Crash prone 'modern roundabouts'

[lordsutch]

For reference, this is what the intersection is now while Google still has the old layout.

Plop down any sort of at-grade intersection in the middle of what is effectively a freeway (fully grade-separated dual carriageway, what is now being called an "expressway" in England, which really is just a freeway with somewhat relaxed design standards and no legal restriction on non-motor vehicle users, even though they are highly discouraged) without adequate warning and you'll get lots of wrecks.

See also the SABRE thread, https://www.sabre-roads.org.uk/forum/viewtopic.php?f=1&t=37936:

Apparently the problems were as such:
- minimal signage that didn't make the approach obvious
- the street lighting wasn't switched on until several days after the roundabout opened
- the roundabout is kerb height, so again, isn't obvious on its approach
- no rumble strips

I leave it as an exercise for the reader to decide what would happen if you put a four-way signalized intersection in the middle of a road signed for and designed for 70 mph, where previously there was a free-flow ramp, with no advance warning signs or lighting.

(BTW if you zoom out you can see the road is part of a cut-off between two major freeway-class roads, the A50 - which was originally intended to be a full motorway, the M64 - and A38. Basically the local authority did the equivalent of dumping a new at-grade in the middle of SC 277 between I-20 and I-77 so a few houses would have direct access to SC 277.)

[kalvado]

For reference, this is what the intersection is now while Google still has the old layout.

Plop down any sort of at-grade intersection in the middle of what is effectively a freeway (fully grade-separated dual carriageway, what is now being called an "expressway" in England, which really is just a freeway with somewhat relaxed design standards and no legal restriction on non-motor vehicle users, even though they are highly discouraged) without adequate warning and you'll get lots of wrecks.

See also the SABRE thread, https://www.sabre-roads.org.uk/forum/viewtopic.php?f=1&t=37936:

Apparently the problems were as such:
- minimal signage that didn't make the approach obvious
- the street lighting wasn't switched on until several days after the roundabout opened
- the roundabout is kerb height, so again, isn't obvious on its approach
- no rumble strips

I leave it as an exercise for the reader to decide what would happen if you put a four-way signalized intersection in the middle of a road signed for and designed for 70 mph, where previously there was a free-flow ramp, with no advance warning signs or lighting.

But... But... But this is roundabout, greatest and bestest thing ever!!!! There is no way  there would be any problem!!!

[lordsutch]

But... But... But this is roundabout, greatest and bestest thing ever!!!! There is no way  there would be any problem!!!

Strawman much?

[kalvado]

But... But... But this is roundabout, greatest and bestest thing ever!!!! There is no way  there would be any problem!!!

Strawman much?

No, just enjoying the show. Too bad innocent cars were damaged, not careers...

[jakeroot]

But... But... But this is roundabout, greatest and bestest thing ever!!!! There is no way  there would be any problem!!!

Strawman much?

No, just enjoying the show. Too bad innocent cars were damaged, not careers...

No, that was a strawman. Don't try and weasel your way out now.

[6a]

Presented without comment:

[tradephoric]

Accidents at Dublin's 161/Riverside roundabout jumped from 20 accidents before the roundabout to 156 after the roundabout.  Dublin engineers already have plans to eliminate a circulating lane through the roundabout to address the high number of accidents.  Not like anyone could have predicted this would happen though... 

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).

Dublin Built A Traffic Circle To Reduce Accidents. The Opposite Happened
In 2014, before the roundabout, there were 20 accidents at the intersection. In the past year, that jumped to 156 accidents..
http://radio.wosu.org/post/dublin-built-traffic-circle-reduce-accidents-opposite-happened#stream/0

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.

Riverside-161 roundabout design being reviewed
Dublin officials said they are taking a closer look at the city's largest roundabout to see whether any adjustments are needed to improve driver safety.  The city has a $29,046 contract with Wisconsin firm MTJ Engineering to study the state Route 161-Riverside Drive roundabout.
http://www.thisweeknews.com/news/20170214/riverside-161-roundabout-design-being-reviewed

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.

Engineers and police analyzed the roundabout design, and will change one busy entry point.  "The northbound lane configuration will become, the left lane will be left turn or straight through," O'Callaghan says. "The center lane will be straight only. And there will be a dedicated right-turn only lane."  Officials hope the changes will greatly reduce the number of crashes.  But it will cost $260,000.

[tradephoric]

Jeannie Willis predicted there would be a reduction in crash frequency at the SR 161 / Riverside roundabout.  It turns out there has been 166 crashes at the roundabout in the first 9 months.  Compare that to just 20 crashes per year before the roundabout.  It's surprising that Jeannie didn't see this coming... all she had to do was look at the crash records of any triple-lane roundabout constructed in America to realize they are crash prone.  At least they are attempting to fix the mess they created.

Proposed changes for Dublin roundabout to take place in fall
http://www.10tv.com/article/proposed-changes-dublin-roundabout-take-place-fall

"The roundabout is actually operating fairly well on all of the approaches except the northbound approach," said Jeannie Willis, engineering manager for City of Dublin. "That seems to be where our drivers are getting the most confused."

"We did not expect to see anything like this. Safety is Dublin's number one priority," said Willis.

"We came to realize simplifying the decision making for the driver approaching the roundabout would help things out quite a bit," said Willis.

[tradephoric]

It only took about two months for a driver to destroy Saegertown's new roundabout...  'Shakayla Shantel Deible ran her car into the masonry wall in the center of the roundabout on Main Street.  Authorities say she appeared to be under the influence of alcohol and drugs and will be charged based on the results of blood tests.'

June 12, 2017 - Saegertown's southern roundabout opens to traffic
http://www.yourerie.com/news/local-news/saegertowns-southern-roundabout-opens-to-traffic/739056574

Aug 22, 2017 - Woman destroys new roundabout in Saegertown
http://www.yourerie.com/news/local-news/woman-destroys-new-roundabout-in-saegertown/795648083

[tradephoric]

Another semitruck has tipped over at the 37th Street and Highway 275 roundabout in Nebraska, two months to the day that a semitrailer loaded with hogs tipped over in the roundabout back on June 22nd.  The roundabout opened in November 2016 and has already been the site of 2 tip-overs. 

Truck tips in roundabout
http://norfolkdailynews.com/news/truck-tips-in-roundabout/article_28e040c4-8777-11e7-a7e2-1f180cd69b14.html

[kalvado]

It only took about two months for a driver to destroy Saegertown's new roundabout...  'Shakayla Shantel Deible ran her car into the masonry wall in the center of the roundabout on Main Street.  Authorities say she appeared to be under the influence of alcohol and drugs and will be charged based on the results of blood tests.'

June 12, 2017 - Saegertown's southern roundabout opens to traffic
http://www.yourerie.com/news/local-news/saegertowns-southern-roundabout-opens-to-traffic/739056574

Aug 22, 2017 - Woman destroys new roundabout in Saegertown
http://www.yourerie.com/news/local-news/woman-destroys-new-roundabout-in-saegertown/795648083

Destroy is a big word here. A roll or two of duck tape - and the thing would be as ugly as it was the day before accident...

[tradephoric]

The animation for the 37th Street and US Hwy 275 in Norfolk, Nebraska is all wrong.  It doesn't show the semi-trucks flipping over on their sides.

[jakeroot]

The animation for the 37th Street and US Hwy 275 in Norfolk, Nebraska is all wrong.  It doesn't show the semi-trucks flipping over on their sides.

I went through a roundabout just a few days ago right behind a truck. It didn't flip over.

[jeffandnicole]

A truck tipped over today on the Interchange 4 on-ramp to the NJ Turnpike. We need to ban highway on-ramps.

[tradephoric]

A truck tipped over today on the Interchange 4 on-ramp to the NJ Turnpike. We need to ban highway on-ramps.

Trucks seemingly have a higher propensity to rolling over at roundabouts than at signalized intersections.  That's the point you are ignoring when you argue that trucks tip over on the NJ Turnpike.  The Herb Gray Parkway roundabout outside Windsor, Ontario saw 4 trucks rollover from April 2015 to August 2015.  Can you cite a traffic signal that has had 4 truck rollovers in a 5 month period?   You got roughly 300,000 traffic signals in America to choose from.

[jakeroot]

Have there been any rollovers involving single-lane roundabouts? You've mentioned time and time again that single-lane roundabouts are not the problem. Yet, your issue with roundabouts has, lately, been more about the circle itself, and how you have to physically steer around it to avoid crashing (particularly the fact the FHWA indicates that the circle "forces" drivers to slow down). Single-lane roundabouts are just as prone to rollovers as large roundabouts, yet I don't think you've posted about single-lane roundabout rollovers just yet (although this thread is huge, so I may have missed a post).

[kalvado]

Have there been any rollovers involving single-lane roundabouts? You've mentioned time and time again that single-lane roundabouts are not the problem. Yet, your issue with roundabouts has, lately, been more about the circle itself, and how you have to physically steer around it to avoid crashing (particularly the fact the FHWA indicates that the circle "forces" drivers to slow down). Single-lane roundabouts are just as prone to rollovers as large roundabouts, yet I don't think you've posted about single-lane roundabout rollovers just yet (although this thread is huge, so I may have missed a post).

Good question actually. My best guess is that not all intersections are born equal. Intersections of heavier used roads, say arterial grade ones, get much higher share of truck traffic. Trucks are not frequent visitors on residential side streets where single lane roundabout would-be built.
Now if you put a compact single laner on a corner of Warehouse road and Factory drive, where 90% of 2000 daily vehicles are 53 feet long, then that would be a rollover heaven...

[Tarkus]

I know for a fact that there have been rollovers with single-lane roundabouts here in Oregon--particularly the Verboort Road/Martin Road roundabout north of Forest Grove.  I'm trying to find a link to one of the news stories.

[cjw2001]

The simple truth is that drivers do stupid things on all types of roads.   We could just as easily have a thread on "Crash prone modern freeways", "Crash prone modern on ramps", Crash prone modern <fill in the blank".   Or we could just have a thread on "Crash prone impaired drivers".

[jakeroot]

The simple truth is that drivers do stupid things on all types of roads.   We could just as easily have a thread on "Crash prone modern freeways", "Crash prone modern on ramps", Crash prone modern <fill in the blank".   Or we could just have a thread on "Crash prone impaired drivers".

Humans are naturally prone to errors. All infrastructure is capable of producing collisions, but there does seem to be a remarkable uptick in collisions at roundabouts. This seems to be the case due to the, uhh, less-forgiving design of roundabouts. Not seeing a roundabout will almost certainly result in a collision, whereas not seeing a signal has the potential to have no effect (although if there is another car, the collision (a t-bone most likely) could be remarkably worse than simply driving off the road, in the case of a roundabout).

The potential for these catastrophic t-bone collisions seems to be the biggest reason that road agencies prefer roundabouts. However, new data (poorly compiled by Tradephoric -- no offence mate) seems to suggest that the trade-off may not be worth it (which is to say, the number of low-severity collisions skyrockets, whereas severe collisions barely drop off, if at all).

[tradephoric]

This thread has banged on about the crash rates of 2x2 roundabouts, but admittedly it was piecemealed together.  Luckily new research was published in July 2017 that looks at the performance of 2x2 modern roundabouts (entitled Evaluation of Safety and Mobility of Two-Lane Roundabouts).  The research paper concludes what many of us have been saying all along - multilane roundabouts fail to provide a benefit in reducing less severe crashes...

Abstract: When looking at measures of fatal and severe-injury crashes, roundabouts have demonstrated improved safety performance compared to traditional signalized intersections. Despite this, when it comes to less severe crashes, multilane roundabouts fail to provide a similar benefit. Previous research into this topic has identified behaviors that are associated with crashes in two-lane roundabouts, with yielding violations and turn violations generally being the largest contributors to crashes. This study sought to build on that work by expanding the data collection effort to include more sites and relate the frequency of individual behaviors to specific design features. Ultimately, four roundabouts were chosen for data collection and analysis, with two of them being full 2x2 roundabouts and the other two half-2x2. These locations were University Dr. S and 5th Ave. S in St. Cloud (half-2x2), 185th St. W and Kenwood Trail in Lakeville (full-2x2), and TH-22 and Adams St. (half-2x2) and TH-22 and Madison Ave. in Mankato (full-2x2). In the last two, changes in traffic control were implemented to reduce failure-to-yield crashes, and the study compared the driver behavior before and after the interventions. In general, the collective results show that the problems observed in the earlier site are present in all of the other sites with scale variations prompted by geometric and traffic control design elements. For example, in the St. Cloud roundabout, an increased rate of right-from-inner-lane turn violations were observed, which can be attributed to the sharper deflection angles present. Additionally, from the aforementioned roundabout as well as the one in Lakeville, it was concluded that turn violation rates are affected on the single or multilane geometry of the links approaching the roundabout. Single-lane roads result in fewer left-from-outer-lane violations. Overhead lane designation signs result in reduced turn violations similar to the earlier studies' interventions in the approach lane markings. Unfortunately, apart from confirming the trend, no successful design or intervention was discovered regarding yield violations.

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=7&ved=0ahUKEwjAotWnge_VAhVoxoMKHY-sAOsQFghFMAY&url=http%3A%2F%2Fwww.cts.umn.edu%2FPublications%2FResearchReports%2Fpdfdownload.pl%3Fid%3D2818&usg=AFQjCNErF5f42w3IotPdklo9998d9SMgcA

[tradephoric]

A car was cut in half after a driver flew through the middle of a roundabout.  Miraculously everyone survived. 

https://au.news.yahoo.com/video/watch/36726027/out-of-control-car-smashes-through-roundabout/

[tradephoric]

The Mineral Point & Pleasant View roundabout was the most crash prone intersection in Madison in 2016 with 47 crashes.  It has averaged 38.4 crashes per year since it was constructed in 2011.  It has been the most crash prone intersection in the city in 4 of the past 5 years.  Considering the roundabout is surrounded by cornfields, it's somewhat surprising that this is the most crash prone in the city, but then again these 2x2 roundabouts are crash magnets. 

Roundabout on Madison's Far West Side has become a crash magnet
http://host.madison.com/wsj/news/local/roundabout-on-madison-s-far-west-side-has-become-a/article_97b3dd77-a269-5354-8c0a-3f7040cf4373.html

So what is the solution to all these crashes?  City engineer Mark Winter believes drivers are entering the roundabout too fast.  He wants to add more landscaping to the splitter island of the roundabout to restrict the view of drivers approaching the roundabout.  As Winter puts it "if you can see too far to the left when you enter a roundabout, you'll never slow down" .  However, temporary fencing was recently added along the splitter islands of M-5 and Pontiac Trail, a crash prone roundabout in Michigan.  While the fencing did slightly lower the average speed of traffic entering the roundabout, there were just as many crashes in the before and after condition.  A presentation that discussed the M-5/Pontiac Trail fencing was presented at the 5th International Conference on Roundabouts in Green Bay earlier this year. 

There seems to be a level of frustration among roundabout experts regarding these high crash roundabouts.  The realization might be setting in that even a perfectly designed roundabout can fail at reducing crashes.  Here are some of the excerpts from the article...

"Too many drivers still don't know what they are doing in a roundabout,"  Winter said.

"We've given up trying to control the behavior of drivers. It's impossible,"  Winter said.

"It's a tradeoff, like most counter-safety measures,"  Ball said. "I still think there will be fewer crashes. I think there's a lot we're still learning."

Finally the article discusses the findings of a 2013 study done by Ball looking at the safety of roundabouts in Wisconsin.  Of the 30 roundabouts analyzed, 23 saw increases in total crashes (76%).  In addition, the injury crash rate were similar in the before and after condition.  Even while there was a significant increase in total crashes, there was not a significant reduction in injuries.

A study of 30 roundabouts in the state completed by Ball in 2013 that looked at crashes three years before and four years after they opened showed that 23 had more crashes after they opened.

Overall, there were 572 crashes four years after the 30 roundabouts opened versus 311 during the three years before the intersections were converted. Of those, 464 crashes resulting in property damage occurred after the roundabouts opened versus 194 before they opened. Both periods saw similar numbers of accidents with injuries.

But there were no fatalities at the time of the study's release, which was the biggest reason why the roundabouts were built.

[kalvado]

The Mineral Point & Pleasant View roundabout was the most crash prone intersection in Madison in 2016 with 47 crashes.  It has averaged 38.4 crashes per year since it was constructed in 2011.  It has been the most crash prone intersection in the city in 4 of the past 5 years.  Considering the roundabout is surrounded by cornfields, it's somewhat surprising that this is the most crash prone in the city, but then again these 2x2 roundabouts are crash magnets. 

Roundabout on Madison's Far West Side has become a crash magnet
http://host.madison.com/wsj/news/local/roundabout-on-madison-s-far-west-side-has-become-a/article_97b3dd77-a269-5354-8c0a-3f7040cf4373.html

So what is the solution to all these crashes?  City engineer Mark Winter believes drivers are entering the roundabout too fast.  He wants to add more landscaping to the splitter island of the roundabout to restrict the view of drivers approaching the roundabout.  As Winter puts it "if you can see too far to the left when you enter a roundabout, you'll never slow down" .  However, temporary fencing was recently added along the splitter islands of M-5 and Pontiac Trail, a crash prone roundabout in Michigan.  While the fencing did slightly lower the average speed of traffic entering the roundabout, there were just as many crashes in the before and after condition.  A presentation that discussed the M-5/Pontiac Trail fencing was presented at the 5th International Conference on Roundabouts in Green Bay earlier this year. 

There seems to be a level of frustration among roundabout experts regarding these high crash roundabouts.  The realization might be setting in that even a perfectly designed roundabout can fail at reducing crashes.  Here are some of the excerpts from the article...

"Too many drivers still don't know what they are doing in a roundabout,"  Winter said.

"We've given up trying to control the behavior of drivers. It's impossible,"  Winter said.

"It's a tradeoff, like most counter-safety measures,"  Ball said. "I still think there will be fewer crashes. I think there's a lot we're still learning."

Finally the article discusses the findings of a 2013 study done by Ball looking at the safety of roundabouts in Wisconsin.  Of the 30 roundabouts analyzed, 23 saw increases in total crashes (76%).  In addition, the injury crash rate were similar in the before and after condition.  Even while there was a significant increase in total crashes, there was not a significant reduction in injuries.

A study of 30 roundabouts in the state completed by Ball in 2013 that looked at crashes three years before and four years after they opened showed that 23 had more crashes after they opened.

Overall, there were 572 crashes four years after the 30 roundabouts opened versus 311 during the three years before the intersections were converted. Of those, 464 crashes resulting in property damage occurred after the roundabouts opened versus 194 before they opened. Both periods saw similar numbers of accidents with injuries.

But there were no fatalities at the time of the study's release, which was the biggest reason why the roundabouts were built.

My only question is if retirement savings of those experts would be used towards restitution...

[tradephoric]

In other Wisconsin roundabout news, a truck tipped over on a multi-lane roundabout in Eau Claire on US 53 just south of I-94.  The SB lanes of US 53 were shut down for over 3 hours while they cleaned up the mess.

Truck rolls over, spills oil at Eau Claire roundabout
http://www.leadertelegram.com/News/Daily-Updates/2017/08/26/Truck-rolls-over-spills-oil-at-Eau-Claire-roundabout.html