Crash prone 'modern roundabouts'

[kphoger]

That's exactly why I don't think roundabouts are a bad idea, but I just think DOTs - or their equivalents - should not be allowed to build those until they have at least 50 years of experience in building roundabouts.

What is exactly why you think they shouldn't?  Everything he posted makes total sense to me, and it's the way I think roundabouts should be designed and function.  Whenever I've driven a roundabout that was striped like that (such as this one or this one), it was intuitive to use.

[kalvado]

That's exactly why I don't think roundabouts are a bad idea, but I just think DOTs - or their equivalents - should not be allowed to build those until they have at least 50 years of experience in building roundabouts.

What is exactly why you think they shouldn't?  Everything he posted makes total sense to me, and it's the way I think roundabouts should be designed and function.  Whenever I've driven a roundabout that was striped like that (such as this one or this one), it was intuitive to use.

It's more global. There is no institutional understanding of what is being built.
There are old style traffic circles with one set of rules, there are "modern" turbo  roundabouts with another set of rules.
We are talking about some random mixture of concepts being built, with serious problems due to squeezing them into minimal possible footprint (as they happen in already built-up areas), with serious problems for nonhcar traffic (both big vehicles and pedestrians) and no trend for improvement.
I can buy a "learning curve" explanation - but after 20 years it's not a learning curve, it should become a dropout.

[Rothman]

That's exactly why I don't think roundabouts are a bad idea, but I just think DOTs - or their equivalents - should not be allowed to build those until they have at least 50 years of experience in building roundabouts.

What is exactly why you think they shouldn't?  Everything he posted makes total sense to me, and it's the way I think roundabouts should be designed and function.  Whenever I've driven a roundabout that was striped like that (such as this one or this one), it was intuitive to use.

It's more global. There is no institutional understanding of what is being built.
There are old style traffic circles with one set of rules, there are "modern" turbo  roundabouts with another set of rules.
We are talking about some random mixture of concepts being built, with serious problems due to squeezing them into minimal possible footprint (as they happen in already built-up areas), with serious problems for nonhcar traffic (both big vehicles and pedestrians) and no trend for improvement.
I can buy a "learning curve" explanation - but after 20 years it's not a learning curve, it should become a dropout.

I find this an uninformed extreme position given my own experience and even despite some problematic implementations of roundabouts.  The idea that there is no state of the art ("institutuonal understanding") regarding roundabout design is absolutely ridiculous as there are indeed standards and expertise that are brought to bear for such.  We're at the point where, at least in NY, the vast majority of roundabout projects are not problematic.

It's not like mistakes aren't made here and there in transportation projects across the board, anyway.  Society will continue to fix such as if warranted.

[kphoger]

It's more global. There is no institutional understanding of what is being built.
There are old style traffic circles with one set of rules, there are "modern" turbo  roundabouts with another set of rules.
We are talking about some random mixture of concepts being built, with serious problems due to squeezing them into minimal possible footprint (as they happen in already built-up areas), with serious problems for nonhcar traffic (both big vehicles and pedestrians) and no trend for improvement.
I can buy a "learning curve" explanation - but after 20 years it's not a learning curve, it should become a dropout.

But you responded to a post highlighting how uniform the expectations are between Alberta and Ontario as to lane usage—and which others have already pointed out is the expectation in other places as well.  This sounds to me like more of a global understanding than you're giving it credit for.  The only examples I've seen on here—from you—of where it's OK to switch lanes between entering and exiting a roundabout have been where it's clearly striped to allow it, to the point that it barely counts as changing lanes at all.

[kalvado]

That's exactly why I don't think roundabouts are a bad idea, but I just think DOTs - or their equivalents - should not be allowed to build those until they have at least 50 years of experience in building roundabouts.

What is exactly why you think they shouldn't?  Everything he posted makes total sense to me, and it's the way I think roundabouts should be designed and function.  Whenever I've driven a roundabout that was striped like that (such as this one or this one), it was intuitive to use.

It's more global. There is no institutional understanding of what is being built.
There are old style traffic circles with one set of rules, there are "modern" turbo  roundabouts with another set of rules.
We are talking about some random mixture of concepts being built, with serious problems due to squeezing them into minimal possible footprint (as they happen in already built-up areas), with serious problems for nonhcar traffic (both big vehicles and pedestrians) and no trend for improvement.
I can buy a "learning curve" explanation - but after 20 years it's not a learning curve, it should become a dropout.

I find this an uninformed extreme position given my own experience and even despite some problematic implementations of roundabouts.  The idea that there is no state of the art ("institutuonal understanding") regarding roundabout design is absolutely ridiculous as there are indeed standards and expertise that are brought to bear for such.  We're at the point where, at least in NY, the vast majority of roundabout projects are not problematic.

It's not like mistakes aren't made here and there in transportation projects across the board, anyway.  Society will continue to fix such as if warranted.

Well, you probably know that I live in Malta NY, a wanna-be Carmel Jr.  And I am not enchanted with NYSDOT design quality in general, nor roundabouts in particular. 
Let's focus on roundabout design for now. Just remember that NYSDOT designed roundabouts made the top of the list of most crash prone ones in Albany area. Yes, less fatal - but still, millions invested for making one to go on top of crash list?
More specific examples:
 Do you think that NYSDOT ones on Rt.9 in Malta are turbo or not? What does NYS V&T have to say about lane change within the circle - turbo style or circle style? Although it is "barely counts" as @kphoger says, it is certainly something road designer has to know with absolute certainty, and implement so that movements fully conform to traffic laws...

[tradephoric]

Studies have shown that roundabouts reduce fatal crashes by 90% compared to traditional intersections.  There are roughly 330k traffic signals in America and 10k roundabouts.  What is the probability that the deadliest intersection in America would be at a roundabout?  How would you solve this?

[kphoger]

Well, that didn't take long to find...

[kphoger]

What does NYS V&T have to say about lane change within the circle - turbo style or circle style?

To answer this specific question:  while New York state traffic law defines a roundabout as an intersection, it appears that changing lanes within an intersection is not prohibited there.