AARoads Forum

Please login or register.

Login with username, password and session length
Advanced search  

News:

New rules to ensure post quality. See this thread for details.

Author Topic: Why can't people merge onto an interstate properly anymore?  (Read 14017 times)

kphoger

  • *
  • Offline Offline

  • Posts: 21714
  • Location: Wichita, KS
  • Last Login: May 16, 2022, 05:07:49 PM
Re: Why can't people merge onto an interstate properly anymore?
« Reply #125 on: June 04, 2021, 02:42:07 PM »

I carpooled with a right lane runner one day and she just didn't not understand the concept of right lane running.  I tried to tell her that she is slowing traffic down.  She said but this lane is faster.  She said I can't understand why there is a back-up. 

The cause of the backup is all the traffic going through half the lane-space.
Logged
Keep right except to pass.  Yes.  You.
Visit scenic Orleans County, NY!
Male pronouns, please.

Quote from: Philip K. Dick
If you can control the meaning of words, you can control the people who must use them.

jemacedo9

  • *
  • Offline Offline

  • Posts: 780
  • Age: 49
  • Location: Phoenixville PA / Rochester NY
  • Last Login: May 16, 2022, 02:28:38 PM
Re: Why can't people merge onto an interstate properly anymore?
« Reply #126 on: June 04, 2021, 04:42:39 PM »

1. If traffic is free flowing with adequate spacing leading up to and/or at the merge point, then it's best to move over as soon as you can.
2. If traffic is stopped leading up to and/or up to the merge point, then it's best to use both lanes and zipper merge

The problem becomes when enough people move over early AND there is enough traffic to slow overall traffic down...that creates the situation where the closing lane is open and the continuing lane is jammed.  That is the least ideal situation in terms of safety, efficiency, and emotionally.  But the timing of when that occurs...the switchover from 1. to 2., is situational.

So to me...move over as soon as you can as long as traffic is free flowing...but when traffic volumes become high enough that slowdowns in the continuing lane begin, then a zipper merge should start right at that time, so that you don't end up with the least ideal situation.  I'm not sure if it can be any less complicated than that.
Logged

kphoger

  • *
  • Offline Offline

  • Posts: 21714
  • Location: Wichita, KS
  • Last Login: May 16, 2022, 05:07:49 PM
Re: Why can't people merge onto an interstate properly anymore?
« Reply #127 on: June 04, 2021, 04:48:03 PM »

1. If traffic is free flowing with adequate spacing leading up to and/or at the merge point, then it's best to move over as soon as you can.

Why is that best?

2. If traffic is stopped leading up to and/or up to the merge point, then it's best to use both lanes and zipper merge

Why is that best?
Logged
Keep right except to pass.  Yes.  You.
Visit scenic Orleans County, NY!
Male pronouns, please.

Quote from: Philip K. Dick
If you can control the meaning of words, you can control the people who must use them.

jakeroot

  • *
  • Offline Offline

  • Posts: 14671
  • Transportation Design

  • Age: 26
  • Location: Renton, WA / Vancouver, BC
  • Last Login: May 16, 2022, 11:26:24 PM
    • Flickr
Re: Why can't people merge onto an interstate properly anymore?
« Reply #128 on: June 04, 2021, 05:43:23 PM »

Most of the time around here, when traffic is light, distribution among two lanes of traffic that merge together seems to be fairly equal, with a slight favor towards the "continuing" lane.

Typically, this is what happens:

(1) traffic approaches the merge spaced however they were leading to that point
(2) when the merge signs appear, traffic begins to space out a bit
(3) by the time the merge is quite close, traffic has spaced enough that there are clear gaps into which the ending lane may merge into
(4) at the merge point or very slightly beforehand, drivers merge into those newly-formed gaps

I-705 to I-5 in Tacoma is where I see this behavior first-hand most frequently: during heavy traffic, during light traffic (note these are two adjacent time-frames in GSV, and were not cherry-picked).

This whole "move over as soon as you can" business is completely unnecessary because drivers (at least around here) naturally space out at the merge point to accommodate other drivers. Given the effects of rubber-band braking, this seems like the best option since it reduces the number of cars in one lane following closely (the case with merging early), thus reducing the chance of brake-tapping as drivers adjust to people merging early, and provides the maximum amount of time to drivers to adjust to those around them.
Logged
Check out my Flickr | Add me on Facebook!

kalvado

  • *
  • Offline Offline

  • Posts: 4633
  • Location: upstate NY
  • Last Login: May 16, 2022, 10:10:19 PM
Re: Why can't people merge onto an interstate properly anymore?
« Reply #129 on: June 04, 2021, 05:50:13 PM »

Most of the time around here, when traffic is light, distribution among two lanes of traffic that merge together seems to be fairly equal, with a slight favor towards the "continuing" lane.

Typically, this is what happens:

(1) traffic approaches the merge spaced however they were leading to that point
(2) when the merge signs appear, traffic begins to space out a bit
(3) by the time the merge is quite close, traffic has spaced enough that there are clear gaps into which the ending lane may merge into
(4) at the merge point or very slightly beforehand, drivers merge into those newly-formed gaps

I-705 to I-5 in Tacoma is where I see this behavior first-hand most frequently: during heavy traffic, during light traffic (note these are two adjacent time-frames in GSV, and were not cherry-picked).

This whole "move over as soon as you can" business is completely unnecessary because drivers (at least around here) naturally space out at the merge point to accommodate other drivers. Given the effects of rubber-band braking, this seems like the best option since it reduces the number of cars in one lane following closely (the case with merging early), thus reducing the chance of brake-tapping as drivers adjust to people merging early, and provides the maximum amount of time to drivers to adjust to those around them.
When the traffic is light, as you said. If total traffic is significantly less than what the lanes after merge can handle, then it doesn't really matter. Think about it - when can traffic space enough in general?

Logged

jakeroot

  • *
  • Offline Offline

  • Posts: 14671
  • Transportation Design

  • Age: 26
  • Location: Renton, WA / Vancouver, BC
  • Last Login: May 16, 2022, 11:26:24 PM
    • Flickr
Re: Why can't people merge onto an interstate properly anymore?
« Reply #130 on: June 04, 2021, 06:27:01 PM »

When the traffic is light, as you said. If total traffic is significantly less than what the lanes after merge can handle, then it doesn't really matter. Think about it - when can traffic space enough in general?

As provided in my GSV links, my point was also that the "take turns" style of merge persists no matter the traffic levels. The only difference is that the gaps are much smaller during heavy traffic, as traffic is going slower, but they're still large enough to accommodate a vehicle by the time you reach the physical taper; up to that point, traffic generally drivers bumper-to-bumper.

All things considered, the way things are done here strikes me as far more organized and friendlier than the chaos I witness in Virginia, which is one lane jammed with cars and the other (ending lane) having maybe a dozen cars spaced out trying to merge randomly into non-existent gaps. Around here, there is virtually no lane changing up to the merge point. There may as well be a barrier between the lanes; the rare early-merging driver is swiftly passed in the shoulder by traffic behind them on most occasions.
Logged
Check out my Flickr | Add me on Facebook!

kalvado

  • *
  • Offline Offline

  • Posts: 4633
  • Location: upstate NY
  • Last Login: May 16, 2022, 10:10:19 PM
Re: Why can't people merge onto an interstate properly anymore?
« Reply #131 on: June 04, 2021, 06:29:07 PM »

When the traffic is light, as you said. If total traffic is significantly less than what the lanes after merge can handle, then it doesn't really matter. Think about it - when can traffic space enough in general?

As provided in my GSV links, my point was also that the "take turns" style of merge persists no matter the traffic levels. The only difference is that the gaps are much smaller during heavy traffic, as traffic is going slower, but they're still large enough to accommodate a vehicle by the time you reach the physical taper; up to that point, traffic generally drivers bumper-to-bumper.

All things considered, the way things are done here strikes me as far more organized and friendlier than the chaos I witness in Virginia, which is one lane jammed with cars and the other (ending lane) having maybe a dozen cars spaced out trying to merge randomly into non-existent gaps. Around here, there is virtually no lane changing up to the merge point. There may as well be a barrier between the lanes; the rare early-merging driver is swiftly passed in the shoulder by traffic behind them on most occasions.
Again - difference between heavy and congested. Or you use those interchangeably?
Logged

kphoger

  • *
  • Offline Offline

  • Posts: 21714
  • Location: Wichita, KS
  • Last Login: May 16, 2022, 05:07:49 PM
Re: Why can't people merge onto an interstate properly anymore?
« Reply #132 on: June 04, 2021, 06:44:20 PM »

At this "form one lane" type merge that I use every day coming home from work, traffic on the right generally gives way to traffic on the left, despite traffic on the left having the YIELD sign.  At least, that's the case in normal traffic.  When traffic is backed up, people just take turns.  (Neither ramp is "more important" than the other, as both are coming from I-135 to US-54/400.)
Logged
Keep right except to pass.  Yes.  You.
Visit scenic Orleans County, NY!
Male pronouns, please.

Quote from: Philip K. Dick
If you can control the meaning of words, you can control the people who must use them.

jakeroot

  • *
  • Offline Offline

  • Posts: 14671
  • Transportation Design

  • Age: 26
  • Location: Renton, WA / Vancouver, BC
  • Last Login: May 16, 2022, 11:26:24 PM
    • Flickr
Re: Why can't people merge onto an interstate properly anymore?
« Reply #133 on: June 04, 2021, 06:51:18 PM »

When the traffic is light, as you said. If total traffic is significantly less than what the lanes after merge can handle, then it doesn't really matter. Think about it - when can traffic space enough in general?

As provided in my GSV links, my point was also that the "take turns" style of merge persists no matter the traffic levels. The only difference is that the gaps are much smaller during heavy traffic, as traffic is going slower, but they're still large enough to accommodate a vehicle by the time you reach the physical taper; up to that point, traffic generally drivers bumper-to-bumper.

All things considered, the way things are done here strikes me as far more organized and friendlier than the chaos I witness in Virginia, which is one lane jammed with cars and the other (ending lane) having maybe a dozen cars spaced out trying to merge randomly into non-existent gaps. Around here, there is virtually no lane changing up to the merge point. There may as well be a barrier between the lanes; the rare early-merging driver is swiftly passed in the shoulder by traffic behind them on most occasions.
Again - difference between heavy and congested. Or you use those interchangeably?

I don't think there is a need for distinction, at least for my example: cars in both lanes make gaps for each other throughout the day, regardless of the level of traffic. The only difference is the size of the gaps: smaller during peak hours, larger during off-peak hours. In either case, with rare exception, drivers are not blocking each other.

But for the record, yes, I was using those terms interchangeably. I generally use the term "busy" to describe lots of cars near the speed limit, reserving "heavy" or "congested" to describe peak-hour traffic.
Logged
Check out my Flickr | Add me on Facebook!

kalvado

  • *
  • Offline Offline

  • Posts: 4633
  • Location: upstate NY
  • Last Login: May 16, 2022, 10:10:19 PM
Re: Why can't people merge onto an interstate properly anymore?
« Reply #134 on: June 05, 2021, 12:54:11 PM »

When the traffic is light, as you said. If total traffic is significantly less than what the lanes after merge can handle, then it doesn't really matter. Think about it - when can traffic space enough in general?

As provided in my GSV links, my point was also that the "take turns" style of merge persists no matter the traffic levels. The only difference is that the gaps are much smaller during heavy traffic, as traffic is going slower, but they're still large enough to accommodate a vehicle by the time you reach the physical taper; up to that point, traffic generally drivers bumper-to-bumper.

All things considered, the way things are done here strikes me as far more organized and friendlier than the chaos I witness in Virginia, which is one lane jammed with cars and the other (ending lane) having maybe a dozen cars spaced out trying to merge randomly into non-existent gaps. Around here, there is virtually no lane changing up to the merge point. There may as well be a barrier between the lanes; the rare early-merging driver is swiftly passed in the shoulder by traffic behind them on most occasions.
Again - difference between heavy and congested. Or you use those interchangeably?

I don't think there is a need for distinction, at least for my example: cars in both lanes make gaps for each other throughout the day, regardless of the level of traffic. The only difference is the size of the gaps: smaller during peak hours, larger during off-peak hours. In either case, with rare exception, drivers are not blocking each other.

But for the record, yes, I was using those terms interchangeably. I generally use the term "busy" to describe lots of cars near the speed limit, reserving "heavy" or "congested" to describe peak-hour traffic.

Well, true, no strict need for distinction in this case. Specifically, as far as I understand you're discussing a short-range merge of approximately equally traveled roads, where basic fairness would dictate more or less equal merge priority within a pretty limited merge distance. This is somewhat unlike different scenarios - merge of two lanes (about equal priority, infinite merge distance) or a merge at freeway exit (limited distance, arguably lower priority for merging traffic, but more opportunities for through traffic to accommodate the merge) 
My pet question here is what strategy would achieve the highest throughput in different scenarios, and what would be the least stressful one. Of course, the highest throughput may not be the only metric as well
And that optimal strategy may depend on congested / non-congested flow and ability to switch from one strategy to the other once conditions change.
 
Logged

 


Opinions expressed here on belong solely to the poster and do not represent or reflect the opinions or beliefs of AARoads, its creators and/or associates.