Advocacy & Safety - Roundabout/TrafficCirle

Somebody posted a definition of a traffic circle and a roundabout that seemed to me to be a distinction without a difference.
I guess there is no difference.
http://www.dot.ca.gov/dist07/travel/projects/roundabout/
http://www.pe.com/localnews/rivcounty/stories/PE_News_Local_S_circle21.46d763e.html
My thought is that they cause more problems than they solve. Namely accidents.
dc

they're amazing if people know the rules on them - they don't in the USA from what people have told me

and the big ones are not so safe because they're even more dangerous when people have no clue

edit: that roundabout in the picture is pretty safe, we have four lane ones here. I ride on them, but I take the lane and make sure people don't pass me from the right etc.
You should definately only do this if you are comfortable looking around, otherwise it's unmanageable

Actually, studies have shown that roundabouts are typically safer than other sorts of intersections, and have the added advantage of keeping all traffic moving while calming it at the same time. The one exception, unfortunately, is that they are more hazardous to cyclists. I am guessing that it's because cyclists are generally (1) somewhat unexpected, and (2) harder to notice in a roundabout. In a car, I would always scan the other sides of the roundabout before entering to make sure I am yielding to anyone who's currently in it. A bicycle is smaller and less noticeable. The best thing that can be done is (1) take the lane at a roundabout, and (2) invest big-time in visibility aids such as a headlight/taillight/vests, etc. FWIW, side visibility, talked about on other threads, may be most valuable at a roundabout since people are scanning in all directions. A roundabout that was constructed as a solution to backed-up traffic in town here (Northshore Dr and Concord Rd) has earned high marks after initially drawing much opposition.

A traffic circle is different from a roundabout. IIRC they're typically larger, and have opportunities for people to weave and so forth, and different yielding rules. I'm fairly sure they've been deprecated.

What gets me is the magic roundabouts.... or a roundabout of roundabouts:

http://www.bbc.co.uk/wiltshire/content/images/2007/10/22/msn_magic_roundabout_470x350.jpg

Still, I've driven in England and I agree that they are very, very, very effective at sorting out traffic at intersections that, in the U.S., could only be sorted out with traffic lights. But with roundabouts, when traffic is light, you never have to stop and wait for the light to cycle through.

In England, some roundabouts are supplemented with traffic lights for rush hour traffic in areas where when it is busy it gives all directions a chance at getting through.

I think yield signs and all-way-stops (possibly all way yield?) would be a great solution - They have way more give way signs than roundabouts in England, and you don't need nearly as much land. We have two all-way-stops between relatively busy rural roads around where I live, and I never have to wait more than 2-3 seconds to get through (even in a car).

Another thing is to get rid of the left turn light at signalized intersections - I don't get why 1 person waiting to turn left gets to go before 20+ people waiting to go straight, when he could just wait for the 20 to pass and then turn.

Also, there should be way more flashing reds on weekends. Traffic lights tend to annoy me incredibly when I'm in my cage...(probably cuz I don't typically obey them on a bike)

There is a difference in how I interpret them..... I think of traffic circles as small, neighborhood planter circle type of traffic calming device placed in the middle of existing low ADT intersections, and roundabouts as much larger traffic sorting and queing devices built onto arterials and higher ADT thoroughfares- even state highways.

I had a hick in a pickup yell at me to yield to him in a newly minted state highway roundabout out in the sticks despite me having entered it ahead of him. They've been implementing in in the Northwest with some regularity, even the heinously disorienting (in a car) multiple sets of roundabouts in rural-burbia.

The rules are the same, whether it's a roundabout or traffic circle. If you are inside the circle, you have the right of way, and those wanting to enter the circle have to yield. The problem is, at least here in Miami, Florida, the drivers don't understand the rules.

It happens all the time that as I am approaching the circle, that cars inside the circle stop to let me in.

Also, it frequently happens that cars that are approaching the circle on multilane, fast-moving roads, think that they have the right-of-way and don't have to yield to traffic inside the circle.

Those are the rules, but unfortunately few who know them or follow them, so be prepared.

They put one outside my city recently but never gave anyone the rules for it so no one knows what to do.

Modern Roundabouts (http://www.azdot.gov/CCPartnerships/Roundabouts/index.asp)

More (http://www.azdot.gov/CCpartnerships/roundabouts/AZ_Roundabouts.asp)

I wish they had done something like that here, people stop going into it, etc.

http://www.azdot.gov/CCpartnerships/roundabouts/L202_8.asphttp://www.azdot.gov/CCpartnerships/roundabouts/L202_8.asphttp://www.azdot.gov/CCpartnerships/roundabouts/L202_8.asp

I'd like it if they replaced arterial street intersections with roundabouts and dropped the speed limit to 25 mph.

traffic circle vs. roundabout

http://www.camrose.com/engineer/roundabouts/circle_vs_roundabout.htm

History
http://www.azdot.gov/CCPartnerships/Roundabouts/History.asp

We have them in New England, it is called a Rotary. Easy to use, just put down the cell phone first.

VDOT is big on roundabouts these days. We're getting a big one in Blacksburg to replace the signal at one of our major intersections. They installed one on the VT campus a couple of years ago, and we'll be getting a few more around town too.

* The biggest safety benefit is that everyone is moving in the same direction, so no deadly head-on or T-bone accidents

* Everyone's going slower so reaction times are adequate

* Traffic keeps moving unless it's really heavy, and it almost always flows better than with a signal

* It's much better for air quality and noise -- vehicles don't sit idling, and they burn less fuel when they don't have to accelerate from a complete stop

The main problem with roundabouts is that they may need more real estate.

Oh by the way they don't need electricity.

I like the smaller ones with single lane feeders and one central circular "lane". These slow traffic down enough so it's easy to take the lane and flow through with everyone else.

The main problem with roundabouts is that they may need more real estate.

Back in my hometown of Omaha, NE, they put in a roundabout/rotary/traffic circle with some, uh, adjustments so that they wouldn't have to take out a gas station and a few houses:

http://maps.google.com/maps?f=q&source=s_q&hl=en&geocode=&q=Omaha,+NE&sll=37.0625,-95.677068&sspn=44.204685,74.794922&ie=UTF8&ll=41.274251,-95.990306&spn=0.002572,0.004565&t=h&z=18

Pic attached.

It used to be that there were three "intersections" -- Happy Hollow and 50th, N Saddle Creek - 50th - Seward, and Country Club-Happy Hollow-Saddle Creek. However, there was only one stop sign in any direction, so, for example, someone driving westbound on Happy Hollow would only stop at 50th before crossing there and the big intersection with Saddle Creek and Happy Hollow. The trouble was, not everybody could figure out where the other stop signs were and how to yield to each other, so you'd have people advancing out of turn or stopping for no reason at all just halfway across.

"The Peanut", as it's been nicknamed, is much better. It also has a lot of signage saying to yield to traffic coming from the left around the nut.

I can think of a similarly large intersection in my neighborhood that would benefit from changing to a traffic circle (or even a "peanut"). Not totally sure how it would affect other intersections nearby, but it would eliminate people having to idle for no cross traffic. Pedestrian crossings would be a puzzle, though.

And, I agree, not enough people know how to handle roundabouts here. There are a lot in DC that are crippled with traffic signals, nearly defeating the purpose of their existence.

And, I agree, not enough people know how to handle roundabouts here. There are a lot in DC that are crippled with traffic signals, nearly defeating the purpose of their existence.

no doubt some government official trying to fix a non problem...

We have three relatively new traffic circles in my neighborhood, and I generally like them because they have very tight radii of curvature, 15mph/25kph design speeds, only one lane within the circle, and yield signs at all four entrances. I strongly oppose multi-lane high-speed roundabouts, because they are deathtraps for bicyclists and pedestrians.

As a cyclist, the central thing to remember about them is to take the inner lane until you get to your exit, or else you are going to be merging at every entrance and exit you pass. And if you don't get a chance to merge out to your exit, you can just go around again!

Unfortunately, I've heard of some traffic circles where some genius has placed a sidepath for bikes around the outside of the circle, which is exactly where you don't want to be! You'll be in potential conflict at every leg.

All roundabouts are traffic circles but not all traffic circles are roundabouts.


And, I agree, not enough people know how to handle roundabouts here. There are a lot in DC that are crippled with traffic signals, nearly defeating the purpose of their existence.
If it has traffic signals or stop signs, it's not a roundabout.

Roundabouts rock. On my bike I rarely have to even slow down, even at busy intersections. In my car I never have much of a wait.

Roundabouts are deadly for pedestrians, and especially blind and handicapped peds. They shouldn't be used in urban areas for that reason. In less crowded areas, there should be safe crosswalks with walk signals for the pedestrians.

I have no problem with roundabouts on my bike. The biggest ones that I've used are only two lanes. Are the bigger ones harder to use?

Roundabouts are deadly for pedestrians,

Who says, besides just you?

Who says, besides just you?

Advocates for blind pedestrians have been raising this issue. There are design modifications that can make roundabouts safer for peds, such as traffic splitting islands, and crosswalks placed well in advance of the roundabout. Roundabouts in pedestrian dense areas have been designed with stop signs at the crosswalks. Unfortunately, this obviates the main advantage of roundabouts, which is providing for a free flow of traffic through the intersection.



There is a need for research on this topic as well as a broad range of other pedestrian-related concerns at roundabouts. Little is known about the effect of roundabouts on older pedestrians, children, and pedestrians with disabilities. Anecdotal evidence indicates that many Australian engineers (who have extensive experience with roundabouts) consider these intersections to be unsuitable if large numbers of pedestrians are present.

The differences between modern roundabouts and traditional intersections controlled by traffic signals and stop signs have important implications for blind pedestrians. While some of these implications are not yet well understood, they must be considered by any transportation engineer or planner whose goal is to create an accessible pedestrian environment.

http://www.access-board.gov/research/roundabouts/bulletin.htm


If you're really interested (which I doubt), you might want to walk to a roundabout, close your eyes, and figure out how you're going to cross it. Good luck!

In a car, I would always scan the other sides of the roundabout before entering to make sure I am yielding to anyone who's currently in it.

At a properly designed roundabout with a centre landscaped island you should only be looking to your left.

In a car, I would always scan the other sides of the roundabout before entering to make sure I am yielding to anyone who's currently in it.

At a properly designed roundabout with a centre landscaped island you should only be looking to your left.

And to ones right so as not to run over someone

Roundabouts are deadly for pedestrians, and especially blind and handicapped peds. They shouldn't be used in urban areas for that reason. In less crowded areas, there should be safe crosswalks with walk signals for the pedestrians.

Excluding the blind and handicapped pedestrians for a moment, I thought that the evidence was that it made it safer for everyone. My memory is fuzzy, but what I thought they used were before and after "natural experiments" comparing collisions for the pedestrian assertion. Is there evidence to the contrary?

Re: pedestrian safety. They can be difficult when crossing a road a driver is exiting the roundabout. Given that, even in the UK, correctly signalling that they are leaving the roundabout is something that a large majority (IMHE) fail to do and that, in many cases, they don't appear to know what the rules for signalling are, you will often see pedestrians "hovering" at the edge of the sidewalk (or, as we call it, the pavement), unsure of a driver's intentions.

There is also the fact that, the larger the roundabout, the higher the traffic speed and the more serious the consequence of any error on the part of the pedestrian in misreading the driver's intended manoeuvre.

Re: pedestrian safety. They can be difficult when crossing a road a driver is exiting the roundabout. Given that, even in the UK, correctly signalling that they are leaving the roundabout is something that a large majority (IMHE) fail to do and that, in many cases, they don't appear to know what the rules for signalling are, you will often see pedestrians "hovering" at the edge of the sidewalk (or, as we call it, the pavement), unsure of a driver's intentions.

There is also the fact that, the larger the roundabout, the higher the traffic speed and the more serious the consequence of any error on the part of the pedestrian in misreading the driver's intended manoeuvre.

But is it the case that someone empirically demostrated that making an intersection a roundabout or vice versa made matters worse for pedestrian safety?

But is it the case that someone empirically demostrated that making an intersection a roundabout or vice versa made matters worse for pedestrian safety?

Well, if traffic never stops, but flows constantly, I could see where this might be an issue for pedestrians.

Locally small diameter roundabouts, along with narrowing the roadway, have been used to calm (slow down) high speed traffic. The traffic throughput has decreased slightly, but the speed of motor traffic has slowed dramatically. (motorists used to well exceed the 35MPH speed limit as they "raced" between stop signs) But the issue for pedestrians is that the motor traffic doesn't stop. Before, at stop signs, there was at least a time and place for peds to cross. As it is with the small roundabouts, the best place to cross now is at the input flow side of a roundabout, where motorists are likely to stop before entering the roundabout... but then that also means crossing an output side where motorists are least likely to stop.

The solution locally has been to add signaling crosswalks at a distance before and after the roundabouts.

But is it the case that someone empirically demostrated that making an intersection a roundabout or vice versa made matters worse for pedestrian safety?
From the small amount of research I did, there is insufficient evidence on the safety of roundabouts for pedestrians. There have been a few observational (before and after) studies that showed roundabouts to be safe for able-bodied adult pedestrians. But I couldn't find any studies for children and handicapped adults.


Well, if traffic never stops, but flows constantly, I could see where this might be an issue for pedestrians.

Locally small diameter roundabouts, along with narrowing the roadway, have been used to calm (slow down) high speed traffic. The traffic throughput has decreased slightly, but the speed of motor traffic has slowed dramatically. (motorists used to well exceed the 35MPH speed limit as they "raced" between stop signs) But the issue for pedestrians is that the motor traffic doesn't stop. Before, at stop signs, there was at least a time and place for peds to cross. As it is with the small roundabouts, the best place to cross now is at the input flow side of a roundabout, where motorists are likely to stop before entering the roundabout... but then that also means crossing an output side where motorists are least likely to stop.

The solution locally has been to add signaling crosswalks at a distance before and after the roundabouts.


Well written explanation of the potential problems. The solution of signalled crosswalks is most commonly mentioned. There are a couple problems with that, however:

Crosswalks are inconvenient for pedestrian use because people must walk over to the crossing, then walk back again to the sidewalk.
It's also difficult for blind people to even find the crosswalks, since they're not at their natural location as an extension of the sidewalk.
Signalled crosswalks negate the basic function of roundabouts (unimpeded flow through the intersection) because they require drivers to stop just prior to the intersection.
The signals only control cars entering the roundabout, exiting cars are not required to stop at the crosswalk--as genec said.
Again, for anybody who thinks roundabouts are not a problem for blind pedestrians, I invite you to navigate one on foot with your eyes closed. Report back to us...if you survive.