Crash prone 'modern roundabouts'

[jakeroot]

I think it's about time we get a lock on this topic. It has devolved into a flame war.

It's staying relatively civil. It's had its ups and downs but no one's getting hurt.

While that may be true, the information well is clearly running dry...the post content is once again are taking a circular nature.

Very true. It really has devolved into a roundabout discussion.

[tradephoric]

Had it not been a roundabout, we may be talking more fatalities

It's not a stretch to say someone is a roundabout proponent when they insinuate that a fatal roundabout crash that occurred may have been deadlier if it was another intersection type.  If you take offense to that, sobeit.  The family of Ryan Osler may take offense to certain insinuations too. 

While that may be true, the information well is clearly running dry...the post content is once again are taking a circular nature.

DaBigE, just a week ago you posted the latest crash data for Madison, Wisconsin.  It was used to determine the most up-to-date crash rates for multiple roundabouts in that city (and the finding was they had high crash rates).  That's new and pertinent information for a thread titled "crash prone modern roundabouts".

[DaBigE]

Had it not been a roundabout, we may be talking more fatalities

It's not a stretch to say someone is a roundabout proponent when they insinuate that a fatal roundabout crash that occurred may have been deadlier if it was another intersection type.  If you take offense to that, sobeit.  The family of Ryan Osler may take offense to certain insinuations too.

Making a generalization on a couple data points is a stretch...try publishing a scientific paper on that logic. It's called having an open and scientific mind...looking at all the possibilities and points of view rather than throwing the baby out with the bath water. So, yes, I do take offense to your generalization, just as I would if someone lumped me into one political orientation based on one or two talking points, and just as you appear to when others perpetuate you have an agenda to prove.   

While that may be true, the information well is clearly running dry...the post content is once again are taking a circular nature.

DaBigE, just a week ago you posted the latest crash data for Madison, Wisconsin.  It was used to determine the most up-to-date crash rates for multiple roundabouts in that city (and the finding was they had high crash rates).  That's new and pertinent information for a thread titled "crash prone modern roundabouts".

And what did that information yield? Your same conclusions and discussions made numerous thread pages ago. Also note that data was provided without opinion or much commentary. I could have highlighted the roundabouts that had a decrease in crashes (as a true proponent would do).

[tradephoric]

DaBigE, you have agreed with me in the past that agencies should no longer be promoting the 2000 IIHS study:

For similar reasons, I also disagree with the IIHS study being promoted any further because, as tradephoric also pointed out, it was done on fewer roundabouts and over 15 years ago. A lot has changed within the past 5 years, let alone 15. Similarly, as I've said earlier, many of us (professional colleagues included), have fundamental issues with the studies WisDOT has carried out as well.

Now watch Myth #2 in this video (released in Oct. 2015).  The safety statistics sound oddly familiar.  The t-bone picture at the signalized intersection juxtaposed with the glancing blow of the roundabout was a nice touch for this propaganda piece (I feel justified saying it's a propaganda piece because they are citing safety statistics from the previous century).   Did a 2x3 configuration roundabout even exist in America in the late 90s?  I know they do today.   But according to you I'm the one with the agenda.

https://www.youtube.com/watch?v=HLDdWJzDFyI

[jakeroot]

Did a 2x3 configuration roundabout even exist in America in the late 90s?  I know they do today.

I think one of the first roundabouts in the US was 3x3 (Summerlin, NV), built in the mid 90s:

https://historicaerials.com/?layer=1999&zoom=18&lat=36.17836265443195&lon=-115.31760692596436

[jeffandnicole]

Similar idea but different subject: I've heard people say that when one's using a cell phone, they are 4 times more likely to get in an accident.

I'm still waiting to hear what the probability is of getting in an accident.  And if that's not known, how do you come up with 4 times of an unknown?

[tradephoric]

I could have highlighted the roundabouts that had a decrease in crashes (as a true proponent would do).

Some people favor insinuations over facts.  I have made this challenge before, but cite a multi-lane roundabout (2x2 or 2x3 configuration) that has a crash rate below 1.0 MEV.  A typical signalized intersection has a crash rate of 0.7 MEV so there should be plenty of examples of multi-lane roundabouts with crash rates below 1.0 MEV.  Maybe you will have better luck, but here are the multi-lane roundabouts i could find crash data for and none of them have a crash rate below 1.0 MEV . 



The average crash rate for these multi-lane roundabouts is about 5X higher than a standard signalized intersection.  Even the best performing roundabouts have crash rates double that of a typical traffic signal.  These are very bad results.  They are so bad that many agencies have removed circulating lanes inside the roundabout to address the high crash rates (roundabouts highlighted yellow have had lanes removed).

Making a generalization on a couple data points is a stretch...try publishing a scientific paper on that logic. It's called having an open and scientific mind...

My open and scientific mind is looking at the latest and greatest crash data - not relying on some 15 year old study to determine how effective roundabouts are.  DaBigE, you should be proud that I'm continually updating the crash rates of these multi-lane roundabouts and not lamenting when new data is cited on this thread.

[cl94]

Of course, accident statistics aren't necessarily comparable across intersections and, more importantly, population changes need to be accounted for.

[kalvado]

Of course, accident statistics aren't necessarily comparable across intersections and, more importantly, population changes need to be accounted for.

Oh, come on, you are a transportation engineer! Shame on you for saying something like that.
Just praise the Holy Roundabout! Otherwise you wouldn't find a job, you know..

[cl94]

Of course, accident statistics aren't necessarily comparable across intersections and, more importantly, population changes need to be accounted for.

Oh, come on, you are a transportation engineer! Shame on you for saying something like that.
Just praise the Holy Roundabout! Otherwise you wouldn't find a job, you know..

I'm on the research side. I don't give a damn about the propaganda, I just want to know how stuff truly compares.

[DaBigE]

Making a generalization on a couple data points is a stretch...try publishing a scientific paper on that logic. It's called having an open and scientific mind...

My open and scientific mind is looking at the latest and greatest crash data - not relying on some 15 year old study to determine how effective roundabouts are.  DaBigE, you should be proud that I'm continually updating the crash rates of these multi-lane roundabouts and not lamenting when new data is cited on this thread.

The only thing anyone is lamenting is the lack of new discussion. It's the same song and dance each time... crashes are not going down, crashes are going up, yada, yada, yada. Great, there's new numbers...what myself and I can only assume others are waiting for is new action to be taken to correct the number of crashes. I'm guessing nearly no one that is a member of this forum has any power to change how policy and research are being done, so posting new data is by and large a waste of energy and only serving to decrease the number of interested readers.

And until new research or design action comes out, I'm not going to waste any more energy responding to cherry-picked quotes in this thread.

Are roundabouts perfect? No. Are they a silver-bullet solution? Not even close. What they are is another tool in the toolbox -- a tool which is still working thru some R&D revisions.

[kalvado]

Making a generalization on a couple data points is a stretch...try publishing a scientific paper on that logic. It's called having an open and scientific mind...

My open and scientific mind is looking at the latest and greatest crash data - not relying on some 15 year old study to determine how effective roundabouts are.  DaBigE, you should be proud that I'm continually updating the crash rates of these multi-lane roundabouts and not lamenting when new data is cited on this thread.

The only thing anyone is lamenting is the lack of new discussion. It's the same song and dance each time... crashes are not going down, crashes are going up, yada, yada, yada. Great, there's new numbers...what myself and I can only assume others are waiting for is new action to be taken to correct the number of crashes. I'm guessing nearly no one that is a member of this forum has any power to change how policy and research are being done, so posting new data is by and large a waste of energy and only serving to decrease the number of interested readers.

And until new research or design action comes out, I'm not going to waste any more energy responding to cherry-picked quotes in this thread.

Are roundabouts perfect? No. Are they a silver-bullet solution? Not even close. What they are is another tool in the toolbox -- a tool which is still working thru some R&D revisions.

I, for one, absolutely pissed off with the fact that roundabouts are sold as silver bullets. I am not sure what is needed to reverse the trend of Holy Roundabouts construction. 
Of course, there is not much we can do on this forum. But I don't see what can be done  in general... Seems like too much money is involved.

[kalvado]

Of course, accident statistics aren't necessarily comparable across intersections and, more importantly, population changes need to be accounted for.

Oh, come on, you are a transportation engineer! Shame on you for saying something like that.
Just praise the Holy Roundabout! Otherwise you wouldn't find a job, you know..

I'm on the research side. I don't give a damn about the propaganda, I just want to know how stuff truly compares.

Count me in.. and lets keep dreaming..
On research side, however,  only real papers I found are dealing with minor street joining arterial, which makes some sense.

[tradephoric]

The only thing anyone is lamenting is the lack of new discussion. It's the same song and dance each time... crashes are not going down, crashes are going up, yada, yada, yada. Great, there's new numbers...what myself and I can only assume others are waiting for is new action to be taken to correct the number of crashes. I'm guessing nearly no one that is a member of this forum has any power to change how policy and research are being done, so posting new data is by and large a waste of energy and only serving to decrease the number of interested readers.

And until new research or design action comes out, I'm not going to waste any more energy responding to cherry-picked quotes in this thread.

You are diminishing the importance of new crash data, you accuse me of having an agenda when other agencies are citing statistics from the previous century, you ignore my request to cite a 2x2 multi-lane roundabout with a crash rate below 1.0 MEV, and you grumble that the thread is "˜going in circles' when I respond to your accusations.  Should I care if you leave?

It's amazing that there isn't a single example of a multi-lane roundabout (2x2) that has a crash rate below that of a standard signalized intersection.  Agencies can keep pushing their propaganda that these multi-lane roundabouts reduce total crashes, but it's not true.

[jakeroot]

It's amazing that there isn't a single example of a multi-lane roundabout (2x2) that has a crash rate below that of a standard signalized intersection.

...that you know of.

Your list contains dozens of multi-lane roundabouts, but according to Roundabouts USA, there were nearly five thousand roundabouts in the US by the end of last year (source). Of course most of these are single lane, but there are hundreds that aren't. And the bottom of your list, while still not below 1 MEV, gets pretty close (last I remember seeing, at least--your table isn't showing up for me anymore). The chance of there being multi-lane roundabouts with crash rates below 1 MEV is pretty likely. We just need numbers that aren't publicly available (or better yet, a comprehensive modern-day study from the FHWA).

[kalvado]

We just need numbers that aren't publicly available (or better yet, a comprehensive modern-day study from the FHWA).

Wow, looks like you started to change your mind! First step is always the most difficult one... And welcome to the club!

[jakeroot]

We just need numbers that aren't publicly available (or better yet, a comprehensive modern-day study from the FHWA).

Wow, looks like you started to change your mind! First step is always the most difficult one... And welcome to the club!

Despite what I've said in the past, I very much agree with tradephoric that the oft-cited study is simply too old to be relevant. We definitely need a new, more comprehensive study.

Where I've disagreed with him in the past is with his propensity to declare all multi-lane roundabouts to be duds, based on the data of the several dozens that he's found. I'm not saying his research isn't appreciated -- it is, and it's definitely opened some eyes. But we need to study all of the roundabouts in America before we come to a conclusion.

[lordsutch]

It's amazing that there isn't a single example of a multi-lane roundabout (2x2) that has a crash rate below that of a standard signalized intersection.  Agencies can keep pushing their propaganda that these multi-lane roundabouts reduce total crashes, but it's not true.

I've restrained myself from wading back into this thread, but I will agree that transportation departments shouldn't make the claim roundabouts will reduce the incidence rate of total crashes or property-damage only crashes over signalized intersections, because that's not borne out by the evidence in the general case. And I'll gladly concede that roundabouts - constructed against engineering guidance - that have fixed objects in the island should have been properly engineered.

However, I think you need to be willing to concede that roundabouts - even multilane roundabouts - do in general reduce the incidence of injury and fatality crashes, even if they don't prevent all of them (which has never been claimed by anyone, to my knowledge). In fact that's the key trade-off - with roundabouts, you get some more low-angle of incidence, lower-speed crashes in return for fewer 90-degree, high-speed crashes, which are the ones (particularly with today's safety technologies) are the most dangerous.

Does that mean I (and others) have callous disregard for the deaths and injuries that remain, as you have stated on several occasions? Of course not, and such an implication is frankly offensive. No intersection is perfect or (as DaBigE puts it) a "silver bullet," particularly when you have high traffic volumes. But unless you think that some human lives have more intrinsic value than other human lives, an option that results in fewer injuries and deaths overall is preferable to one that results in more of them, even if some deaths and injuries are going to happen either way. That doesn't bring back specific crash victims who might not have died in the counterfactual universe where there was a different intersection, but it does mean that more people didn't die in their place.

And I will say that if your beef boils down to (like kalvado's appears to boil down to) "transportation agencies are making false/exaggerated claims about total crash rates," this thread appears to have run its course and you need to address yourself elsewhere, because transportation agencies and their media representatives aren't reading random threads on Internet message boards to decide how they will communicate with the public.

But we need to study all of the roundabouts in America before we come to a conclusion.

This. Unless you're studying the entire population of interest, you're going to arrive at bad conclusions. Otherwise you end up being the guy on Twitter claiming that Trump is winning the election because he got a few million votes on a Drudge Report web poll.

[DaBigE]

It's amazing that there isn't a single example of a multi-lane roundabout (2x2) that has a crash rate below that of a standard signalized intersection.  Agencies can keep pushing their propaganda that these multi-lane roundabouts reduce total crashes, but it's not true.

I've restrained myself from wading back into this thread, but I will agree that transportation departments shouldn't make the claim roundabouts will reduce the incidence rate of total crashes or property-damage only crashes over signalized intersections, because that's not borne out by the evidence in the general case. And I'll gladly concede that roundabouts - constructed against engineering guidance - that have fixed objects in the island should have been properly engineered.

However, I think you need to be willing to concede that roundabouts - even multilane roundabouts - do in general reduce the incidence of injury and fatality crashes, even if they don't prevent all of them (which has never been claimed by anyone, to my knowledge). In fact that's the key trade-off - with roundabouts, you get some more low-angle of incidence, lower-speed crashes in return for fewer 90-degree, high-speed crashes, which are the ones (particularly with today's safety technologies) are the most dangerous.

Does that mean I (and others) have callous disregard for the deaths and injuries that remain, as you have stated on several occasions? Of course not, and such an implication is frankly offensive. No intersection is perfect or (as DaBigE puts it) a "silver bullet," particularly when you have high traffic volumes. But unless you think that some human lives have more intrinsic value than other human lives, an option that results in fewer injuries and deaths overall is preferable to one that results in more of them, even if some deaths and injuries are going to happen either way. That doesn't bring back specific crash victims who might not have died in the counterfactual universe where there was a different intersection, but it does mean that more people didn't die in their place.

And I will say that if your beef boils down to (like kalvado's appears to boil down to) "transportation agencies are making false/exaggerated claims about total crash rates," this thread appears to have run its course and you need to address yourself elsewhere, because transportation agencies and their media representatives aren't reading random threads on Internet message boards to decide how they will communicate with the public.

^This. The only thing missing is a mic drop.

The only thing anyone is lamenting is the lack of new discussion. It's the same song and dance each time... crashes are not going down, crashes are going up, yada, yada, yada. Great, there's new numbers...what myself and I can only assume others are waiting for is new action to be taken to correct the number of crashes. I'm guessing nearly no one that is a member of this forum has any power to change how policy and research are being done, so posting new data is by and large a waste of energy and only serving to decrease the number of interested readers.

And until new research or design action comes out, I'm not going to waste any more energy responding to cherry-picked quotes in this thread.

You are diminishing the importance of new crash data, you accuse me of having an agenda when other agencies are citing statistics from the previous century, you ignore my request to cite a 2x2 multi-lane roundabout with a crash rate below 1.0 MEV, and you grumble that the thread is "˜going in circles' when I respond to your accusations.  Should I care if you leave?

You do have a way with words. Replace "last century" with "20 years ago" and see if there's a change in the drama of that statement. No one is diminishing the importance of new data, far from it, actually. We're saying your point has been proven time and time again. New numbers aren't changing anything, unfortunately. That is where this thread is going in circles. Me pointing this out again is further evidence. And it's not that I give a shit whether you care or not, rather, it's my way of saying don't bother targeting me in your posts. No other data I have access to will add anything new to this discussion. You have the same access to the internet as I.

And since you like to twist and throw my words back at me, I chose to respond since for a change you didn't cherry-pick something in your post

[kalvado]

And I will say that if your beef boils down to (like kalvado's appears to boil down to) "transportation agencies are making false/exaggerated claims about total crash rates," this thread appears to have run its course and you need to address yourself elsewhere, because transportation agencies and their media representatives aren't reading random threads on Internet message boards to decide how they will communicate with the public.

Well, let me expand my point a little bit.
My impression is that roundabouts are controversial enough (this thread may be the evidence) for the issues to be addressed with some more detailed analysis. And - as pretty even jakeroot has admitted - there is no such analysis available to general public. Compare that with SPUI, for example - although there is much lower number, but they seem  way less controversial for general public.
Now... why would such structures be built in large number without looking at public input? My two possible answers are indoctrination and corruption. And my bet is that its not even about transportation officials, it is about election money.
And, if you think about it, roundabouts are expensive. I've seen anything between $1.5M and $15M... 1% or even 0.1% of such contract is a sizeable chunk of money...

Yes, roundabout is definitely another tool in the box. But it takes some learning to use proper tools - and learning is something I don't see. But I see a lot of situations where tool is used in a way someone else would use sledgehammer on screws.

I am not against ALL roundabouts, I am against those built without understanding of usability ..... which seem to be most of them, unfortunately.

[DaBigE]

Well, let me expand my point a little bit.
My impression is that roundabouts are controversial enough (this thread may be the evidence) for the issues to be addressed with some more detailed analysis. And - as pretty even jakeroot has admitted - there is no such analysis available to general public. Compare that with SPUI, for example - although there is much lower number, but they seem  way less controversial for general public.

But when you boil it down, a SPUI is still a traffic signal. Movements are still largely the same as a conventional cross intersection. IMO, that is why SPUIs aren't as controversial. Going right to ultimately turn left in a roundabout? That logic still blows the mind of a lot of people. It disrupts the binary thought process so many drivers are entrenched in. And we should begin to see more transparency in the decision process of intersection controls as ICE (Intersection Control Evaluation) reports become more common. Each state may have a slightly different format to them, but they're a part of public record (at least for state-run projects), so you should be able to request to see them. Wisconsin has had them for a few years, MnDOT uses a form of ICE as does Illinois (I believe they're called IDS reports), and GDOT is working on implementing them. Other states may be in various stages of use as well, but they're out of my normal work area.

...But it takes some learning to use proper tools - and learning is something I don't see. But I see a lot of situations where tool is used in a way someone else would use sledgehammer on screws.

I would agree with that on many levels...drivers, engineers, and politicians. But I do see the general opinion of roundabouts losing a bit of controversy. It used to be where you'd look at the comments section of a news story regarding a roundabout and you'd see nearly 100% of commenters against any and all roundabouts. You still see a lot of negativity, but there's also a big upswing in the number of people with positive things to say. I've witnessed similar experiences in various PIMs I've been to recently.

[tradephoric]

You do have a way with words. Replace "last century" with "20 years ago" and see if there's a change in the drama of that statement.

Go ahead and replace "last century"  with "20 years ago" .  That's fine.  Some members here weren't even alive 20 years ago.  What's dramatic is that agencies still push safety statistics from such an old study.

No one is diminishing the importance of new data, far from it, actually. We're saying your point has been proven time and time again. New numbers aren't changing anything, unfortunately. That is where this thread is going in circles.

I don't understand what you are getting at.  Should we stop citing new crash prone modern roundabouts simply because there are already examples of crash prone modern roundabouts?  Kalvado just mentioned SPUIs... what if somebody started a thread wanting to know the location of every SPUI in America.  Should that compilation of data stop once some arbitrary number of SPUI locations is determined?  I guess compiling a database of SPUIs is less controversial than compiling a database of crash prone modern roundabouts.

I like to piecemeal posts so i can respond to individual points.  I'm not trying to cherry-pick.

[kalvado]

Well, let me expand my point a little bit.
My impression is that roundabouts are controversial enough (this thread may be the evidence) for the issues to be addressed with some more detailed analysis. And - as pretty even jakeroot has admitted - there is no such analysis available to general public. Compare that with SPUI, for example - although there is much lower number, but they seem  way less controversial for general public.

But when you boil it down, a SPUI is still a traffic signal. Movements are still largely the same as a conventional cross intersection. IMO, that is why SPUIs aren't as controversial. Going right to ultimately turn left in a roundabout? That logic still blows the mind of a lot of people. It disrupts the binary thought process so many drivers are entrenched in. And we should begin to see more transparency in the decision process of intersection controls as ICE (Intersection Control Evaluation) reports become more common. Each state may have a slightly different format to them, but they're a part of public record (at least for state-run projects), so you should be able to request to see them. Wisconsin has had them for a few years, MnDOT uses a form of ICE as does Illinois (I believe they're called IDS reports), and GDOT is working on implementing them. Other states may be in various stages of use as well, but they're out of my normal work area.

...But it takes some learning to use proper tools - and learning is something I don't see. But I see a lot of situations where tool is used in a way someone else would use sledgehammer on screws.

I would agree with that on many levels...drivers, engineers, and politicians. But I do see the general opinion of roundabouts losing a bit of controversy. It used to be where you'd look at the comments section of a news story regarding a roundabout and you'd see nearly 100% of commenters against any and all roundabouts. You still see a lot of negativity, but there's also a big upswing in the number of people with positive things to say. I've witnessed similar experiences in various PIMs I've been to recently.

I used SPUI as an example of novel structure which is accepted without major issue. And having oncoming traffic on your right is counter-intuitive as well for me. I still have to experience diverging diamond, so I didn't talk about that, but may be a fair comparison as well. 

Roundabout for me are not a totally new thing, not more than SPUI. More like a mandatory turn on red. If you buy that interpretion,  underlying movement - turn on red - is fairly common in US and shouldn't be an issue. Yet I see many people unhappy, but still force fed new circles. Yes, there is some degree of acceptance... But people tend to get used to many things, and that doesn't prove safety or convenience. Moreover, given significant level of opposition after so many years...
That is why I don't take DOT(using term lousily) pro-circle arguments at face value.

 

[DaBigE]

Roundabout for me are not a totally new thing, not more than SPUI. More like a mandatory turn on red. If you buy that interpretion,  underlying movement - turn on red - is fairly common in US and shouldn't be an issue. Yet I see many people unhappy, but still force fed new circles. Yes, there is some degree of acceptance... But people tend to get used to many things, and that doesn't prove safety or convenience. Moreover, given significant level of opposition after so many years...
That is why I don't take DOT(using term lousily) pro-circle arguments at face value.

I like that comparison...I think it fits the situation very well. Multilane roundabouts should, in theory be not much different than a RTOR from a dual-lane right turn approach.

One of the biggest reasons for the force-feeding of many roundabouts is to be due to federal HSIP funding structure. Many of those grants are tied specifically to the construction of roundabouts, due to the outdated IIHS information. Until a new study of similar size is done, good luck getting the feds to take off the rose-colored glasses. Unfortunately, no roundabout = no money for an improvement project, so many cash-strapped agencies will swallow the bitter roundabout pill in order to be seen as doing something to improve a safety problem.

[DaBigE]

You do have a way with words. Replace "last century" with "20 years ago" and see if there's a change in the drama of that statement.

Go ahead and replace "last century"  with "20 years ago" .  That's fine.  Some members here weren't even alive 20 years ago.  What's dramatic is that agencies still push safety statistics from such an old study.

Hate to break it to you, but there are other design decisions based on data that is much older. Unfortunately, many agencies don't have the money to fill all their potholes, let alone fund proper, revised safety studies.

I like to piecemeal posts so i can respond to individual points.  I'm not trying to cherry-pick.

There's obviously a lot more you don't get (or don't want to admit to doing)...you cherry-pick parts of statements, many times out of context to make it sound like we're saying something we're not.