Crash prone 'modern roundabouts'

[jeffandnicole]

More like a smaller municipality news outlet is not flooded by other news and provides a clear view of disastrous design.

In my local paper, they would print about one accident a day somewhere in the county, usually something real minor.  You know, to make it 'local'.  A crash that takes down a traffic light?  Eh, maybe it gets mentioned.  A crash on the highway shutting it down causing thousands of people to congest all the side streets, delaying everyone for an hour?  You'll never read about it.  So, it's a little funny what newspapers decide to print on.  Something that affected thousands is overlooked; something that 10 people saw as they passed by gets mentioned in the paper.

The paper did write this story one time:  A young 20-something year old was in an accident and arrested for DUI.  She wrote the reporter most likely to write something about it, begging him not to write anything so she wouldn't be embarrassed for family reasons, had a new job, etc.  So the reporter wrote a column about this request.  He looked up the accident, and admitted that even though it involved an arrest for DUI, it was otherwise a very run-of-the-mill incident that he otherwise wouldn't have even taken a second glance at.  The reporter was nice though and never mentioned the name of the person or where the incident occurred.

[kalvado]

More like a smaller municipality news outlet is not flooded by other news and provides a clear view of disastrous design.

In my local paper, they would print about one accident a day somewhere in the county, usually something real minor.  You know, to make it 'local'.  A crash that takes down a traffic light?  Eh, maybe it gets mentioned.  A crash on the highway shutting it down causing thousands of people to congest all the side streets, delaying everyone for an hour?  You'll never read about it.  So, it's a little funny what newspapers decide to print on.  Something that affected thousands is overlooked; something that 10 people saw as they passed by gets mentioned in the paper.

The paper did write this story one time:  A young 20-something year old was in an accident and arrested for DUI.  She wrote the reporter most likely to write something about it, begging him not to write anything so she wouldn't be embarrassed for family reasons, had a new job, etc.  So the reporter wrote a column about this request.  He looked up the accident, and admitted that even though it involved an arrest for DUI, it was otherwise a very run-of-the-mill incident that he otherwise wouldn't have even taken a second glance at.  The reporter was nice though and never mentioned the name of the person or where the incident occurred.

I wouldn't be surprised if DWI reports are viewed as a way to keep people aware of the issue and send "you will be caught, and it will be nasty" message. Makes at least some sense...
An accident that backed up highway in NJ must be a daily thing, and there is a traffic report section for that

[Rothman]

Difficulty in acquiring the actual data does not legitimize conclusions drawn from anecdotal or incomplete data.  If you want your research to be taken seriously, do what real researchers do and jump through the hoops to get real data.

[kalvado]

Difficulty in acquiring the actual data does not legitimize conclusions drawn from anecdotal or incomplete data.  If you want your research to be taken seriously, do what real researchers do and jump through the hoops to get real data.

At least our truck rollovers in a same location within less than a year is NOT anecdotal data, it is clearly poor design. 
You cannot give exact numbers from this dataset - but you must admit that is is way above any expected number. In such a case case you don't need more data, you need to fire people and bulldoze the structure and work out details as reckless endagerment case is filed in a court.
I am a bit exaggerating - not too much, though. But you don't need to be a chef to tell that the steak on your plate is made from rotten meat. Nor you need bacterial DNA analysis before throwing it away.

[tradephoric]

According to the article linked below, the 3 most crash prone intersections in Carmel are all at roundabouts along 116th Street.  Based on the data taken directly from the article I calculated the crash rates at each roundabout:



The average crash rate at signalized intersections is about 0.8 crashes per MEV.  The crash rate of these Carmel roundabouts are 6 to 20 times higher than the average crash rate of a standard signalized intersection.  This fact doesn't prevent the Carmel Police Department from trying to attribute the high number of accidents at these roundabouts to the high volume of traffic going through them. 

Top 4 intersections for accidents all in Hamilton County
https://www.wishtv.com/news/i-team-8/top-four-intersections-for-accidents-all-in-hamilton-county/1273973180

[jeffandnicole]

I wouldn't be surprised if DWI reports are viewed as a way to keep people aware of the issue and send "you will be caught, and it will be nasty" message. Makes at least some sense...
An accident that backed up highway in NJ must be a daily thing, and there is a traffic report section for that

It's more like an hourly thing.  It's just expected.   They're rarely reported on.

[kalvado]

I wouldn't be surprised if DWI reports are viewed as a way to keep people aware of the issue and send "you will be caught, and it will be nasty" message. Makes at least some sense...
An accident that backed up highway in NJ must be a daily thing, and there is a traffic report section for that

It's more like an hourly thing.  It's just expected.   They're rarely reported on.

What I am saying is more that it may be a good idea to report a DWI in the news once in a while - preferably ones where driver faces something really nasty. You know, just to keep kids aware that it's not worth it.  Not necessarily all of those, just to keep issue on the radar.
Can be used to fill gaps on a slow day, and hopefully may be coming with return of investment via DWI rate reduction.
Same for cell phone distracted driving accident, possibly.
But overscaring the public is not worth it, so serious accidents without underlying hot issues... FOIL police reports if desired, or leave it to professionals 

[jeffandnicole]

I wouldn't be surprised if DWI reports are viewed as a way to keep people aware of the issue and send "you will be caught, and it will be nasty" message. Makes at least some sense...
An accident that backed up highway in NJ must be a daily thing, and there is a traffic report section for that

It's more like an hourly thing.  It's just expected.   They're rarely reported on.

What I am saying is more that it may be a good idea to report a DWI in the news once in a while - preferably ones where driver faces something really nasty. You know, just to keep kids aware that it's not worth it.  Not necessarily all of those, just to keep issue on the radar.
Can be used to fill gaps on a slow day, and hopefully may be coming with return of investment via DWI rate reduction.
Same for cell phone distracted driving accident, possibly.
But overscaring the public is not worth it, so serious accidents without underlying hot issues... FOIL police reports if desired, or leave it to professionals 

Ah!  Yeah, they're definitely reported on, especially those that cause injury or death. 

[Mr. Matté]

I wonder how crash-prone this roundabout is.

https://twitter.com/Streetfilms/status/1023739247826632705

Can we find any pedestrian-only roundabouts?

Of course New Jersey would have a bike lane with a jughandle:

[plain]

Of course New Jersey would have a bike lane with a jughandle:

That's the New Jerseyest thing I've seen yet.

[jeffandnicole]

Of course New Jersey would have a bike lane with a jughandle:

That's the New Jerseyest thing I've seen yet.

That. Is. Awesome.

Where is this?

[tradephoric]

^Only in New Jersey!  While we are on the topic of oddities, are these roundabout guide markings found in the MUTCD anywhere?


https://www.google.com/maps/@41.3343067,-75.7346423,80m/data=!3m1!1e3

[tradephoric]

A "divergabout" opened in Lee's Summit, MO in May of this year.  It combines the complexities of a dual lane-roundabout with that of DDI.  Whoever designed this interchanges must hate me 
https://www.youtube.com/watch?v=zH5EfvCdPQQ
https://www.youtube.com/watch?v=Xd4-gt9VBeI

[jakeroot]

While we are on the topic of oddities, are these roundabout guide markings found in the MUTCD anywhere?

https://i.imgur.com/qeGjQ4j.jpg
https://www.google.com/maps/@41.3343067,-75.7346423,80m/data=!3m1!1e3

I have only seen them one time, and that was the Pat Bay Hwy @ McTavish Road near Sidney, BC, also a roundabout interchange:

A "divergabout" opened in Lee's Summit, MO in May of this year.  It combines the complexities of a dual lane-roundabout with that of DDI.  Whoever designed this interchanges must hate me 
https://www.youtube.com/watch?v=zH5EfvCdPQQ
https://www.youtube.com/watch?v=Xd4-gt9VBeI

The most revolting part about this is the mayor's insistence that the new interchange will somehow attract more retail to the area. What attracts retail is people, and I don't see how people will be attracted to a "divergabout". If they're attracted to areas with little congestion, I doubt this will somehow be the first interchange in the area without any congestion issues. And unless there's significant evidence that rebuilt interchanges routinely attract new retail, nothing will happen here anytime soon. Except maybe some new warehouses (which is fine and sort of expected when interchanges are rebuilt -- that seems to be the only part of his statement I agree with).

I am surprised how complex some interchange designs are, now. Even France, with its bizarre intersection layouts, doesn't have anything like this (though there is a close one in Versailles, with the ramps switching back right before a roundabout -- A13 @ D182).

[skluth]

I wonder how crash-prone this roundabout is.

https://twitter.com/Streetfilms/status/1023739247826632705

Can we find any pedestrian-only roundabouts?

Of course New Jersey would have a bike lane with a jughandle:

There's also this cycling roundabout in the Netherlands.

https://www.welovecycling.com/wide/2016/11/02/dutch-built-elevated-roundabout-just-bikes/
[/url]

[tradephoric]

Since 2005, 7 triple-lane roundabouts have been built in Michigan.  Many of these have since been downsized to double-lane roundabouts and only 3 triple-lane roundabouts remain (18 ½ Mile & Van Dyke; Orchard Lake @ 14 Mile; Martin Pkwy/M-5 @ Pontiac Trail).  Of these 3 triple-lane roundabouts they all made it in the top 5 most crash prone intersections in Michigan for 2017.  Collectively these 3 triple-lane roundabouts experienced 451 crashes last year including 46 injury crashes.  With safety statistics like that, is it any wonder that over half of the triple-lane roundabouts built in Michigan since 2005 have already been downsized?
 

https://www.michiganautolaw.com/blog/2018/05/07/top-20-most-dangerous-mi-intersections/

Another complex triple-lane roundabout at Richmond & Northland in Appleton, Wisconsin was built last year and is approaching one full year of operation.  An article reporting on the early crash data back in February found that there had already been 77 crashes since opening on September 1st.  At that pace the roundabout was on track to experience 181 crashes.  Considering the intersection averaged about 27 crashes/year before the roundabout was built, that's a pretty massive jump (even if the crashes remained at 77).  Now people will say "yeah, but it's only the first year and crashes will go down moving forward".  But just consider that the roundabout at 18 1/2 Mile and Van Dyke was built in 2005 and still experienced 165 crashes last year (including 13 injury crashes).  I wouldn't be at all surprised if the Richmond & Northland roundabout experiences 100+ crashes/year for the foreseeable future.

[Brian556]

Of course New Jersey would have a bike lane with a jughandle:

That's the New Jerseyest thing I've seen yet.

Is that stop sign for vehicular traffic or is it improperly used the mark the end of the wider pavement? The lack of a stop bar, along with its far-forward placement in the intersection makes this situation very unclear

[plain]

Of course New Jersey would have a bike lane with a jughandle:

That's the New Jerseyest thing I've seen yet.

Is that stop sign for vehicular traffic or is it improperly used the mark the end of the wider pavement? The lack of a stop bar, along with its far-forward placement in the intersection makes this situation very unclear

Definitely for bicyclists, not motorists. Basically it's a way to get bicyclists to stop and look before crossing the street here. May would help somewhat if this had a "bicycle" sign or something mounted here too though.

[jakeroot]

Now people will say "yeah, but it's only the first year and crashes will go down moving forward".  But just consider that the roundabout at 18 1/2 Mile and Van Dyke was built in 2005 and still experienced 165 crashes last year (including 13 injury crashes).

It is rather embarrassing that drivers still have such a hard time figuring it out. Maybe if there were more of them? I know Carmel still has a hard time, but one could easily just blame tourists for all the crashes.

I still think the only realistic option to improve roundabout safety is to just put them in everywhere. Of course, if that's actually rather unrealistic, we should probably give up.

What's going on at that Van Dyke/I-696 intersection? Looks pretty well designed to me. I would have to assume side-swipe crashes where the off-ramps meet 11 Mile are the main issue.

[kalvado]

^Only in New Jersey!  While we are on the topic of oddities, are these roundabout guide markings found in the MUTCD anywhere?


https://www.google.com/maps/@41.3343067,-75.7346423,80m/data=!3m1!1e3

Probably would fall under Section 3B.20. Symbol marks are permitted, with no closed list of symbols. 

[kalvado]

Now people will say "yeah, but it's only the first year and crashes will go down moving forward".  But just consider that the roundabout at 18 1/2 Mile and Van Dyke was built in 2005 and still experienced 165 crashes last year (including 13 injury crashes).

It is rather embarrassing that drivers still have such a hard time figuring it out. Maybe if there were more of them? I know Carmel still has a hard time, but one could easily just blame tourists for all the crashes.

I still think the only realistic option to improve roundabout safety is to just put them in everywhere. Of course, if that's actually rather unrealistic, we should probably give up.

What's going on at that Van Dyke/I-696 intersection? Looks pretty well designed to me. I would have to assume side-swipe crashes where the off-ramps meet 11 Mile are the main issue.

(repeating same old tune) general purpose roads are built to be used by regular folks - not by NASCAR drivers, not by roadgeeks, not top 5% drivers exclusively. If road design cannot accommodate 70 year old uncle Tom, then it is a design problem - not uncle Tom's problem. Putting them everywhere is exactly the problem - your doctor doesn't prescribe insulin to every patient. Insulin can be a lifesaver, or a killer, you need to THINK, not blindly build roundabout as a first choice.

I don't like roundabouts, as you may notice. You may blame me for lack of experience - I don't drive them a lot, just through 7 on my daily commute and another 5-6 when I do grocery shopping, and a few on errands. Total of only 50-70, at most 100 passes a week over past few years. Still think most of them are poorly designed.... Maybe I need more practice?

[jakeroot]

(repeating same old tune) general purpose roads are built to be used by regular folks - not by NASCAR drivers, not by roadgeeks, not top 5% drivers exclusively. If road design cannot accommodate 70 year old uncle Tom, then it is a design problem - not uncle Tom's problem. Putting them everywhere is exactly the problem - your doctor doesn't prescribe insulin to every patient. Insulin can be a lifesaver, or a killer, you need to THINK, not blindly build roundabout as a first choice.

I don't like roundabouts, as you may notice. You may blame me for lack of experience - I don't drive them a lot, just through 7 on my daily commute and another 5-6 when I do grocery shopping, and a few on errands. Total of only 50-70, at most 100 passes a week over past few years. Still think most of them are poorly designed.... Maybe I need more practice?

If you hate them because of your experience with other drivers, that's fair. If you hate them because you don't understand them... that's an issue.

I personally like them only where their use makes sense. Just recently, we talked about the WA-20 (Sharpes Corner) roundabouts, and how they were installed to facilitate U-turn maneuvers along a newly-divided stretch of road. They make sense in a situation like this, and from my experience driving them, anything else would have taken up too much room or wouldn't work as well (rural traffic is more random arrival, which is better for roundabouts or fully permissive signals). Compared to the old signal, traffic was moving much better. But, driving around (between the two 7 times in about 20 minutes), I did notice a few close calls. Not collisions, just close calls. This could indicate that actual collisions will be an issue, but we'll have to wait and see. One of the roundabouts is along a popular road linking I-5 to a ferry, with lots of tourists.

Not disagreeing that intersections should be designed to facilitate the movement of driver's of all backgrounds. But drivers of all backgrounds are more readily familiar with the most common types of intersections, of which the roundabout is not one. Signals are a part of nearly all communities across the US, so pretty much all licensed American drivers know how they work because they see one every day. That is not true for roundabouts. Carmel has tons of roundabouts, but Indianapolis has almost none. Any non-Carmel-based driver in Carmel is going to drive through a roundabout, and for our sake, let's hope they can figure out how they work. They'd understand them better if they were used to seeing them. It doesn't take a genius to work that out.

And as I said in my post, roundabouts may not be a realistic solution for all intersections. And if the plan is to slow down how many roundabouts are being installed, we should probably abandon the concept altogether. There are still too many Americans who never see them, and who might be confused or just unphased by the intersection style (and enter in such a way as to unintentionally cause as much carnage as possible -- drifting across lanes, failing to yield, etc). Signals generally work well because they are familiar. Not straightforward. Plenty of signals have bizarre layouts or curves. DDIs, for instance, or Michigan Lefts, but most work OK because drivers are familiar with RYG indications.

[jeffandnicole]

Now people will say "yeah, but it's only the first year and crashes will go down moving forward".  But just consider that the roundabout at 18 1/2 Mile and Van Dyke was built in 2005 and still experienced 165 crashes last year (including 13 injury crashes).

It is rather embarrassing that drivers still have such a hard time figuring it out. Maybe if there were more of them? I know Carmel still has a hard time, but one could easily just blame tourists for all the crashes.

I still think the only realistic option to improve roundabout safety is to just put them in everywhere. Of course, if that's actually rather unrealistic, we should probably give up.

What's going on at that Van Dyke/I-696 intersection? Looks pretty well designed to me. I would have to assume side-swipe crashes where the off-ramps meet 11 Mile are the main issue.

(repeating same old tune) general purpose roads are built to be used by regular folks - not by NASCAR drivers, not by roadgeeks, not top 5% drivers exclusively. If road design cannot accommodate 70 year old uncle Tom, then it is a design problem - not uncle Tom's problem. Putting them everywhere is exactly the problem - your doctor doesn't prescribe insulin to every patient. Insulin can be a lifesaver, or a killer, you need to THINK, not blindly build roundabout as a first choice.

I don't like roundabouts, as you may notice. You may blame me for lack of experience - I don't drive them a lot, just through 7 on my daily commute and another 5-6 when I do grocery shopping, and a few on errands. Total of only 50-70, at most 100 passes a week over past few years. Still think most of them are poorly designed.... Maybe I need more practice?

It helps to know why you think they're poorly designed.  If you're getting thru them unscathed, doesn't sound like you're doing anything wrong.  If you are getting honked yet, then you're probably doing something wrong!

[kalvado]

If you hate them because of your experience with other drivers, that's fair. If you hate them because you don't understand them... that's an issue.

I personally like them only where their use makes sense.

shaking your hand without reading any further. That is exactly my issue, roundabouts built just because - even where adding a turn lane would make things work nicely for a much smaller amount of money (money coming from my taxes after all).

[jakeroot]

If you hate them because of your experience with other drivers, that's fair. If you hate them because you don't understand them... that's an issue.

I personally like them only where their use makes sense.

shaking your hand without reading any further. That is exactly my issue, roundabouts built just because - even where adding a turn lane would make things work nicely for a much smaller amount of money (money coming from my taxes after all).

My bolded point was an attempt to find middle ground. I don't think roundabouts are appropriate for all intersections, but we'd both agree that signals are not appropriate for all either.

You know as well as I do that roundabouts are usually installed to "improve safety", not flow (although I view it as the main benefit, as collisions do seem to become an issue). Improving the signal, as far as some DOTs are concerned, is "putting lipstick on a pig". The argument is not usually "add a turn lane here, or build a roundabout". It's "this signal has a poor safety record, let's install a roundabout".

Now, are these DOT's going off false information? It certainly seems that way! But to tie into my previous post (most of which you seem to have ignored), the safety records of roundabouts could very well be tied to driver unfamiliarity. Of the 165 crashes at the Sterling Heights roundabout (above), how do we know they weren't all drivers who had never seen a roundabout? Your argument is that signals work well because drivers understand them. My argument is (potentially) the same for roundabouts: they would work well if more drivers were familiar with them. Not just the ones who use it every day: all drivers. That's only conceivable if roundabouts become as common as signals. If that's not conceivable, we need to stop installing them immediately.