Crash prone 'modern roundabouts'

[skluth]

^^
You should probably read the thread. Tradephoric and the rest of us have very carefully dissected the data behind roundabouts; it's not that cut and dry.

Consider this: the only thing forcing a driver to turn left or right is the steering wheel, not the geography surrounding the car.

"Carefully dissected" - Others might call it cherry-picked

[tradephoric]

The City of Dublin is making changes to the 161/Riverside Drive roundabout in mid-October.  The triple-lane roundabout has been plagued with a high number of crashes since it opened in August 2016.  A full year before the roundabout opened i had my doubts that the roundabout would be a success...

I have my doubts that the triple-lane roundabout currently under construction in Dublin, Ohio will see a reduction in total crashes (even though this is what the engineering manager of Dublin is predicting). Instead of learning from others mistakes, the City will forge ahead and construct it as a triple-lane roundabout.  A year later, the City will be perplexed why there are so many crashes at the roundabouts and hire a consultant to perform a safety audit.  The consultant, after being handed a big bag of money, will come to the conclusion that the roundabout should be reconfigured to a two-lane roundabout to reduce the total number of crashes.

Shortly after the roundabout opened the City of Dublin contracted Wisconsin firm MTJ Engineering for $29,046 to study the 161/Riverside roundabout.  After analyzing the roundabout they determined that a circulating lane should be removed on the northbound approach.  One report estimated the changes to the roundabout will cost the city $260,000 (that's in addition to the $29,046 contact with MTJ Engineering).  So all told, a few years after the roundabout opened, the city is spending nearly $300,000 to "fix" it.  Sounds like what i predicted would happen back in May 2015. 



Changes Scheduled for S.R. 161/Riverside Drive Roundabout
https://dublinohiousa.gov/construction-updates/changes-scheduled-for-s-r-161-riverside-drive-roundabout/

[jakeroot]

^^
You should probably read the thread. Tradephoric and the rest of us have very carefully dissected the data behind roundabouts; it's not that cut and dry.

Consider this: the only thing forcing a driver to turn left or right is the steering wheel, not the geography surrounding the car.

"Carefully dissected" - Others might call it cherry-picked

That might be a legitimate argument, if someone else would present some data. The only one doing that is Tradephoric. And he's limited to the cities that actually publish data and have roundabouts.

You're not the first person to accuse him of cherry-picking, but no one seems to be interested in actually disputing his data. The fact is that multi-lane roundabouts have a lot of crashes, and although they are not worse than signals, they don't seem to be any better at preventing serious injuries.

There's also a remarkable number of multi lane roundabouts that have had lanes removed (see above post); further evidence that they are not exactly good at preventing crashes when equipped with a lot of lanes.

[jamess]

Ive been reading this thread for a few years, but only just decided to sign up.

I used to be big on "team roundabout" but frankly, it feels like American traffic engineers have ruined them. They're supposed to be safer, but when you add more and more lanes, bypasses, and exits that allow 40mph+ movement, all those safety benefits evaporate.

That being said there is one roundabout project I am in favor of.

This monster near Trenton, NJ has just been replaced a modern version. Frankly, I don't understand how a licensed engineer could look at this and think "yes, this is safe."



Google:
https://goo.gl/maps/H393MejJZhp

Streetview has a mix of new and old, but you can move the slider around to find some gems.

Old:
https://goo.gl/maps/ZRXeQwYBvX52

New:
https://goo.gl/maps/BnKaRToQBzK2

[jakeroot]

Ahh, the hamburger roundabout. One of my favorites! Only driven through them in DC (the one by the Watergate, to be specific). They are still quite popular in the UK (and are still being built, eg. the Headington Roundabout near Oxford), though all examples I'm familiar with are signalized.

Any idea what the crash numbers were at that old intersection?

My only issue with the old intersection was the tiny waiting areas between carriageways. Wouldn't surprise me if a few crashes occurred when vehicles that were too long to fit in the waiting area blocked the prior intersection, causing a T-bone collision. Probably why so many of these were eventually signalized.

[johndoe]

That Carmel example where a through lane proceeds on the right of the bypass splitter made me wonder about speed control (narrowing the entry paths to discourage speeding and hopefully encourage yielding). 
Here are examples in Conway, Arkansas:

see more here: https://garverusa.com/services/transportation/projects/highway-286-widening-and-interchange-improvements

Here is an example in Victoria, B.C.:  https://goo.gl/maps/hDyb6ARYccM2

Has anyone seen other examples like this in North America?

[kalvado]

That Carmel example where a through lane proceeds on the right of the bypass splitter made me wonder about speed control (narrowing the entry paths to discourage speeding and hopefully encourage yielding). 
Here are examples in Conway, Arkansas:

see more here: https://garverusa.com/services/transportation/projects/highway-286-widening-and-interchange-improvements

Here is an example in Victoria, B.C.:  https://goo.gl/maps/hDyb6ARYccM2

Has anyone seen other examples like this in North America?

I hope if there are som - it is only in the south. A bit of snow, and you may kiss goodbye to the suspension... And plows would have hard time with those features as well - on top of the fact that roundabouts are rarely fully cleaned up anyway.

[jakeroot]

Here is an example in Victoria, B.C.:  https://goo.gl/maps/hDyb6ARYccM2

For what it's worth, the TAC (Transportation Association of Canada) considers that to be the first true turbo roundabout in North America.

Here's a short PDF chronicling its creation: https://goo.gl/6Hi1Qi

Note that the divider is flush with the ground, unlike the Arkansas example.

[tradephoric]

Ive been reading this thread for a few years, but only just decided to sign up.

I used to be big on "team roundabout" but frankly, it feels like American traffic engineers have ruined them. They're supposed to be safer, but when you add more and more lanes, bypasses, and exits that allow 40mph+ movement, all those safety benefits evaporate.

That being said there is one roundabout project I am in favor of.

This monster near Trenton, NJ has just been replaced a modern version. Frankly, I don't understand how a licensed engineer could look at this and think "yes, this is safe."



Google:
https://goo.gl/maps/H393MejJZhp

Streetview has a mix of new and old, but you can move the slider around to find some gems.

Old:
https://goo.gl/maps/ZRXeQwYBvX52

New:
https://goo.gl/maps/BnKaRToQBzK2

Welcome to the forums James.  I agree that American traffic engineers have over-complicated the modern roundabout by trying to add more and more circulating lanes.  Take Michigan for example... of the 7 triple-lane roundabouts constructed in the state since 2005; 4 of them have already been downsized to double-lane roundabouts (mainly due to the high number of crashes).  The three triple-lane roundabouts that remain are the #2, #4, and #5 most crash prone intersections in Michigan for 2017.  All told, the three triple-lane roundabouts accounted for 451 total crashes including 46 injury crashes last year.  It's one thing if these roundabouts were the #2, #4, and #5 most heavily traveled intersections in the state, but they aren't by a long shot. 

The fact that so many triple-lane roundabouts are downsized shortly after being constructed is evidence that something is wrong.  A few of them don't get downsized, and those are the ones where you see 150 crashes/year with exceedingly high crash rates.  I'm sure we've all heard that insanity is doing the same thing over and over again and expecting a different result... we gotta question why triple-lane roundabouts are still being constructed in this country when nearly every one turns into an unmitigated disaster! 

Top 5 crash prone intersections in Michigan (2017)
#1. 11 Mile Road/I-696 at Van Dyke Avenue in Warren/Center Line, Macomb County
194 total crashes, 32 injury crashes

#2. 18 ½ Mile Road at Van Dyke Avenue in Sterling Heights, Macomb County
165 total crashes, 13 injury crashes (triple-lane roundabout constructed in 2005)

#3. Telegraph Road at 12 Mile Road in Southfield, Oakland County
150 Total Crashes, 23 Injury Crashes

#4. Orchard Lake Road at 14 Mile road in Farmington Hills/West Bloomfield Township, Oakland County
144 total crashes, 24 Injury crashes (triple-lane roundabout constructed in 2015)

#5. Martin Parkway at Pontiac Trail in Commerce Township, Oakland County
142 total crashes, 9 injury crashes (triple-lane roundabout constructed in 2011)

[jamess]

From the previous page, this looks incredibly dangerous.

A pedestrian standing at the star needs to monitor 4 lanes of traffic before they can cross safely. Worse, the drivers at 1 and 2 will be looking only left and will take the first clear slot the accelerate straight into the crosswalk before confirming it is clear.

The crosswalk with the arrow has a triple threat, and the straight exit means vehicles will be accelerating quickly out of the circle.

Worse, the roundabout is designed so bicyclists exit the lane and use the crosswalks (note the ramps). Thats incredibly dangerous at the speeds this is designed for.

Incredibly irresponsible design.

[6a]

The City of Dublin is making changes to the 161/Riverside Drive roundabout in mid-October.  The triple-lane roundabout has been plagued with a high number of crashes since it opened in August 2016.  A full year before the roundabout opened i had my doubts that the roundabout would be a success...

I have my doubts that the triple-lane roundabout currently under construction in Dublin, Ohio will see a reduction in total crashes (even though this is what the engineering manager of Dublin is predicting). Instead of learning from others mistakes, the City will forge ahead and construct it as a triple-lane roundabout.  A year later, the City will be perplexed why there are so many crashes at the roundabouts and hire a consultant to perform a safety audit.  The consultant, after being handed a big bag of money, will come to the conclusion that the roundabout should be reconfigured to a two-lane roundabout to reduce the total number of crashes.

Shortly after the roundabout opened the City of Dublin contracted Wisconsin firm MTJ Engineering for $29,046 to study the 161/Riverside roundabout.  After analyzing the roundabout they determined that a circulating lane should be removed on the northbound approach.  One report estimated the changes to the roundabout will cost the city $260,000 (that's in addition to the $29,046 contact with MTJ Engineering).  So all told, a few years after the roundabout opened, the city is spending nearly $300,000 to "fix" it.  Sounds like what i predicted would happen back in May 2015. 



Changes Scheduled for S.R. 161/Riverside Drive Roundabout
https://dublinohiousa.gov/construction-updates/changes-scheduled-for-s-r-161-riverside-drive-roundabout/

I am not the least bit shocked by this development. While I generally don't mind roundabouts, this particular one is a pain in the ass. I've attached a visual representation of going through it during rush hour:

[NoGoodNamesAvailable]

From the previous page, this looks incredibly dangerous.

A pedestrian standing at the star needs to monitor 4 lanes of traffic before they can cross safely. Worse, the drivers at 1 and 2 will be looking only left and will take the first clear slot the accelerate straight into the crosswalk before confirming it is clear.

The crosswalk with the arrow has a triple threat, and the straight exit means vehicles will be accelerating quickly out of the circle.

Worse, the roundabout is designed so bicyclists exit the lane and use the crosswalks (note the ramps). Thats incredibly dangerous at the speeds this is designed for.

Incredibly irresponsible design.

Yeah, that is seriously awful. Not only is it a triple threat, but approaching drivers would have to stop in the roundabout, blocking both crossing lanes to be a safe distance from the crosswalk.

I don't understand why we accept things like this. It's borderline negligent. Considering how sparse the area looks, I'm sure setting the crosswalks a bit farther back and signalizing them wouldn't significantly disrupt traffic. Or if you're set on a design like this at least use raised crosswalks. Or literally any other treatment beyond the bare minimum.

[jakeroot]

Worse, the roundabout is designed so bicyclists exit the lane and use the crosswalks (note the ramps). Thats incredibly dangerous at the speeds this is designed for.

Some would say that bikes shouldn't be using the roundabouts to begin with. But that sets a dangerous precedent. Streets should be designed for everybody, not cars first and everybody else last (as is clearly the case here).

Is there accommodation? Yes, they didn't leave anyone out, but there has to be something better. I love underpasses for pedestrians and cyclists, but I'm not sure if that would work here given the water table. Overpasses are rather unsightly. Perhaps raising the roundabout and keeping the trails at ground level would have been an option. Yes that would be expensive, but cities have a duty to design an environment that is relatively equal to all modes. This is not an equal design.

Are there a lot of pedestrians in the area? Probably not, but who can blame them? I certainly wouldn't wanna walk through that mess.

[DaBigE]

Worse, the roundabout is designed so bicyclists can exit the lane and use the crosswalks (note the ramps).

Fixed that for you. Frankly, I don't know of a roundabout that has or can force a bicyclist to do anything except to make their own decision. As protected by most state laws, bicyclists have the right to "take the lane" and remain as a part of the motorized traffic flow or they can exit the roundabout and cross the approaches as a pedestrian.

[tradephoric]

That Carmel example where a through lane proceeds on the right of the bypass splitter made me wonder about speed control (narrowing the entry paths to discourage speeding and hopefully encourage yielding). 
Here are examples in Conway, Arkansas:

see more here: https://garverusa.com/services/transportation/projects/highway-286-widening-and-interchange-improvements

Here is an example in Victoria, B.C.:  https://goo.gl/maps/hDyb6ARYccM2

Has anyone seen other examples like this in North America?

I hope if there are som - it is only in the south. A bit of snow, and you may kiss goodbye to the suspension... And plows would have hard time with those features as well - on top of the fact that roundabouts are rarely fully cleaned up anyway.

There is already a disproportionately high number of fatal crashes at roundabouts involving motorcyclists and i question if this type of design with all that raised curbing would make things safer for them.  An interesting thing about the Conway roundabouts is that they were designed to accommodate three lanes of circulating traffic, yet they are initially stripped for two lanes.  Other triple-lane roundabouts that have been downsized to two-lanes often have their splitter islands modified as part of the reconfiguration to prevent the roundabout from being expanded to a triple-lane roundabout in the future (at least not without a tremendous cost).  After dealing with a triple-lane roundabout, some communities just know that they aren't going to try it again.

[jeffandnicole]

High speed, driver feel asleep, drink driver, truck with no brakes.... What a joke! That's an argument against 'something' but it has f#@$ all to do with roundabouts.

But they all hit something related to the design of the roundabout. Either a sign leading up to it, or the central island.

Would some of them have eventually crashed? Perhaps, but roundabouts create geographical hazards, which make them hard to navigate if you didn't notice them.

You can run a signal. You can't run a roundabout.

Based on the opinions of some in this thread, roundabouts need to be made idiot-proof, just because there's a good chance a law-breaker will be able to screw-up at a traffic light and make it through unscathed. What next, do we need to make electric fences that don't shock someone if they decide to pee on it? Lawyers and politicians are killing our society and whatever is left of "common sense".

As long as speeding, driving drunk, and inattentiveness aren't punishable by death, we should be trying to design for everyone, even morons. I fucking hate it. I'd rather we designed roads for only those with the intelligence to know how to properly operate vehicles, but that's not good PR. The best thing we can do? Make it a bit harder to get a licence. In the mean time, we can't seem to handle multi-lane roundabouts, or roundabouts with large objects in the middle.

Remember, roundabout and road designs aren't designed for just morons, but for those that become entangled with those morons.

Let's take the guardrail for example:  You are on a road.  You are driving perfectly fine.  Suddenly, someone T-bones you.  You hit the guardrail, which stops you from going down an embankment.  You were an innocent victim in the accident, but without that guardrail, you would've been a dead victim.  Thus, roads are designed not just to stop morons to fly off the road; they're designed to save the innocent victims as well.

Ive been reading this thread for a few years, but only just decided to sign up.

I used to be big on "team roundabout" but frankly, it feels like American traffic engineers have ruined them. They're supposed to be safer, but when you add more and more lanes, bypasses, and exits that allow 40mph+ movement, all those safety benefits evaporate.

That being said there is one roundabout project I am in favor of.

This monster near Trenton, NJ has just been replaced a modern version. Frankly, I don't understand how a licensed engineer could look at this and think "yes, this is safe."



Google:
https://goo.gl/maps/H393MejJZhp

Streetview has a mix of new and old, but you can move the slider around to find some gems.

Old:
https://goo.gl/maps/ZRXeQwYBvX52

New:
https://goo.gl/maps/BnKaRToQBzK2

Welcome!

To answer the question: Different times, and traffic was much lighter.  NJDOT did this a lot.  Along with this intersection, NJ 70/73 had a cut-thru, US 1 has a cut thru, etc.  And they still do it, such as with the Atlantic City Airport Circle.  Granted, this one was a bit different, but it worked surprisingly ok!

[jakeroot]

NJDOT did this a lot.  Along with this intersection, NJ 70/73 had a cut-thru, US 1 has a cut thru, etc.  And they still do it, such as with the Atlantic City Airport Circle.  Granted, this one was a bit different, but it worked surprisingly ok!

I was reading a story that locals already want the intersection modified to improve flow or something? I thought that was the point of the change?

[kphoger]

From the previous page, this looks incredibly dangerous.

A pedestrian standing at the star needs to monitor 4 lanes of traffic before they can cross safely. Worse, the drivers at 1 and 2 will be looking only left and will take the first clear slot the accelerate straight into the crosswalk before confirming it is clear.

The crosswalk with the arrow has a triple threat, and the straight exit means vehicles will be accelerating quickly out of the circle.

Worse, the roundabout is designed so bicyclists exit the lane and use the crosswalks (note the ramps). Thats incredibly dangerous at the speeds this is designed for.

Incredibly irresponsible design.

[in reply to the highlighted portion]

Then they are terrible drivers.  At one-way intersections (which is sort of what a roundabout entrance is), you should always look both ways for pedestrians.

[jeffandnicole]

NJDOT did this a lot.  Along with this intersection, NJ 70/73 had a cut-thru, US 1 has a cut thru, etc.  And they still do it, such as with the Atlantic City Airport Circle.  Granted, this one was a bit different, but it worked surprisingly ok!

I was reading a story that locals already want the intersection modified to improve flow or something? I thought that was the point of the change?

Which one?  The AC Airport circle definitely had some operational issues when it first opened, mostly due to traffic light timing.  I believe that was resolved.  As far as the Whitehorse Circle goes, I haven't heard of any issues, although I'm sure those that were used to having the right-of-way when entering the roundabout are peeved they now have to yield to those already in the roundabout.

[kalvado]

Then they are terrible drivers.  At one-way intersections (which is sort of what a roundabout entrance is), you should always look both ways for pedestrians.

How often you go through roundabouts?
If traffic is moderate or worse, you often have to take that gap - or wait till next gap shows up. Maybe.
A very quick glance right is the most you can do, often while already accelerating.
THat is what happens when you create race conditions, no protected phases whatsoever - and if you're in disadvantaged downstream position... Use it or loose it.

That is exactly why roundabouts may be a good idea for LIGHT traffic areas ONLY. 

[silverback1065]

those crosswalks are far enough back where that issue wouldnt likely happen.  anyway, here is a new beauty in greenwood, in

https://www.indystar.com/story/news/2018/10/09/greenwoods-new-roundabout-one-ups-carmel-adding-jug-handle/1565465002/

[jamess]

From the previous page, this looks incredibly dangerous.

A pedestrian standing at the star needs to monitor 4 lanes of traffic before they can cross safely. Worse, the drivers at 1 and 2 will be looking only left and will take the first clear slot the accelerate straight into the crosswalk before confirming it is clear.

The crosswalk with the arrow has a triple threat, and the straight exit means vehicles will be accelerating quickly out of the circle.

Worse, the roundabout is designed so bicyclists exit the lane and use the crosswalks (note the ramps). Thats incredibly dangerous at the speeds this is designed for.

Incredibly irresponsible design.

[in reply to the highlighted portion]

Then they are terrible drivers.  At one-way intersections (which is sort of what a roundabout entrance is), you should always look both ways for pedestrians.

Aren't you supposed to design for how people actually behave, and not how in a perfect world you would want them to behave?

[tradephoric]

here is a new beauty in greenwood, in

https://www.indystar.com/story/news/2018/10/09/greenwoods-new-roundabout-one-ups-carmel-adding-jug-handle/1565465002/

The pedestrian crosswalk crossing the south leg of Smith Valley Road and U.S. 31 is 180 feet long.  Assuming they are following MUTCD guidelines, when a pedestrian actuation occurs Smith Valley thru phase would need to run a minimum of 56 seconds to fit the pedestrian times.  That's just one phase... you still got to run U.S. 31 thru and U.S. 31 left turn phases.  The point is the cycle length at U.S. 31 and Smith Valley Road is going to be running pretty high.  I can't see how this triple-lane roundabout is going to function well when it's just a few hundred feet away from a major signalized intersection running a high cycle length.  Sure, the jug handle eliminates a dedicated left turn phase on Smith Valley Road, but it's still a 3-phase signal.  They design this complex intersection with bypasses, jug handles, and a complex triple-lane roundabout.. yet they still haven't eliminated dangerous left-turn movements at the U.S. 31/Smith Valley intersection?  With that much real estate to work with you think they could have come up with a better design. 

Silverback1065, do you live close to this intersection?   I'm really curious how long the Smith Valley thru phase runs when a pedestrian actuation occurs along that 180 foot crosswalk.  Maybe you could put a stopwatch to it!   

[silverback1065]

Haha I don't live too far from it.

[jakeroot]

NJDOT did this a lot.  Along with this intersection, NJ 70/73 had a cut-thru, US 1 has a cut thru, etc.  And they still do it, such as with the Atlantic City Airport Circle.  Granted, this one was a bit different, but it worked surprisingly ok!

I was reading a story that locals already want the intersection modified to improve flow or something? I thought that was the point of the change?

Which one?  The AC Airport circle definitely had some operational issues when it first opened, mostly due to traffic light timing.  I believe that was resolved.  As far as the Whitehorse Circle goes, I haven't heard of any issues, although I'm sure those that were used to having the right-of-way when entering the roundabout are peeved they now have to yield to those already in the roundabout.

The AC Airport Circle. Here's the story (from 2014): https://goo.gl/dypsJT

The pedestrian crosswalk crossing the south leg of Smith Valley Road and U.S. 31 is 180 feet long.  Assuming they are following MUTCD guidelines, when a pedestrian actuation occurs Smith Valley thru phase would need to run a minimum of 56 seconds to fit the pedestrian times...Silverback1065, do you live close to this intersection?   I'm really curious how long the Smith Valley thru phase runs when a pedestrian actuation occurs along that 180 foot crosswalk.  Maybe you could put a stopwatch to it!   

That would be beneficial for the roundabout right? Surprised you'd bring that up.

FWIW, I've seen four lane crossings here in WA that run 15-second walk cycles (3 walk, 12 don't walk), but sometimes extend if pedestrians are present. No idea how it knows. This is the intersection: https://goo.gl/hRkvAk (FYA-lockout when ped signal is active).