Crash prone 'modern roundabouts'

[kphoger]

Does that take away from the fact there are complex roundabouts being built to this day with very high crash rates?  The roundabout in Fishers being the latest example.  As long as engineers continue to design these complex roundabouts that experience triple-digit crashes per year, I'll continue to mention them. 

Has the Fishers roundabout (at 96th & Allisonville, opened in October) had triple-digit crashes per year?

[tradephoric]

Has the Fishers roundabout (at 96th & Allisonville, opened in October) had triple-digit crashes per year?

According to Fisher's Police there were 29 crashes at the 96th / Allisonville roundabout between October 29-December 11, 2024.  At that pace (0.65 crashes per day) the roundabout would average 240 crashes per year.  Unfortunately that's the latest crash data i have seen.  There was another documented crash involving a red Toyota RAV‑4 that flipped onto its side, shattering its windows on the evening of January 27th, 2025 (highlighted in article below):

Fishers considers delaying construction of roundabout at 116th and Allisonville
https://www.newsbreak.com/news/3792106435712-fishers-considers-delaying-construction-of-roundabout-at-116th-and-allisonville

The roundabout will see over 100 crashes in the first year of operations.  I'll give you 5 to 1 odds if you want to take the under.  Let me know if you want to take the bet.

[kphoger]

According to Fisher's Police there were 29 crashes at the 96th / Allisonville roundabout between October 29-December 11, 2024.  At that pace (0.65 crashes per day) the roundabout would average 240 crashes per year.  Unfortunately that's the latest crash data i have seen. ... I'll give you 5 to 1 odds if you want to take the under.  Let me know if you want to take the bet.

No, that's fine.  Thank you for providing the numbers.  But you didn't do that at first.  All you'd done was claim that the roundabout was an example of "the latest example" of "these complex roundabouts that experience triple-digit crashes per year" with no data to back up the claim.  Forgive me for having become skeptical and jaded.

[tradephoric]

According to Fisher's Police there were 29 crashes at the 96th / Allisonville roundabout between October 29-December 11, 2024.  At that pace (0.65 crashes per day) the roundabout would average 240 crashes per year.  Unfortunately that's the latest crash data i have seen. ... I'll give you 5 to 1 odds if you want to take the under.  Let me know if you want to take the bet.

No, that's fine.  Thank you for providing the numbers.  But you didn't do that at first.  All you'd done was claim that the roundabout was an example of "the latest example" of "these complex roundabouts that experience triple-digit crashes per year" with no data to back up the claim.  Forgive me for having become skeptical and jaded.

Not a problem, i just had already cited that crash data previously on here.  There's really no reason to be skeptical or jaded as I'm pretty open with whatever data i have.

Drove through the 96th and Allisonville roundabout at noon today and traffic was flowing smoothly.  Looks like Fishers added the "to Both Lanes" under all the Yield signs within the last few days.

Did the original design call for the "to both lanes" signs be installed under the yield signs?  If not, that could indicate the city is already seeing a crash problem at the roundabout and are already tweaking with the signage. 

According to Fisher's Police there were 29 crashes at the new roundabout between October 29-December 11, 2024 compared to 7 crashes between October 29-December 11, 2023.  At that pace (0.65 crashes per day) the roundabout would average 240 crashes per year.  Not saying it ends up with 240 crashes per year, but the first 44 days of crash data at the new roundabout doesn't exudes confidence. 

[kphoger]

Not a problem, i just had already cited that crash data previously on here.

Ah, I hadn't scrolled back far enough.

There's really no reason to be skeptical or jaded as I'm pretty open with whatever data i have.

There is, as long as you post news stories about lone incidents with no context to justify their location being called 'crash-prone'.

[tradephoric]

Accident With Injuries at Roundabout in Hershey

At least one person was taken to the hospital following a crash at the roundabout at Route 322 and Meadow Lane in Hershey on Thursday morning, Feb. 20. Crews were dispatched to the scene shortly after 11 a.m. after a vehicle crashed into the wall in the center of the roundabout. First responders extricated one person, who was taken to the hospital for their injuries, which are believed to be non-life threatening. Photo: Drew Weidman.
https://news.thesunontheweb.com/articles/accident-with-injuries-at-roundabout-in-hershey/

The speed limit is 50mph along WB Route 322 as you are approaching the roundabout.  There's a brick retaining wall in the central island and any driver that continues straight who is unable to successfully navigate the roundabout risks injury or death.  Why put retaining walls in central islands, especially along roadways with 30mph+ speed limits.

[kphoger]

The speed limit is 50mph along WB Route 322 as you are approaching the roundabout.  There's a brick retaining wall in the central island and any driver that continues straight who is unable to successfully navigate the roundabout risks injury or death.  Why put retaining walls in central islands, especially along roadways with 30mph+ speed limits.

Granted, this publication is from the year 2000, so the FHWA may have updated its guidance since then.  But, interestingly, they actually recommended landscaping in the central island, and they only discouraged large fixed objects in "areas vulnerable to vehicle runoff".

While this particular roundabout is not oval-shaped (as discussed in 6.3.4 of the same publication), you'd think that a higher speed limit would be considered as a contributing factor to its vulnerability to vehicle runoff, wouldn't you?

Roundabouts:  An Informational Guide
Publication No. FHWA-RD-00-067
Chapter 7 — Traffic Design and Landscaping
7.5.2 — Landscaping — Central Island Landscaping

The central island landscaping can enhance the safety of the intersection by making the intersection a focal point and by lowering speeds. Plant material should be selected so that sight distance (discussed in Chapter 6) is maintained, including consideration of future maintenance requirements to ensure adequate sight distance for the life of the project. Large, fixed landscaping (trees, rocks, etc.) should be avoided in areas vulnerable to vehicle runoff.

[tradephoric]

Here's a list of the 38 deadliest intersections in America that had 5 or more fatal crashes from 2004 through 2021 (the latest year they had data for):

https://www.piastawalker.com/2024/02/16/analysis-the-deadliest-intersections-in-america/

The roundabout at US95A and US-50 in Lyon County, Nevada opened in May, 2020 and has already had 3 known fatal crashes.  It's currently averaging 0.63 fatal crashes per year (3 fatal crashes in 4.75 years of operation) which is higher than the 0.44 fatal crashes (8 fatal crashes in 18 years) at the US-98 and Carl Hudson Road intersection.  While not a complete apples-to-apples comparison considering the roundabout is so new and there's simply not 18 years of crash data to analyze, it's becoming obvious that the US95A and US-50 roundabout is one of the deadliest roundabouts in America if not one of the deadliest intersections in all of America.  Having 3 fatal crashes over any 5 year period is a really bad result.  All of the fatal crashes involve vehicles striking these "decorative rocks".

Silver Springs man identified in fatal crash on US-50 in Lyon County
https://www.carsonnow.org/05/29/2024/silver-springs-man-identified-fatal-crash-us-50-lyon-county

Fallon Man Dies in Crash Near U.S. 50 Roundabout in Silver Springs
https://www.2news.com/fallon-man-dies-in-crash-near-u-s-50-roundabout-in-silver-springs/article_5bcf26bc-a38c-598c-beed-40bde873699b.html

NHP: Mechanical failure to blame for fiery Silver Springs crash
https://www.kolotv.com/2021/05/29/fiery-silver-springs-crash-was-fatal/

[tradephoric]

It can't help that the roundabout is at the bottom of a 6% grade when traveling SB US-50 Alternative.  If the trucker can't stop going down the steep grade, is the intersection now a roundabout or a rock death trap? 

NHP said the driver of a tractor-trailer was going south on U.S. 50 Alternate. As he approached the roundabout, he was unable to slow his rig due to a suspected mechanical issue and crashed into the back of a Honda, which was in front of him going the same direction.

The impact pushed both vehicles into the raised decorative rock median and both the tractor-trailer and the car caught fire.
https://www.kolotv.com/2021/05/29/fiery-silver-springs-crash-was-fatal/

[pderocco]

The roundabout at US95A and US-50 in Lyon County, Nevada opened in May, 2020 and has already had 3 known fatal crashes.  It's currently averaging 0.63 fatal crashes per year (3 fatal crashes in 4.75 years of operation) which is higher than the 0.44 fatal crashes (8 fatal crashes in 18 years) at the US-98 and Carl Hudson Road intersection.  While not a complete apples-to-apples comparison considering the roundabout is so new and there's simply not 18 years of crash data to analyze, it's becoming obvious that the US95A and US-50 roundabout is one of the deadliest roundabouts in America if not one of the deadliest intersections in all of America.  Having 3 fatal crashes over any 5 year period is a really bad result.  All of the fatal crashes involve vehicles striking these "decorative rocks".

That looks easy to fix. Get rid of the rocks.

[kphoger]

It can't help that the roundabout is at the bottom of a 6% grade when traveling SB US-50 Alternative.  If the trucker can't stop going down the steep grade, is the intersection now a roundabout or a rock death trap?

I'm pretty sure I've mentioned this before, but that's why the city of Branson (MO) took over part of US-65-Business.  While it was still a bannered US Route, they weren't allowed to build a roundabout at Skaggs Road because of the steep grade coming down from the north.  The city's solution, rather than choose a different type of intersection, was to make it a local street exempt from the restriction.

[Scott5114]

I guess the real question is how often accidents happen at the circle in Lebanon TN.

It no longer matters.  This is now the "Anytime there's a crash at any roundabout anywhere for any reason" thread.  He doesn't care if it's actually crash-prone or not.

This thread was never about crash-prone roundabouts—not one of the roundabouts in this thread have ever crashed into something else.

[tradephoric]

That looks easy to fix. Get rid of the rocks.

At its current pace of 0.6 fatal crashes per year, there would be 9 fatal crashes at the US-50 & US-95A roundabout by 2035.  That would make it one of the deadliest, if not the deadliest intersection in America.  How long are they going to wait to remove those rocks?

[Scott5114]

That looks easy to fix. Get rid of the rocks.

At its current pace of 0.6 fatal crashes per year, there would be 9 fatal crashes at the US-50 & US-95A roundabout by 2035.  That would make it one of the deadliest, if not the deadliest intersection in America.  How long are they going to wait to remove those rocks?

If they want to crash into rocks that badly, that's their God-given right as a Nevadan, and who is NDOT to deny them that?

[Rothman]

That looks easy to fix. Get rid of the rocks.

At its current pace of 0.6 fatal crashes per year, there would be 9 fatal crashes at the US-50 & US-95A roundabout by 2035.  That would make it one of the deadliest, if not the deadliest intersection in America.  How long are they going to wait to remove those rocks?

If they want to crash into rocks that badly, that's their God-given right as a Nevadan, and who is NDOT to deny them that?

Three accidents spread over 2021, 2022 and 2024 is a pace of sorts, I suppose.

[jakeroot]

That looks easy to fix. Get rid of the rocks.

Here's a little devils advocacy for you: without the rocks, they might have passed over the middle of the roundabout and T-boned a car circulating on the far side, potentially killing other innocent drivers.

You'd be surprised how many people are for capital punishment when it involves a driver making a dumb decision. I'm of the opinion that we should do as little as possible to kill drivers, even those that mistakes. But, the only thing worse than a driver being killed is them taking other innocent people with them.

At the end of the day, there should not be anything in the middle of a roundabout that could kill someone. I'd rather take the chance of them passing over the middle and slowly coming to a rest than guaranteeing their death if they don't see the roundabout coming, as is the case with the rocks at this current roundabout.

[kalvado]

That looks easy to fix. Get rid of the rocks.

At its current pace of 0.6 fatal crashes per year, there would be 9 fatal crashes at the US-50 & US-95A roundabout by 2035.  That would make it one of the deadliest, if not the deadliest intersection in America.  How long are they going to wait to remove those rocks?

If they want to crash into rocks that badly, that's their God-given right as a Nevadan, and who is NDOT to deny them that?

Some DOT employees pretend to be engineers...

[pderocco]

That looks easy to fix. Get rid of the rocks.

Here's a little devils advocacy for you: without the rocks, they might have passed over the middle of the roundabout and T-boned a car circulating on the far side, potentially killing other innocent drivers.

Try gravel, like runaway truck ramps. Or perhaps sand.

[Rothman]

That looks easy to fix. Get rid of the rocks.

At its current pace of 0.6 fatal crashes per year, there would be 9 fatal crashes at the US-50 & US-95A roundabout by 2035.  That would make it one of the deadliest, if not the deadliest intersection in America.  How long are they going to wait to remove those rocks?

If they want to crash into rocks that badly, that's their God-given right as a Nevadan, and who is NDOT to deny them that?

Some DOT employees pretend to be engineers...

Given PEs need licenses, that's an interesting statement.

[kalvado]

That looks easy to fix. Get rid of the rocks.

At its current pace of 0.6 fatal crashes per year, there would be 9 fatal crashes at the US-50 & US-95A roundabout by 2035.  That would make it one of the deadliest, if not the deadliest intersection in America.  How long are they going to wait to remove those rocks?

If they want to crash into rocks that badly, that's their God-given right as a Nevadan, and who is NDOT to deny them that?

Some DOT employees pretend to be engineers...

Given PEs need licenses, that's an interesting statement.

A favorite topic of many discussions - what's the percentage of those who have driver license actually knows how to drive?

[tradephoric]

Fishers Police reported 63 crashes at the 96th Street/Allisonville roundabout from Nov. 1, 2024 to February 1, 2025 (92 days).  This compares to 10 crashes during the same time-period the year before when the intersection was still a Michigan Left.  There was a modest 1.7% YoY increase in traffic volumes according to INDOT traffic counts (57k in 2023, 58k in 2024). 



The 96th Street/Allisonville roundabout was supposed to ease traffic. Instead crashes soared
https://www.indystar.com/story/news/local/hamilton-county/fishers/2025/03/12/crashes-allisonville-road-96th-street-roundabout-ifishers/78990925007/

[kphoger]

Fishers Police reported 63 crashes at the 96th Street/Allisonville roundabout from Nov. 1, 2024 to February 1, 2025 (92 days).  This compares to 10 crashes during the same time-period the year before when the intersection was still a Michigan Left.  There was a modest 1.7% YoY increase in traffic volumes according to INDOT traffic counts (57k in 2023, 58k in 2024).

Farther down the article:

Mekky said almost every accident has been caused by drivers failing to yield at the entrance to the roundabout or switching lanes illegally once they're in it.

[...]

But some drivers have said that the intersection seems too small, with not enough decision time before they need to enter.

[...]

Peter T. Savolainen, a professor of engineering at Michigan State University, said the number of motorists going through the 96th Street intersection was already close to the recommended maximum before potential diverted traffic came along.

"That is a very large traffic volume for a roundabout," Savolainen said. "We completed a Michigan DOT study and there were only a few sites anywhere near that volume range. This is approaching or exceeding the upper boundary (in terms of annual average daily traffic, AADT) for a two-lane roundabout."

It also suggests that the skewed geometry may be a factor, but that there is very little research about non-90° roundabouts to see if they have a higher crash rate as do do non-90° traditional intersections.

[tradephoric]

I think you are asking for trouble when you plop a roundabout at an intersection with over 50k AADT.  It's 50k drivers a day judging gaps in traffic and playing a real world game of Frogger.

The non-90 degree angles at the roundabout would be interesting to research, but ultimately the higher traffic volumes seems to be the underlying problem.  Can we even find a single roundabout in America with over 50k AADT that has performed well.. averaging under 50 crashes per year would be a success at this point.

[kalvado]

I think you are asking for trouble when you plop a roundabout at an intersection with over 50k AADT.  It's 50k drivers a day judging gaps in traffic and playing a real world game of Frogger.

The non-90 degree angles at the roundabout would be interesting to research, but ultimately the higher traffic volumes seems to be the underlying problem.  Can we even find a single roundabout in America with over 50k AADT that has performed well.. averaging under 50 crashes per year would be a success at this point.

If I remember correctly, throughput  depends on traffic pattern, mostly on %% of left turning traffic - but 30k is about maximum reported in research papers. FHWA optimistically says "up to 50k when everyone goes straight, no turns" (exhibit 3.1, Publication No.FHWA-RD-00-067), but when did the stupid science limited the might of The Federal Government of The United States of America??
_{Elon, please take a notice!}

[CoreySamson]

I think it says a lot about how poorly designed that Fishers roundabout is in that there are driver complaints and that there are no less than 10 roundabouts along that same road. You can't just chalk that one up to driver unfamiliarity with roundabouts.