Crash prone 'modern roundabouts'

[tradephoric]

A triple lane roundabout at Northland and Richmond in Appleton is set to open on Friday. 

Appleton's Richmond/Northland intersection to reopen Friday

http://fox11online.com/news/local/appletons-richmond-northland-hwy-oo-roundabout-to-reopen-friday

A previous article indicated that the intersection averaged about 26 crashes/year between 2004 and 2012 (ie. a crash every two weeks).  Now that the roundabout is opening, you are more likely to see a crash every two days. 

Roundabout coming to Richmond and Northland
http://www.postcrescent.com/story/news/local/2014/07/24/roundabout-coming-richmond-northland/13119107/

Between 2004 and 2012, the intersection averaged about a crash every two weeks. About half of those wrecks resulted in an injury, authorities said.

In 2014 Northland and Richmond had 27 crashes, the most in the city.  Does anybody believe a complex triple-lane roundabout will help reduce the number of crashes?  Apparently WisDOT does.

Appleton ranks intersections with most crashes, looks at how to improve them
http://fox11online.com/news/local/fox-cities/appleton-ranks-intersections-with-most-crashes-looks-at-how-to-improve-them

Northland and Richmond was deemed the Appleton intersection with the most crashes in 2014. But the city, county, and state already have a plan in place to address that.

Tim Rank, WisDOT Project Manager, said, "We've got our multi-lane roundabout project planned, construction is planned to start in 2017."

These plans have been in the works since 2009, and now they're close to coming to fruition.

To be exact, 27 crashes happened at that intersection in 2014 alone. The DOT says the new multi-lane roundabout would hopefully reduce that number in the future.

[tradephoric]

Beaufort County City Council members are not big fans of the Bluffton Parkway roundabout.  Significant pavement marking changes were made in 2012 meant to reduce crashes.  There was a short-term reduction in crashes after the pavement changes but it didn't last.  There are now talks to eliminate the outside lane of the multi-lane roundabout and force the right-hand lane to go right at all entry points or to eliminate the roundabout altogether and replace it with a traffic signal.

Hate the Bluffton Parkway traffic circle? Join the club. But how could it change?
http://www.islandpacket.com/news/local/traffic/article170040982.html

"The number of phone calls (from local drivers), the number of visits, the number of emails – this subject has been unending,"  Beaufort County Councilman Mike Covert said.

Councilman Jerry Stewart said, "From what I hear, a lot of people won't drive there because they don't want to negotiate"  the circle.

Councilman Tabor Vaux said he supports an idea to eliminate the outside lane of the roundabout and force the right-hand lane to go right at all entry points, similar to the Sea Pines Circle on Hilton Head Island.  "I think that's what needs to happen there,"  he said. "What do we need to make that happen?"  Vaux asked county engineering staff. "I came very, very close to getting in a wreck there (earlier this week) – I know of six or seven people who have gotten in wrecks there recently."

Stewart agreed, saying, "You really have to very careful or you're going to be hit. Something has to be done,"  he said. "... It was poorly designed – period."

[tradephoric]

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).

Single-lane roundabouts haven't been a problem in respect to high crash rates, but they are prone to truck tip overs.  Over the weekend a fuel tanker flipped on its side at a single-lane roundabout at St. John's International Airport.  The roundabout was shut down for 8 hours as hazmat crews cleaned up the accident and offloaded the fuel from the tanker onto another truck.  Worst yet, the airlines experienced a fuel shortage at the airport and a Boeing 747 took off with a low fuel load.  Due to a diversion mid-flight, the plane ran out of fuel and crashed into a cornfield in Kansas killing all 269 people on board.   The last part of the story may not have happened, but even if it had the roundabout would be touted for its safety record.

Having a truck tip over and shutting down a roundabout for a good part of the day is not desirable (not to mention the danger to truck drivers when their 20 ton load flips over).  Hopefully not too many people in St. John's missed their flight over the weekend.

Fuel tanker overturns in St. John's airport roundabout -
Tanker driver taken to hospital with non-life threatening injuries
http://www.cbc.ca/news/canada/newfoundland-labrador/fuel-tanker-overturns-in-roundabout-at-st-john-s-airport-roundabout-1.4273758

[jeffandnicole]

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).

Single-lane roundabouts haven’t been a problem in respect to high crash rates, but they are prone to truck tip overs.  Over the weekend a fuel tanker flipped on its side at a single-lane roundabout at St. John’s International Airport.  The roundabout was shut down for 8 hours as hazmat crews cleaned up the accident and offloaded the fuel from the tanker onto another truck.  Worst yet, the airlines experienced a fuel shortage at the airport and a Boeing 747 took off with a low fuel load.  Due to a diversion mid-flight, the plane ran out of fuel and crashed into a cornfield in Kansas killing all 269 people on board.   The last part of the story may not have happened, but even if it had the roundabout would be touted for its safety record.

Having a truck tip over and shutting down a roundabout for a good part of the day is not desirable (not to mention the danger to truck drivers when their 20 ton load flips over).  Hopefully not too many people in St. John's missed their flight over the weekend.

Fuel tanker overturns in St. John's airport roundabout -
Tanker driver taken to hospital with non-life threatening injuries
http://www.cbc.ca/news/canada/newfoundland-labrador/fuel-tanker-overturns-in-roundabout-at-st-john-s-airport-roundabout-1.4273758

Being that traffic had to detour a whole 1/4 mile to the next intersection, I think people managed to deal with the situation just fine.

[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.

Jeffandnicole you never got back to me.  Did you ever find a signalized intersection that has had 4 truck rollovers in a 5 month period?  That's what happened at the Herb Gray Parkway roundabout. Depending what direction on the 401 you are traveling, traffic is diverted over 6 miles if that roundabout is closed (which it is frequently due to the absurd number of trucks flipping over on it).  Maybe a ¼ mile is no big deal, but what about 6 miles?  Wouldn't you find that annoying?  You seem to give roundabouts the benefit of the doubt, so I take it you wouldn't mind driving 6 miles out of your way.

[jeffandnicole]

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.

Jeffandnicole you never got back to me.  Did you ever find a signalized intersection that has had 4 truck rollovers in a 5 month period?  That’s what happened at the Herb Gray Parkway roundabout. Depending what direction on the 401 you are traveling, traffic is diverted over 6 miles if that roundabout is closed (which it is frequently due to the absurd number of trucks flipping over on it).  Maybe a ¼ mile is no big deal, but what about 6 miles?  Wouldn’t you find that annoying?  You seem to give roundabouts the benefit of the doubt, so I take it you wouldn’t mind driving 6 miles out of your way.

I don't spend every waking moment Googling accidents at specific intersections for the sole purpose of posting on this forum, so no, I didn't find any.

[tradephoric]

There are so many problematic roundabouts that have a history of tip-overs it takes hardly any time at all compiling the data.  Instead of spending 5 minutes highlighting traffic signals that are prone to truck tip-overs, you spend your time researching NJ Turnpike accidents and then post them on a forum about roundabouts.  Stay classy NJ.  So how is that petition to ban highway on-ramps going?

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

[kalvado]

There are so many problematic roundabouts that have a history of tip-overs it takes hardly any time at all compiling the data.  Instead of spending 5 minutes highlighting traffic signals that are prone to truck tip-overs, you spend your time researching NJ Turnpike accidents and then post them on a forum about roundabouts.  Stay classy NJ.  So how is that petition to ban highway on-ramps going?

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

As far as I remember, there are 2 people loosing life on roads every hour. We need to ban roads!

On a more serious note, problems are associated with any single human action; and it is about cost-benefit analysis to determine if solution worth the trouble, or it creates more problems than is solves.
It is pretty obvious that roundabouts are designed so that they become prone to tipping over. You only need to know high school physics to tell that. Now if that is an acceptable problem because it is fairly uncommon, or it is a systematic problem which needs to be addressed is another issue.
Tipping over on a ramp seems way less common, and given mere amount of ramps compared to roundabout - i wonder if there would be a single truck left on the road if probabilities were the same...

[johndoe]

TRB has an upcoming webinar that may interest some of you: http://www.trb.org/Calendar/Blurbs/176470.aspx

[kalvado]

TRB has an upcoming webinar that may interest some of you: http://www.trb.org/Calendar/Blurbs/176470.aspx

Just $105? Sorry, I don't have any spare change with me..

[tradephoric]

TRB has an upcoming webinar that may interest some of you: http://www.trb.org/Calendar/Blurbs/176470.aspx

John Hourdos is going to be moderating this webinar.  In a previous webinar he had discussed crash prone multi-lane roundabouts in Richfield, MN and his research was going to be expanded to additional multi-lane roundabouts in Minnesota (University Dr & 5th Ave in St. Cloud; Hwy 22 at Adams St and Madison Ave in Mankato; 50/60 Roundabout in Lakeville).  A research paper was published in July 2017 that discusses the results of this additional research and I'm sure the upcoming webinar will touch on a lot of it.  The paper concluded that no successful design or intervention was discovered that lowered yield violations (which is a big percentage of the crashes that occur at these complex roundabouts).

Evaluation of Safety and Mobility of Two-Lane Roundabouts
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

It looks like Mark McCulloch from Washtenaw Road Commission will also be presenting in the webinar.  He is the man behind the notorious State and Ellsworth roundabout.  Before the roundabout was built, Mark was cocky and thought the roundabout was going to work great (he admitted so much at the roundabout conference this year).  But after countless crashes, reality has set in for him.  And until he can cite concrete evidence that the roundabout has reduced injury crashes at the intersection, he's delusional for thinking that the roundabout is safer. 

[tradephoric]

Probability and statistics question:

The City of Madison has about 200 traffic signals and 7 roundabouts.  Assuming that traffic signals and roundabouts have the same crash rate, what is the probability that the top 3 most crash prone intersections in the city are all roundabouts? 

City of Madison, WI 2016 Crash Report
https://www.cityofmadison.com/trafficEngineering/documents/2016CrashReport.pdf

[jakeroot]

It looks like Mark McCulloch from Washtenaw Road Commission will also be presenting in the webinar.  He is the man behind the notorious State and Ellsworth roundabout.  Before the roundabout was built, Mark was cocky and thought the roundabout was going to work great (he admitted so much at the roundabout conference this year).  But after countless crashes, reality has set in for him.  And until he can cite concrete evidence that the roundabout has reduced injury crashes at the intersection, he's delusional for thinking that the roundabout is safer.

He wasn't cocky. There wasn't much of any "concrete evidence" that multi-lane roundabouts weren't an effective solution to curbing collisions and reducing severity back when they built the roundabout. A lot of the data that you cite comes from the last three to four years.

[jakeroot]

Probability and statistics question:

The City of Madison has about 200 traffic signals and 7 roundabouts.  Assuming that traffic signals and roundabouts have the same crash rate, what is the probability that the top 3 most crash prone intersections in the city are all roundabouts?

It's a 207-way tie.

EDIT: Or, is that not what you are getting at?

[kalvado]

Probability and statistics question:

The City of Madison has about 200 traffic signals and 7 roundabouts.  Assuming that traffic signals and roundabouts have the same crash rate, what is the probability that the top 3 most crash prone intersections in the city are all roundabouts? 

City of Madison, WI 2016 Crash Report
https://www.cityofmadison.com/trafficEngineering/documents/2016CrashReport.pdf

Incomplete problem definition.
If roundabouts were built to replace most problematic  - highest volume, or otherwise difficult - light control intersections, pure arithmetic probability is not 100% relevant.

[tradephoric]

There are 200 red marbles and 7 blue marbles mixed up in a bag.  What is the probability that the first 3 marbles pulled out of the bag are blue. 

[tradephoric]

Driver fatally injured after striking a 4-ton boulder in the middle of a Prescott roundabout.  Another fixed object fatality in the middle of a roundabout.

37-Year-Old Man from Page Dies in Crash at Roundabout
http://www.prescottenews.com/index.php/news/current-news/item/30613-37-year-old-man-from-page-dies-in-crash-at-roundabout

[kalvado]

There are 200 red marbles and 7 blue marbles mixed up in a bag.  What is the probability that the first 3 marbles pulled out of the bag are blue.

What is the probability I would see a mastodon on my way home?
I would say 50% - either  "yes" or "no"!

[jeffandnicole]

There are 200 red marbles and 7 blue marbles mixed up in a bag.  What is the probability that the first 3 marbles pulled out of the bag are blue. 

1 in 41,627.

Do you want me to show my work?

[jakeroot]

There are 200 red marbles and 7 blue marbles mixed up in a bag.  What is the probability that the first 3 marbles pulled out of the bag are blue. 

1 in 41,627.

Do you want me to show my work?

7/207 x 6/206 x 5/205

Still not sure what he wants us to get out of this.

[tradephoric]

There are 200 red marbles and 7 blue marbles mixed up in a bag.  What is the probability that the first 3 marbles pulled out of the bag are blue. 

1 in 41,627.

Do you want me to show my work?

Nope that is the answer I got!  Now replace red marbles with traffic signals and blue marbles with roundabouts and it highlights the unlikelihood that Madison's top 3 crash locations would all be at roundabouts.  To put 1 in 41,627 into perspective... the odds of getting struck by lightning in your lifetime is 1 in 3,000.

And the crashes aren't even close.  The Mineral Point & Pleasant View roundabout experienced 47 crashes compared to just 16 crashes at the Darwin Rd & Packers Ave traffic signal (the most crash prone traffic signal in the city).  And as mentioned the Mineral Point & Pleasant View roundabout is surrounded by cornfields... not a location you would expect to see the most number of crashes in the city.

[kalvado]

There are 200 red marbles and 7 blue marbles mixed up in a bag.  What is the probability that the first 3 marbles pulled out of the bag are blue. 

1 in 41,627.

Do you want me to show my work?

Nope that is the answer I got!  Now replace red marbles with traffic signals and blue marbles with roundabouts and it highlights the unlikelihood that Madison's top 3 crash locations would all be at roundabouts.  To put 1 in 41,627 into perspective... the odds of getting struck by lightning in your lifetime is 1 in 3,000.

And the crashes aren't even close.  The Mineral Point & Pleasant View roundabout experienced 47 crashes compared to just 16 crashes at the Darwin Rd & Packers Ave traffic signal (the most crash prone traffic signal in the city).  And as mentioned the Mineral Point & Pleasant View roundabout is surrounded by cornfields... not a location you would expect to see the most number of crashes in the city.

Common mistake for freshmen probability course.
What you're saying would be correct if roundabouts were randomly distributed around the city ("marbles" are all equal).
WIth all my disrespect to those designing roundabouts, I still doubt they choose locations by flipping a coin. Most likely intersections with pre-existing problem are addressed. So roundabout locations were not just simple regular marbles to begin with

[jakeroot]

[T]he Mineral Point & Pleasant View roundabout is surrounded by cornfields... not a location you would expect to see the most number of crashes in the city.

Not necessarily. We've discussed, in the past, about visibility at (and approaching) roundabouts. If visibility is too good, drivers might* be more likely to determine whether or not they can "make it" through without crashing from a longer way's away. It's possible that some of these crashes are due to poor judgement in that respect.

It's also possible that the rural location has high-speed approaches, contributing to run-off, "I didn't see it coming" collisions. The kind where the car goes over the roundabout, or fails to yield due to high speed + not enough braking time to properly yield.

*emphasis on "might" because past studies on visibility have been inconclusive (IIRC).

[tradephoric]

The City of Hilliard Division of Engineering is studying three crash prone roundabouts in Hilliard.  They put together an informative website detailing the problems and possible counter-measures they are considering at the roundabouts.  According to the city, there have been 231 crashes at the Cemetery Rd & Main St roundabout from 2014-2016 (10% resulting in injury).

http://www.hilliardohio.gov/roundabouts/study



   

[Scott5114]

The last time I went through a roundabout, it ran out of memory and froze up until the DOT came by and rebooted it.