Crash prone 'modern roundabouts'

Started by tradephoric, May 18, 2015, 02:51:37 PM

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tradephoric

A problem with the 14 Mile & Orchard Lake roundabout is that the traffic signal north of the roundabout is only 200 feet away.  This causes traffic to routinely queue up through the roundabout.



jakeroot

#2126
Quote from: DaBigE on May 30, 2019, 09:20:10 AM
Quote from: jakeroot on May 30, 2019, 02:10:55 AM
Quote from: DaBigE on May 29, 2019, 11:41:37 PM
You also have to remember that many of these systems, despite being on both sides of the carriageway, are fed by a common power conduit. One short upstream of the beacons, and neither one of them work.

That seems like it would be unusual, but I'll give you the benefit of the doubt. But consider this: how are we to say that the net-negative effects of an inoperable PTSWF sign are of greater significance than the net-positive effects of an operable PTSWF sign? Both in contrast to not having a sign at all.

I think you're making this a lot more complicated than it needs to be. Just let them flash constantly. What does it hurt? It also simplifies the wiring and programming needs. Having 24/7 flash and no sign has a better/safer driver default response than with the PTSWF. One could also say the part-time flash and sign is not necessary, as being prepared to possibly have to stop should be assumed with the Signal Ahead warning sign.

I don't fully understand the point of a constant flashing yellow light, with regards to warning of an upcoming signal. Signals should be fairly obvious, as long as the heads are placed adequately well. Plus, a constant flashing yellow light doesn't tell you anything about the state of the signal. On high-speed roads, which is really the only place where these are even remotely useful, it would be nice to know if you have to prepare to stop from 50 or 60 miles per hour.

The primary argument I see against PTSWF signs is that drivers speed up when they see them. I'm not going to question whether or not that's accurate, but here's another metric to consider: are there more accidents caused by speeding up to make a light, then there are because of drivers making a "poor decision" while in the dilemma zone? Such as slamming on the brakes, and causing a rear-end collision.

I'm not sure it's fair to say that I'm being pedantic or something. Well-engineered highways can easily be measured not just by how many cars they push through, but by how safe they are. There are positives and negatives to every decision. It's not black and white. A good engineer will consider every outcome, and the positives and negatives of each of those outcomes.

For the record, I wouldn't say that the jury is out on these types of signs. There are plenty of areas that use them, and justify them on account of improved safety.

ScottRAB

Quote from: kphoger on May 29, 2019, 04:43:20 PM
Quote from: TheHighwayMan394 on May 29, 2019, 04:36:52 PM

Quote from: tradephoric on May 29, 2019, 04:16:03 PM

Quote from: TheHighwayMan394 on May 29, 2019, 03:32:37 PM
Here we are again. It's the roundabout's fault the woman was drunk and speeding.

With your logic there is no need to convert traffic signals to roundabouts in the first place.  When a drunk driver blows through a red light it's not the red lights fault they were drunk and speeding.  Why are we worried about fatal t-bone accidents at traffic signals when alcohol was a factor?  After all, you can't stop stupid. 

With the roundabout that dramatically minimizes the chances this lady would have plowed into someone else.

How?  A driver crossing her path in the roundabout is (roughly) no less at a 90° angle to the other driver than one crossing a stoplighted intersection.  I guess she was less likely to hit someone on the far side of the roundabout...

Modern roundabouts force drivers to slow down and change the angle of interaction.  It is no longer 90 degrees at a modern roundabout, but usually about 60 degrees. 
Modern Roundabouts are one of several proven road safety features (FHWA). 
The life saved may be your own.
https://safety.fhwa.dot.gov/provencountermeasures/roundabouts/
https://safety.fhwa.dot.gov/intersection/innovative/roundabouts/

kphoger

Quote from: ScottRAB on May 31, 2019, 01:44:22 PM
Modern roundabouts force drivers to slow down and change the angle of interaction.

You're new, so we can forgive you.  But this has been hashed to death already.

Here is an example post.
Keep right except to pass.  Yes.  You.
Visit scenic Orleans County, NY!
Male pronouns, please.

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

jakeroot

I wish we'd stop this notion of "force". You can't force drivers to go around in a circle, if they don't want to.

kalvado

Quote from: ScottRAB on May 31, 2019, 01:44:22 PM
Modern roundabouts force drivers to slow down and change the angle of interaction.  It is no longer 90 degrees at a modern roundabout, but usually about 60 degrees. 
Modern Roundabouts are one of several proven road safety features (FHWA). 
The life saved may be your own.
https://safety.fhwa.dot.gov/provencountermeasures/roundabouts/
https://safety.fhwa.dot.gov/intersection/innovative/roundabouts/
Oh, duckspeak... Something I was really missing... not.
Modern roundabout encourage slowdown when driver is in full control; making consequences worse when driver is not prepared or not acting (drunk, sleepy, inattentive, drives in reduced visibility, runaway car etc). Impact would no longer be 90 degree side, but vehicle will be pushed up by curbs, helping it to  roll-off or impact higher on cross traffic, creating potential of high level impact, for which most vehicles are not tested or certified.
Modern Roundabouts are great when not designed by idiots.
The life lost may be your own.


kphoger

Quote from: ScottRAB on May 31, 2019, 01:44:22 PM

Quote from: kphoger on May 29, 2019, 04:43:20 PM
A driver crossing her path in the roundabout is (roughly) no less at a 90° angle to the other driver than one crossing a stoplighted intersection.  I guess she was less likely to hit someone on the far side of the roundabout...

Modern roundabouts force drivers to slow down and change the angle of interaction.  It is no longer 90 degrees at a modern roundabout, but usually about 60 degrees. 

Let me try this again.  My post was in reply to a comment made about an news article shared by tradephoric.  Did you read that article?  In that article, it was stated that a drunk driver vaulted over the center of a roundabout and landed on the other side.  My point is that her vehicle–which apparently didn't undergo much deflection–was indeed at roughly a 90° angle to any vehicle crossing her immediate path.  Below is the specific roundabout at which this crash happened.  That ain't no 60° impact point.

Keep right except to pass.  Yes.  You.
Visit scenic Orleans County, NY!
Male pronouns, please.

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

ErmineNotyours


DaBigE

Quote from: jakeroot on May 30, 2019, 06:45:23 PM
Quote from: DaBigE on May 30, 2019, 09:20:10 AM
Quote from: jakeroot on May 30, 2019, 02:10:55 AM
Quote from: DaBigE on May 29, 2019, 11:41:37 PM
You also have to remember that many of these systems, despite being on both sides of the carriageway, are fed by a common power conduit. One short upstream of the beacons, and neither one of them work.

That seems like it would be unusual, but I'll give you the benefit of the doubt. But consider this: how are we to say that the net-negative effects of an inoperable PTSWF sign are of greater significance than the net-positive effects of an operable PTSWF sign? Both in contrast to not having a sign at all.

I think you're making this a lot more complicated than it needs to be. Just let them flash constantly. What does it hurt? It also simplifies the wiring and programming needs. Having 24/7 flash and no sign has a better/safer driver default response than with the PTSWF. One could also say the part-time flash and sign is not necessary, as being prepared to possibly have to stop should be assumed with the Signal Ahead warning sign.

I don't fully understand the point of a constant flashing yellow light, with regards to warning of an upcoming signal. Signals should be fairly obvious, as long as the heads are placed adequately well.

Based on the bolded statement, the advanced warning should not even be necessary then. And if the traffic signal uses LEDs, unless the intersection is at the end of a long, sweeping curve, you should be able to see the signal before you even reach the advanced warning sign.

QuotePlus, a constant flashing yellow light doesn't tell you anything about the state of the signal. On high-speed roads, which is really the only place where these are even remotely useful, it would be nice to know if you have to prepare to stop from 50 or 60 miles per hour.

Why do you need to know this? If that was indeed true, it should be used on every rural railroad crossing warning sign as well. One of the points of posting the Signal Ahead warning sign is to indicate that the driver may need to prepare to stop. Meaning: You might want to take your foot off the gas and hover over the brake so you can react appropriately. Unless you're going uphill, (which would work in your favor anyway), momentum loss will be minimal. In any case, as I said above, with LED indications, the state of the signal is known before the motorist even reaches the sign, as long as the driver's head isn't buried in their smartphone.
"We gotta find this road, it's like Bob's road!" - Rabbit, Twister

tradephoric

#2134
^There are some examples of "Prepare To Stop When Flashing" signs along high speed arterials in Metro Detroit.  They can definitely be useful to truckers to let them know when to let off the gas so they don't get stuck in the "dilemma zone".  You most often see this when the approaching light is obscured and/or when there is a steep downhill grade at the signal.

https://www.google.com/maps/@42.52658,-83.2852535,3a,75y,5.79h,90.72t/data=!3m6!1e1!3m4!1sC-LKWk2JpmHjJf0ZQxloQQ!2e0!7i16384!8i8192

https://www.google.com/maps/@42.505621,-83.3168609,3a,75y,311.39h,89.76t/data=!3m6!1e1!3m4!1s-yO0DtGscg9Qb9P6nmCMng!2e0!7i16384!8i8192

Here's a location that could really use an advanced flasher.  There is a sign at the top of the hill that states "SIGNAL AHEAD WATCH FOR STOPPED TRAFFIC" but it doesn't give drivers any advanced warning when the signal is going to change to red. 
https://www.google.com/maps/@42.7055439,-83.2426771,3a,75y,180.1h,86.94t/data=!3m6!1e1!3m4!1spJ2LL1OR31uawWNE16FNtQ!2e0!7i16384!8i8192

jeffandnicole

Quote from: DaBigE on June 03, 2019, 01:56:19 AM
Quote from: jakeroot on May 30, 2019, 06:45:23 PM
I don't fully understand the point of a constant flashing yellow light, with regards to warning of an upcoming signal. Signals should be fairly obvious, as long as the heads are placed adequately well.

Based on the bolded statement, the advanced warning should not even be necessary then. And if the traffic signal uses LEDs, unless the intersection is at the end of a long, sweeping curve, you should be able to see the signal before you even reach the advanced warning sign.

Here's an example of a signal that isn't seen from the normal distance of the sign. Plus, there's an overpass, and the light is located as one is going downhill.

https://goo.gl/maps/xFiQGnBsHzbDvTgVA

Otherside of the overpass: Still don't see the light.  https://goo.gl/maps/8nVnfqFxo8QkbLW88

Finally, as you moved around the curve: The light is now visible. https://goo.gl/maps/vB5J9wHBUt8GsP7FA

True, it would be more useful to have a 'Red Light When Flashing' type signage here, which they have at other places on the road, including just a mile or so away.  May have something to do with traffic volumes and such as well to determine what type of signage or beacon is warranted.

QuotePlus, a constant flashing yellow light doesn't tell you anything about the state of the signal. On high-speed roads, which is really the only place where these are even remotely useful, it would be nice to know if you have to prepare to stop from 50 or 60 miles per hour.

50 mph is high speed?  Was this written by the IIHS?

DaBigE

Quote from: tradephoric on June 03, 2019, 07:50:54 AM
There is a sign at the top of the hill that states "SIGNAL AHEAD WATCH FOR STOPPED TRAFFIC" but it doesn't give drivers any advanced warning when the signal is going to change to red
https://www.google.com/maps/@42.7055439,-83.2426771,3a,75y,180.1h,86.94t/data=!3m6!1e1!3m4!1spJ2LL1OR31uawWNE16FNtQ!2e0!7i16384!8i8192

Neither do the vast majority of traffic signals in the US. Heaven forbid a driver has to, gasp, pay attention. No warning? Last I saw, that was the whole reason why the yellow light was added to the traffic signal setup.
"We gotta find this road, it's like Bob's road!" - Rabbit, Twister

tradephoric

Quote from: DaBigE on June 03, 2019, 09:04:31 AM
Neither do the vast majority of traffic signals in the US. Heaven forbid a driver has to, gasp, pay attention. No warning? Last I saw, that was the whole reason why the yellow light was added to the traffic signal setup.

Just because there aren't advanced warning signs/flashers approaching the vast majority of traffic signals doesn't mean they are never warranted.  A gravel-hauler driver running up and down the road every day may realize they are approaching a traffic signal, but a static sign (or constant flashing beacon) won't tell them when that signal is about to turn red (which could be useful info as they are approaching the traffic signal cruising down a 10% downgrade at 50 mph with a loaded trailer).  I don't have a problem with having a handful of advanced warning flashers at traffic signals in a metro region of 4 million people, but apparently DaBigE doesn't like that. 

DaBigE

Quote from: tradephoric on June 03, 2019, 09:51:57 AM
Quote from: DaBigE on June 03, 2019, 09:04:31 AM
Neither do the vast majority of traffic signals in the US. Heaven forbid a driver has to, gasp, pay attention. No warning? Last I saw, that was the whole reason why the yellow light was added to the traffic signal setup.

Just because there aren't advanced warning signs/flashers approaching the vast majority of traffic signals doesn't mean they are never warranted.  A gravel-hauler driver running up and down the road every day may realize they are approaching a traffic signal, but a static sign (or constant flashing beacon) won't tell them when that signal is about to turn red (which could be useful info as they are approaching the traffic signal cruising down a 10% downgrade at 50 mph with a loaded trailer).  I don't have a problem with having a handful of advanced warning flashers at traffic signals in a metro region of 4 million people, but apparently DaBigE doesn't like that.

Surprise, surprise, you twist my words yet again. I didn't say they were never warranted. Approaches along horizontal curves? Likely needed. Vertical curves? Depends on the magnitude of the curve. On a straightaway with adequate sight distance? Shouldn't be needed, but would be a treatment to address higher than expected rear-end crash rates. Better? What I actually don't like is creating a nanny-state of drivers who are incapable of thinking for themselves because they only know how to act when told what to do. Don't know when/if a traffic light is going to change? Prepare for it. Did defensive driving go out the window with common sense? Worst case scenario, you loose a couple mph for a couple hundred feet.
"We gotta find this road, it's like Bob's road!" - Rabbit, Twister

jakeroot

Quote from: DaBigE on June 03, 2019, 01:56:19 AM
Quote from: jakeroot on May 30, 2019, 06:45:23 PM
I don't fully understand the point of a constant flashing yellow light, with regards to warning of an upcoming signal. Signals should be fairly obvious, as long as the heads are placed adequately well.

Based on the bolded statement, the advanced warning should not even be necessary then. And if the traffic signal uses LEDs, unless the intersection is at the end of a long, sweeping curve, you should be able to see the signal before you even reach the advanced warning sign.

If there is a signal around a long, sweeping curve, certainly even the most well-placed signal will not do drivers any good. Unless the expectation is that drivers must proceed around a corner at such a stupidly-low speed as to be able to stop at a potential red light, drivers on high speed, sparsely-signalized roads should be able to proceed at-speed without needing to worry about a traffic light. The "prepare to stop when flashing" sign is very helpful in this scenario, as it permits drivers to focus more on other potential hazards, and not whether or not they'll need to suddenly make an emergency stop around the next bend.

Quote from: DaBigE on June 03, 2019, 11:47:59 AM
Better? What I actually don't like is creating a nanny-state of drivers who are incapable of thinking for themselves because they only know how to act when told what to do. Don't know when/if a traffic light is going to change? Prepare for it. Did defensive driving go out the window with common sense? Worst case scenario, you loose a couple mph for a couple hundred feet.

We have to pander to that 1% of drivers who ruin it for the rest of us. Like those that push every single dilemma-zone situation, to the point where they consistently enter well after the yellow has expired (sometimes late enough to cause side-street drivers to delay movement).

Rant: The job of an engineer or designer is not to create situations where drivers have to put in a great deal of effort to avoid crashing. Fact is, at least in America, there are a lot of drivers who only drive because they have to, not because they want to. Those particular drivers likely have never heard of "defense driving". They don't expect lights to change. They don't even know why lights change. All they know is, they missed the light and now they're annoyed (or late). If you've ever driven with anyone who you'd categorize as someone who "doesn't like driving", they're probably the same people who consistently complain about everything on the road. Why? Because they don't understand how driving works. They don't know what a "stale green light" is; lights are either red, yellow, or green: green means go, yellow means "make a call", and red means stop. That's the extent of their knowledge for lights, other than "left turns yield" (which is still screwed up by fair number of drivers).

What's my point in all this? It's not completely pointless to offer drivers a hand. Most of them probably need it, anyhow.

DaBigE

Quote from: jakeroot on June 03, 2019, 11:00:01 PM
Rant: The job of an engineer or designer is not to create situations where drivers have to put in a great deal of effort to avoid crashing. Fact is, at least in America, there are a lot of drivers who only drive because they have to, not because they want to. Those particular drivers likely have never heard of "defense driving". They don't expect lights to change. They don't even know why lights change. All they know is, they missed the light and now they're annoyed (or late). If you've ever driven with anyone who you'd categorize as someone who "doesn't like driving", they're probably the same people who consistently complain about everything on the road. Why? Because they don't understand how driving works. They don't know what a "stale green light" is; lights are either red, yellow, or green: green means go, yellow means "make a call", and red means stop. That's the extent of their knowledge for lights, other than "left turns yield" (which is still screwed up by fair number of drivers).

Which also highlights how piss poor our driver's education is in the US. This is all stuff a good driver's education course should cover. I still have memories my old driver's ed teacher asking the question "is that green light stale?" He would do it before every traffic light we encountered. If I were king for a day, everyone would have to have training to the level of a CDL, at a minimum and would have to retest on a regular basis.
"We gotta find this road, it's like Bob's road!" - Rabbit, Twister

jakeroot

Quote from: DaBigE on June 04, 2019, 08:58:05 AM
Quote from: jakeroot on June 03, 2019, 11:00:01 PM
Rant: The job of an engineer or designer is not to create situations where drivers have to put in a great deal of effort to avoid crashing. Fact is, at least in America, there are a lot of drivers who only drive because they have to, not because they want to. Those particular drivers likely have never heard of "defense driving". They don't expect lights to change. They don't even know why lights change. All they know is, they missed the light and now they're annoyed (or late). If you've ever driven with anyone who you'd categorize as someone who "doesn't like driving", they're probably the same people who consistently complain about everything on the road. Why? Because they don't understand how driving works. They don't know what a "stale green light" is; lights are either red, yellow, or green: green means go, yellow means "make a call", and red means stop. That's the extent of their knowledge for lights, other than "left turns yield" (which is still screwed up by fair number of drivers).

Which also highlights how piss poor our driver's education is in the US. This is all stuff a good driver's education course should cover. I still have memories my old driver's ed teacher asking the question "is that green light stale?" He would do it before every traffic light we encountered. If I were king for a day, everyone would have to have training to the level of a CDL, at a minimum and would have to retest on a regular basis.

Oh I know it. Our driver education is hilariously bad. Maybe not as bad as India, but complete shit compared to the UK, Australia, etc. Hell, Canada seems to have better education, by quite a bit. BC (ICBC) even requires those "L" and "N" stickers that you see in some other countries. Very comprehensive.

Problem is, the motorists lobbies will almost certainly push back, citing how reliant people are on cars, and how this is part of the "war on cars", that we can't expect people to operate to CDL-capacity, etc. All BS as far as I'm concerned, but that's the stand they'll take. They should be ignored, but, well, politics.

doorknob60

Quote from: jakeroot on May 29, 2019, 05:24:27 PM
WSDOT is building two new roundabouts near Camas (just north of the Columbia River) along WA-14. Construction started today. The two intersections are roughly at either end of this Maps link (15 St/Washougal River Rd, and 32 St).

These are relatively simple one-lane roundabouts (with one extra lane at 32 St), but what is more worrisome for me, is that they're being built just east of a brand new freeway interchange. WA-14 is basically a freeway or Super-2 from I-5 (16 miles away), all the way to this point. This would not be the first roundabout at the terminus of a freeway, but it doesn't seem like that great of an idea to me. WA-14 is either 55 or 60 from I-5, up to 15 St (the first roundabout).

I'm not trying to imply that a signal would absolutely be better. But I would assume that a signal, with a flashing "prepare to stop" message and rumble strips perpendicular to the lanes, would be better than a roundabout, as those really can sneak up on you, if you're not expecting them (which people may not be, after driving along 16 miles worth of divided highway).



I'm a fan of roundabouts generally (I used to live in Bend, so I'm very experienced to say the least), but that seems like a really bad place. I've driven on that section of SR-14 a handful of times, since I visit family in Trout Lake, WA a couple times a year usually. I always assumed they were planning on extending the freeway/super 2 through the rest of Washougal. This is a road where people are used to ~55 MPH free flowing traffic on both sides, so this seems like a mistake. The lights already there are not ideal, but can at least accommodate traffic at (or near) the speed limit most of the time.

DaBigE

Well, besides causing crashes, apparently roundabouts are causing tornaders...er tornadoes: https://www.phillyvoice.com/pennsylvania-traffic-circles-causing-tornadoes-weather-2019/  :hmmm:
"We gotta find this road, it's like Bob's road!" - Rabbit, Twister

MNHighwayMan

Quote from: DaBigE on June 06, 2019, 10:17:52 AM
Well, besides causing crashes, apparently roundabouts are causing tornaders...er tornadoes: https://www.phillyvoice.com/pennsylvania-traffic-circles-causing-tornadoes-weather-2019/  :hmmm:

Now we know where tradephoric lives. :bigass:

tradephoric

Quote from: DaBigE on June 06, 2019, 10:17:52 AM
Well, besides causing crashes, apparently roundabouts are causing tornaders...er tornadoes: https://www.phillyvoice.com/pennsylvania-traffic-circles-causing-tornadoes-weather-2019/  :hmmm:

If you have watched any Nascar races you have probably heard Darrell Waltrip talking about the "vortex theory".  The theory goes that race cars racing around an oval track creates a "vortex" that repels approaching storms.  DW swears by it! 

jakeroot

Quote
The segment picked up steam on social media Sunday, and then again Wednesday. Here's hoping the momentum from all those retweets doesn't start a tornado.

Well played, Mr Hermann. Well played....

tradephoric

A report from the Mid-Ohio Regional Planning Commission released in 2016 found that the Main Street and Cemetery roundabout (constructed in 2011) had the most reported accidents in Hilliard, 233, from 2013 through 2015.  Based on their report, the city of Hilliard approved a $160,000 contract with Burgess & Niple, the same company that originally designed the roundabout to begin with, to come up with solutions to reduce the high crash rate at that roundabout .  In March the city counsel approved a contract with Strawser Paving Co. for $544,000 to make modifications to the roundabouts along Main Street.  None of the changes listed in the article include eliminating circulating lanes of traffic so we will see how effective the changes will be. 

It must be nice working at Burgess & Niple, getting awarded a $160,000 contract to redesign a problem roundabout that they had originally designed years earlier.  And the firm didn't even come up with a design that eliminates circulating lanes inside the roundabouts, which has historically been the only long term fix to reducing the crash rates at these problem roundabouts.

Hilliard's summer roadwork includes Main Street roundabouts
https://www.dispatch.com/news/20190611/hilliards-summer-roadwork-includes-main-street-roundabouts

kphoger

Quote from: tradephoric on June 17, 2019, 02:20:22 PM
And the firm didn't even come up with a design that eliminates circulating lanes inside the roundabouts, which has historically been the only long term fix to reducing the crash rates at these problem roundabouts.

If that has indeed been established by your own research in this thread, does the firm even know that's the case?
Keep right except to pass.  Yes.  You.
Visit scenic Orleans County, NY!
Male pronouns, please.

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

6a

They've already started work in that area (I live in Hilliard) but I don't know what good it would do to reduce the number of lanes in the roundabouts. Every road leading into them is 4 lanes; one of which (Cemetery) is a direct feed off I-270. I've never personally experienced any issue going through them, but stats are stats.

I have absolutely no citations to back this up, only word of mouth, but it was widely believed that when these roundabouts were designed, school bus traffic wasn't taken into consideration.



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