make sure nobody's next to him before changing lanes.

Forming single lane requires cars in one lane to stay in lane, and cars in the other lane - change lanes - so lanes are not equal. Strictly speaking, there is no legal requirement for cars already in continuing lane to let merging cars in. And if you try to merge without their cooperation, you may end up being fully responsible for accident. As mentioned above, such cooperation is a common courtesy, not legal requirement.
Forming single lane way upstream usually means doing so when there are still gaps in still moving traffic.

Zipper merging is not cramming your way in at the last second (at least not in principal). It's when the drivers in the lane that doesn't end, widen their following distance to allow drivers, in the lane that does end, to legally merge in front of them. Do they have any legal requirement to do so? Of course not (barring any sign that specifically tells drivers to zipper merge). But, drivers create the gaps so that the merge is a legal maneuver.

Quote from: jakeroot on November 14, 2017, 03:05:01 PM
Zipper merging is not cramming your way in at the last second (at least not in principal). It's when the drivers in the lane that doesn't end, widen their following distance to allow drivers, in the lane that does end, to legally merge in front of them. Do they have any legal requirement to do so? Of course not (barring any sign that specifically tells drivers to zipper merge). But, drivers create the gaps so that the merge is a legal maneuver.

SO it COULD be a legal maneuver - but it is equally legal NOT to cooperate. And this is same as yielding to the traffic which has no right of way. Not uncommon, but sometimes dangerous. I often wave drivers through on the crosswalk (if they can make it fast - as all it takes me is crossing on further side of crosswalk 2 second later, 100% safe, 0 delay for me, 10 seconds win for driver), but I get really pissed off when traffic on roundabout yields to entering traffic - even if they yield to me.
Not sure where zipper fits in here - often those staying in the lane past argeed yield point are really aggressive squeezing in

Quote from: kalvado on November 14, 2017, 04:20:05 PM
it is equally legal NOT to cooperate.

I'm fairly certain that disobeying a construction zone regulatory sign (take turns at merge) is in fact not legal.

Quote from: kphoger on November 14, 2017, 04:23:46 PM

Quote from: kalvado on November 14, 2017, 04:20:05 PM
it is equally legal NOT to cooperate.

I'm fairly certain that disobeying a construction zone regulatory sign (take turns at merge) is in fact not legal.

I still have to see such a sign myself. But if there is a sign - sure you're right. Is it a legal sign included into MUTCD, BTW?
But in case there is no sign, see above.

Quote from: kalvado on November 14, 2017, 04:26:45 PM

Quote from: kphoger on November 14, 2017, 04:23:46 PM

Quote from: kalvado on November 14, 2017, 04:20:05 PM
it is equally legal NOT to cooperate.

I'm fairly certain that disobeying a construction zone regulatory sign (take turns at merge) is in fact not legal.

I still have to see such a sign myself.

This is how Minnesota does it.

(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fwww.thegazette.com%2Fstoryimage%2FGA%2F20160524%2FARTICLE%2F160529596%2FAR%2F0%2FAR-160529596.jpg%26amp%3BMaxH%3D500%26amp%3BMaxW%3D652&hash=7039ae0d0b42c29346a123f2bd2c942be87b5d74)

Quote from: kphoger on November 14, 2017, 04:30:04 PM

Quote from: kalvado on November 14, 2017, 04:26:45 PM

Quote from: kphoger on November 14, 2017, 04:23:46 PM

Quote from: kalvado on November 14, 2017, 04:20:05 PM
it is equally legal NOT to cooperate.

I'm fairly certain that disobeying a construction zone regulatory sign (take turns at merge) is in fact not legal.

I still have to see such a sign myself.

This is how Minnesota does it.

(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fwww.thegazette.com%2Fstoryimage%2FGA%2F20160524%2FARTICLE%2F160529596%2FAR%2F0%2FAR-160529596.jpg%26amp%3BMaxH%3D500%26amp%3BMaxW%3D652&hash=7039ae0d0b42c29346a123f2bd2c942be87b5d74)

Then there's this, seen on page 4 of this thread:

Quote from: 1995hoo on October 16, 2017, 08:35:51 AM
Yesterday we encountered this sign on I-70 passing Terre Haute, Indiana. Wasn't a true zipper merge because the left lane ultimately ended more than a mile further down the road, but the sign is clear enough, right? Not to the people on I-70. Almost everyone panicked and moved over a mile in advance of the merge point. On the plus side for us, that meant we sailed past a long line of cars because I merge at the end just like the sign said (only one guy from Oklahoma seemed to take umbrage, but that was right at the end anyway).

(https://uploads.tapatalk-cdn.com/20171016/b28d4d998e486ed43b288c0ee080b5ba.jpg)

If one wants to quibble, the "Take Turns At Merge" verbiage is in temporary work zone warning colors, not regulatory colors.

Quote from: hbelkins on November 15, 2017, 11:42:03 AM
If one wants to quibble, the "Take Turns At Merge" verbiage is in temporary work zone warning colors, not regulatory colors.

I find it hard to imagine anyone being ticketed for disobeying these sorts of signs regardless of what color is used!

Unless I'm crazy, the use of orange in a construction zone supersedes any MUTCD rules regarding sign color. Every sign seems to be orange, even guide signs (at least in some areas). Obviously, warning and guide signs don't have the same legal pickle that regulatory signage has. But my understanding has been that, even if the sign is orange, you are still required to follow the rules of the sign.

On my way home from work today, I encountered an example of how it can be detrimental to merge early.

I was getting on the Interstate, and traffic was all backed up.  There were multiple orange signs saying "RIGHT LANE CLOSED", and so everyone in the right lane was scooting over into the left lane at the first opportunity.  This was bogging down the left lane, and some folks were coming to a dead stop in the right lane in order to wait for a gap in the left lane.  I proceeded along in the right lane.  And guess what?  The right lane was NOT closed.  Either the road work was finished or hadn't started yet, but both lanes were wide open.  All that bottleneck for nothing.  If everyone had simply waited until their lane was actually ending, then none of that delay would have happened.

I never trust a "LANE CLOSED" sign.  Unless I can see with my own eyes that there are cones blocking my lane, then I assume the sign is posted in error.  It turns out to be true quite often.

I've ran into similar issues in rural Virginia before, where people seem super lane change-happy whenever there's even a hint of a lane ending. Paid off last time I was out near Charlottesville. Sign said lane closed ahead...I stayed the course, all by myself. Lane never closed. Suddenly a bunch of cars filled in behind me...phanton congestion if I've ever seen it.

NCDOT used this sign (https://uploads.tapatalk-cdn.com/20190102/86c8aad30c1e9e571d974574762db6c6.jpg)


iPhone

^ So I am supposed to watch for a giant zipper? :spin:

Quote from: Amtrakprod on January 01, 2019, 09:13:49 PM
NCDOT used this sign (https://uploads.tapatalk-cdn.com/20190102/86c8aad30c1e9e571d974574762db6c6.jpg)


iPhone

Two rail lines crash together in a tunnel ahead?

I think the sign makes sense, though I'd like a supplementary "TAKE TURNS MERGING" tab below it.

Quote from: jakeroot on January 06, 2019, 07:32:45 PM
I think the sign makes sense, though I'd like a supplementary "TAKE TURNS MERGING" tab below it.

Agree.  I'd guess the general motoring public will not make sense of that sign.  I can't recall ever hearing zipper merging being referred to as such in common verbiage.

NYSDOT just uses an advance "single lane" sign and a modified symmetrical W4-2 sign with no dotted line. It seems to get the idea across fine, notwithstanding the one car out of every 20 or so who'll cut the line for no reason other than feeling more entitled to it.

Quote from: signalman on January 06, 2019, 08:00:30 PM

Quote from: jakeroot on January 06, 2019, 07:32:45 PM
I think the sign makes sense, though I'd like a supplementary "TAKE TURNS MERGING" tab below it.

Agree.  I'd guess the general motoring public will not make sense of that sign.  I can't recall ever hearing zipper merging being referred to as such in common verbiage.

I guess it depends on your location. WSDOT uses the "zipper" terminology in their PR (not on actual signs) often enough for it to have entered the public lexicon in Seattle. But areas less prone to congestion may not use or have heard of the term.

Quote from: DaBigE on January 06, 2019, 03:19:07 PM

Quote from: Amtrakprod on January 01, 2019, 09:13:49 PM
NCDOT used this sign (https://uploads.tapatalk-cdn.com/20190102/86c8aad30c1e9e571d974574762db6c6.jpg)


iPhone

Two rail lines crash together in a tunnel ahead?

If right after a Rest Area:  Did You Zip Up?? (albeit the sign in the photo would then be considered upside-down).

Quote from: jakeroot on January 06, 2019, 07:32:45 PM
I think the sign makes sense, though I'd like a supplementary "TAKE TURNS MERGING" tab below it.

MnDOT even has such a sign (though phrased as "TAKE TURNS AT MERGE.")

(https://i.imgur.com/6peWAIP.jpg)

Edit to add: A similar sign was also posted at the merge point.

(https://i.imgur.com/1n8k3OT.jpg)

(I'm also now regretting getting more pictures of other similar signs in other I-35 work zones. There's been a lot of them the last couple years, so hopefully they should be mostly done with for a while. :-D)

Quote from: jakeroot on January 06, 2019, 09:21:25 PM

Quote from: signalman on January 06, 2019, 08:00:30 PM

Quote from: jakeroot on January 06, 2019, 07:32:45 PM
I think the sign makes sense, though I'd like a supplementary "TAKE TURNS MERGING" tab below it.

Agree.  I'd guess the general motoring public will not make sense of that sign.  I can't recall ever hearing zipper merging being referred to as such in common verbiage.

I guess it depends on your location. WSDOT uses the "zipper" terminology in their PR (not on actual signs) often enough for it to have entered the public lexicon in Seattle. But areas less prone to congestion may not use or have heard of the term.

I have my doubts that, even in an area where the term "zipper merge" is used extensively in PR, it would be readily understood by the majority of drivers.  In other words, take 1000 drivers and ask them what a zipper merge is, and I'd bet at least half of them wouldn't know.  But even if they do, it's still a crappy warning sign because it's just a picture of a zipper.  It doesn't say anything about a merge (just a zipper, and it's quite the cognitive leap to go from "watch out for the huge zipper" to "lanes merging ahead"), plus it doesn't actually tell you what to do (it's just telling you to watch out).

tl;dr - It's cute but worthless.

Quote from: MNHighwayMan on January 06, 2019, 09:43:55 PM
(I'm also now regretting getting more pictures of other similar signs in other I-35 work zones. There's been a lot of them the last couple years, so hopefully they should be mostly done with for a while. :-D)

I'm sure you've been sitting in 5-mph traffic during those construction projects enough times to have snapped some pictures, too!  I swear, Owatonna was a four-letter word for a while.

Quote from: kphoger on January 07, 2019, 09:14:53 PM

Quote from: jakeroot on January 06, 2019, 09:21:25 PM

Quote from: signalman on January 06, 2019, 08:00:30 PM

Quote from: jakeroot on January 06, 2019, 07:32:45 PM
I think the sign makes sense, though I'd like a supplementary "TAKE TURNS MERGING" tab below it.

Agree.  I'd guess the general motoring public will not make sense of that sign.  I can't recall ever hearing zipper merging being referred to as such in common verbiage.

I guess it depends on your location. WSDOT uses the "zipper" terminology in their PR (not on actual signs) often enough for it to have entered the public lexicon in Seattle. But areas less prone to congestion may not use or have heard of the term.

I have my doubts that, even in an area where the term "zipper merge" is used extensively in PR, it would be readily understood by the majority of drivers.  In other words, take 1000 drivers and ask them what a zipper merge is, and I'd bet at least half of them wouldn't know.  But even if they do, it's still a crappy warning sign because it's just a picture of a zipper.  It doesn't say anything about a merge (just a zipper, and it's quite the cognitive leap to go from "watch out for the huge zipper" to "lanes merging ahead"), plus it doesn't actually tell you what to do (it's just telling you to watch out).

tl;dr - It's cute but worthless.

I guess it depends on whether or not the person experiences a merge on their commute. If they do, they're probably familiar with the concept. If not, I doubt they've bothered to listen to any PR to begin with.

Regardless, I'd hate to see any new warning signs added to the MUTCD without symbols. As implemented, I wouldn't say NC's sign is worthless (I'm sure drivers familiar with the "zipper" got the connection), but (as I suggested before) a supplemental tab would massively improve recognition of the expected behavior.

I saw something like this on another website, and I think it gets the point across. I've recreated the sign and added the text.

(https://i.imgur.com/55IYd5s.png)

Quote from: kphoger on January 07, 2019, 09:16:36 PM

Quote from: MNHighwayMan on January 06, 2019, 09:43:55 PM
(I'm also now regretting getting more pictures of other similar signs in other I-35 work zones. There's been a lot of them the last couple years, so hopefully they should be mostly done with for a while. :-D)

I'm sure you've been sitting in 5-mph traffic during those construction projects enough times to have snapped some pictures, too!  I swear, Owatonna was a four-letter word for a while.

That Owatonna closure was definitely fun, for sure. Unfortunately it took me this thread to realize that Minnesota's signage is certainly not the norm, and actually probably pretty far above other states in terms of quality. Where else would they use flashing beacons ten miles in advance of a lane closure to warn of potential backups? :hmmm:

Quote from: jakeroot on January 07, 2019, 11:43:58 PM
I saw something like this on another website, and I think it gets the point across. I've recreated the sign and added the text.

(https://i.imgur.com/55IYd5s.png)

I like this a whole lot better. IMO, the tab at the top could easily be omitted, as it just sucks up reading/comprehension time.

Quote from: jakeroot on January 07, 2019, 11:43:58 PM
I guess it depends on whether or not the person experiences a merge on their commute. If they do, they're probably familiar with the concept. If not, I doubt they've bothered to listen to any PR to begin with.

Yep.  I see this on a fairly regular basis over here.  On our NJ Route 55, which is both a commuter highway and shore route, on weekdays you see people staying in both lanes up to the very end.  On weekends, when you get the Pennsy driver coming back from their vacation who probably doesn't commute very often, they merge over very early, and in some situations feel they should ride the center line because they feel that the merging should've happened when they did it. 

The weekday commuting merging goes much more smoothly than the weekend tourist merging.

Quote from: DaBigE on January 08, 2019, 01:37:22 PM

Quote from: jakeroot on January 07, 2019, 11:43:58 PM
I saw something like this on another website, and I think it gets the point across. I've recreated the sign and added the text.

(https://i.imgur.com/55IYd5s.png)

I like this a whole lot better. IMO, the tab at the top could easily be omitted, as it just sucks up reading/comprehension time.

Agreed.  The sign with bottom plaque is all that's needed.  "Zipper" is just a cute PR name that drivers don't actually need to know.

Quote from: kphoger on January 07, 2019, 09:14:53 PM
I have my doubts that, even in an area where the term "zipper merge" is used extensively in PR, it would be readily understood by the majority of drivers.  In other words, take 1000 drivers and ask them what a zipper merge is, and I'd bet at least half of them wouldn't know.  But even if they do, it's still a crappy warning sign because it's just a picture of a zipper.  It doesn't say anything about a merge (just a zipper, and it's quite the cognitive leap to go from "watch out for the huge zipper" to "lanes merging ahead"), plus it doesn't actually tell you what to do (it's just telling you to watch out).

I think that's a fair doubt. After all, how many people still don't know how a roundabout works, despite extensive PR from a number of different state DOTs for like 25 years now? :-D

That said, I'm guessing the zipper sign isn't a standalone install, but part of a broader signage scheme; there are probably other signs nearby that contextualize what it means.

Quote from: jeffandnicole on January 08, 2019, 01:41:51 PM
On our NJ Route 55, which is both a commuter highway and shore route, on weekdays you see people staying in both lanes up to the very end.  On weekends, when you get the Pennsy driver coming back from their vacation who probably doesn't commute very often, they merge over very early, and in some situations feel they should ride the center line because they feel that the merging should've happened when they did it.

Which is interesting (and to the same point as my first quote), since Pennsy is one state that routinely instructs drivers to zipper-merge. ("Use both lanes to merge point" is their verbiage.)

You don't have to know anything about roundabouts to follow the yield signs. Those are long established and in use nationwide for various reasons. The zipper signs are non-standard, and has no nationwide standard.

Quote from: jeffandnicole on January 08, 2019, 01:41:51 PM
.... they merge over very early, and in some situations feel they should ride the center line because they feel that the merging should've happened when they did it. 

....

I see that sort of thing pretty much anywhere a merge occurs, and it doesn't matter whether it's commuters or long-distance traffic. Saw it in Indiana despite a sign saying to go to the end and take turns–instead, most people panicked and rushed to form a single line a mile or two in advance. (Of course we have one person in this thread who thinks that's how it's supposed to be.) I still cannot fathom how some people cannot understand that it makes no sense whatsoever if every different driver designates his own merge point and says nobody else can merge after that spot.

It's really maddening when one of the lanes is configured so that it can either merge or exit yet people try to block anyone using it. The ramp from the Ninth Street Tunnel to southbound I-395 in DC was like that for years–one lane exits to the right from the tunnel, and another lane to the right of that one comes down from D Street SW to join the ramp. For years, it was striped as two lanes, and partway down the ramp the right lane allowed you either to exit to the right to Maine Avenue or to go straight and merge with the left lane into a single lane onto I-395. Despite the clear two-lane configuration with what should have been a zipper merge at the end, some people were convinced anyone who was coming from D Street and who didn't stop right at the beginning to get over was somehow "cutting," and the people who felt that way would try to straddle both lanes, even though the right lane gave the option of exiting to the right onto Maine Avenue (I often exit that way, and there's no reason why I should be stuck behind the "merge-early-block-everyone-else" crowd when I'm exiting that way). The ramp is no longer striped as two lanes, so now it's a bit of a crapshoot from one day to the next how the traffic will form up (long-time ramp users who are polite try to form two lanes to allow people headed to Maine Avenue to get past).

Quote from: 1995hoo on January 08, 2019, 04:12:07 PM
(Of course we have one person in this thread who thinks that's how it's supposed to be.)

Actually I got a thought regarding all this...
Is there any correlation between zipper approach altitude and home area?
Apparently, queue length and possibility of blocking previous exits is the only valid reason to enforce zipper. For such concern to be valid, the length of routine backup has to be comparable with distance between exits - e.g. heavy traffic and dense exits. Which mostly means megapolis environment.
As far as I understand, you live in a core DC area, which certainly qualifies you for "megapolis"... @jeffandnicole is another megapolis datapoint.
On the other hand, I can think of at least to people who are from lighter traffic area and have pretty sceptic oppinion about zipper. So is that a correlation?

Quote from: bzakharin on January 08, 2019, 03:12:32 PM
You don't have to know anything about roundabouts to follow the yield signs. Those are long established and in use nationwide for various reasons. The zipper signs are non-standard, and has no nationwide standard.

Exactly. So if people still don't understand roundabouts, despite them being very standard by now, it's very fair to doubt that they'll understand the zipper sign, despite any aggressive PR that may be accompanying them.

Quote from: jakeroot on January 07, 2019, 11:43:58 PM

Quote from: kphoger on January 07, 2019, 09:14:53 PM

Quote from: jakeroot on January 06, 2019, 09:21:25 PM

Quote from: signalman on January 06, 2019, 08:00:30 PM

Quote from: jakeroot on January 06, 2019, 07:32:45 PM
I think the sign makes sense, though I'd like a supplementary "TAKE TURNS MERGING" tab below it.

Agree.  I'd guess the general motoring public will not make sense of that sign.  I can't recall ever hearing zipper merging being referred to as such in common verbiage.

I guess it depends on your location. WSDOT uses the "zipper" terminology in their PR (not on actual signs) often enough for it to have entered the public lexicon in Seattle. But areas less prone to congestion may not use or have heard of the term.

I have my doubts that, even in an area where the term "zipper merge" is used extensively in PR, it would be readily understood by the majority of drivers.  In other words, take 1000 drivers and ask them what a zipper merge is, and I'd bet at least half of them wouldn't know.  But even if they do, it's still a crappy warning sign because it's just a picture of a zipper.  It doesn't say anything about a merge (just a zipper, and it's quite the cognitive leap to go from "watch out for the huge zipper" to "lanes merging ahead"), plus it doesn't actually tell you what to do (it's just telling you to watch out).

tl;dr - It's cute but worthless.

I guess it depends on whether or not the person experiences a merge on their commute. If they do, they're probably familiar with the concept. If not, I doubt they've bothered to listen to any PR to begin with.

Regardless, I'd hate to see any new warning signs added to the MUTCD without symbols. As implemented, I wouldn't say NC's sign is worthless (I'm sure drivers familiar with the "zipper" got the connection), but (as I suggested before) a supplemental tab would massively improve recognition of the expected behavior.

I saw something like this on another website, and I think it gets the point across. I've recreated the sign and added the text.

(https://i.imgur.com/55IYd5s.png)

PANYNJ uses a nearly identical sign (https://goo.gl/maps/Sx4Xs1QLHqG2). In downstate NY alternate merging is pretty socially engrained  so people tend to do it in appropriate situations whether or not there's signage.

Quote from: kphoger on January 08, 2019, 02:44:12 PM

Quote from: DaBigE on January 08, 2019, 01:37:22 PM

Quote from: jakeroot on January 07, 2019, 11:43:58 PM
I saw something like this on another website, and I think it gets the point across. I've recreated the sign and added the text.

(https://i.imgur.com/55IYd5s.png)

I like this a whole lot better. IMO, the tab at the top could easily be omitted, as it just sucks up reading/comprehension time.

Agreed.  The sign with bottom plaque is all that's needed.  "Zipper" is just a cute PR name that drivers don't actually need to know.

Ideally, I'd rather not have any additional text. The text on the bottom is arguably much more important.

I included the term "zipper merge" on top since that would be the text equivalent. "Take turns merging" is more of a regulatory message, whereas "zipper merge" is a warning of the situation, alongside established terms like "right lane ends". I'm not sure what other term might be better, but "zipper merge" is (as I said before) decently well-established in some places.

Quote from: jakeroot on January 09, 2019, 05:40:45 PM

Quote from: kphoger on January 08, 2019, 02:44:12 PM

Quote from: DaBigE on January 08, 2019, 01:37:22 PM

Quote from: jakeroot on January 07, 2019, 11:43:58 PM
I saw something like this on another website, and I think it gets the point across. I've recreated the sign and added the text.

(https://i.imgur.com/55IYd5s.png)

I like this a whole lot better. IMO, the tab at the top could easily be omitted, as it just sucks up reading/comprehension time.

Agreed.  The sign with bottom plaque is all that's needed.  "Zipper" is just a cute PR name that drivers don't actually need to know.

Ideally, I'd rather not have any additional text. The text on the bottom is arguably much more important.

I included the term "zipper merge" on top since that would be the text equivalent. "Take turns merging" is more of a regulatory message, whereas "zipper merge" is a warning of the situation, alongside established terms like "right lane ends". I'm not sure what other term might be better, but "zipper merge" is (as I said before) decently well-established in some places.

Given your explanation, the "Zipper Merge" plaque, if used, should go below the symbolic sign, as it's a supplementary plaque (similar to plaques used for the Circular Intersection sign or Divided Highway Begins/Ends). Placing it on top detracts from the more important information. The only plaques that should go on top of installations like this would be ones like New or Notice, as they're meant to draw attention/enhance conspicuity of the main sign.

I have a similar grip with municipalities that insist on installing a Roundabout plaque above a regulatory lane designation sign (https://goo.gl/maps/CKX4pGjEmnp). What makes my example even worse, is how small the text is in relation to its location relative to the approach and how many bits of information there are for the driver to have to process. My example has something else radically wrong with it...kudos to whomever finds what I am referring to.

^^

There appears to be a stop sign on that signpost to the right, directed at the short sidewalk piece that meets the road. What's that for?

Quote from: DaBigE on January 09, 2019, 06:50:23 PM

I have a similar grip with municipalities that insist on installing a Roundabout plaque above a regulatory lane designation sign (https://goo.gl/maps/CKX4pGjEmnp). What makes my example even worse, is how small the text is in relation to its location relative to the approach and how many bits of information there are for the driver to have to process. My example has something else radically wrong with it...kudos to whomever finds what I am referring to.

"Get in lane" instead of "Stay in lane"

Quote from: jakeroot on January 07, 2019, 11:43:58 PM
(https://i.imgur.com/55IYd5s.png)

Take turns merging?  In Chicago, surely you jest?

/Fuck the merge, I'm using the shoulder and then bull my way back in later.

Quote from: DaBigE on January 09, 2019, 06:50:23 PM
Given your explanation, the "Zipper Merge" plaque, if used, should go below the symbolic sign, as it's a supplementary plaque (similar to plaques used for the Circular Intersection sign or Divided Highway Begins/Ends). Placing it on top detracts from the more important information. The only plaques that should go on top of installations like this would be ones like New or Notice, as they're meant to draw attention/enhance conspicuity of the main sign.

That's a very good point. I wasn't sure I wanted two plaques on the bottom, so I split it up.

I have seen yellow plaques on top of signs for things that weren't new: http://bit.ly/2H52dJf (though these, in Arlington County, VA, were totally blank).

Quote from: Brandon on January 10, 2019, 08:53:40 AM
Take turns merging?  In Chicago, surely you jest?

/Fuck the merge, I'm using the shoulder and then bull my way back in later.

Better than merging early!

Quote from: 1995hoo on January 09, 2019, 10:09:58 PM
^^

There appears to be a stop sign on that signpost to the right, directed at the short sidewalk piece that meets the road. What's that for?

Winner, winner! (sorry, no chicken dinner) The short sidewalk is a ramp from the on-street bike lane to the off-road mixed-use path. These are wider than the typical 4-ft ones WisDOT includes with their urban roundabouts. However, if a cyclist follows the direction the trail Stop sign is aimed, they'll be heading the wrong way down the street. Even the ones posted which do face the proper direction (https://goo.gl/maps/Rip8HdG1hPE2) make little sense, as there's no one* to stop for. Not to deviate too far off-topic, but this city likes posting useless signs (https://goo.gl/maps/BcbM8F1sHnF2).

*Ok, sure there may be the occasional cyclist that will ride through the roundabout in a regular vehicle lane then go back to the bike lane, or car parking, but how often will those conflicts really occur?

Quote from: Amtrakprod on January 01, 2019, 09:13:49 PM
NCDOT used this sign (https://uploads.tapatalk-cdn.com/20190102/86c8aad30c1e9e571d974574762db6c6.jpg)


iPhone

XYZ

https://www.wbur.org/news/2019/08/19/driving-traffic-lane-closure-construction-maneuver-safety

Quote from: kphoger on January 07, 2019, 09:16:36 PM

Quote from: MNHighwayMan on January 06, 2019, 09:43:55 PM
(I'm also now regretting getting more pictures of other similar signs in other I-35 work zones. There's been a lot of them the last couple years, so hopefully they should be mostly done with for a while. :-D)

I'm sure you've been sitting in 5-mph traffic during those construction projects enough times to have snapped some pictures, too!  I swear, Owatonna was a four-letter word for a while.

Seriously. Last summer, we left Des Moines 20 minutes after my grandparents. We decided to pop off I-35 right where traffic came to a halt, at Exit 32 (Hope) and then got back on at US 14. They waited it out in the traffic, and we beat them back home by 10 minutes or so, meaning our detour saved us a grand total of about a half an hour. That was a Sunday afternoon. I concluded that I-35 is just too busy to be reduced to a single lane. MNDOT should do what NYSTA does and keep four lanes open for long-term projects.

HAI has now done a Zipper Merge video.

And all is right with the world.   :love: :D :love: :D :love: