Well, we have had a couple such accidents with tourists driving on the wrong side of the road. 
But, yes, in general there are many fewer head-on collisions at roundabouts than at traffic lights.
For the most part, those aren’t roundabouts.
All the rotaries I go through regularly here in the Boston metro area meet that article’s criteria for a roundabout.
This database is a bit out of date, but it has only 3 roundabouts for the entire state of Massachusetts, but 23 rotaries. They consider them to be different things. However, perhaps the rotaries have been upgraded recently. Do you have any pictures of them? Perhaps they have Wiki pages?
For what it’s worth, two of the most common types of collision over here happen on roundabouts:
A driver is in the outer lane intending to take the second exit and a driver on an inside lane cuts across to use the first exit and clips the front of the other car. This is most likely when a driver is unsure of which exit he wants and is reading the signs. He gets clipped by an impatient local.
A driver is stationary and second in a queue to enter a roundabout. He is looking for a gap in the traffic as he hopes to follow the first car in. He sees a gap and pulls away assuming the first car will too. The first driver is more cautious (chicken) and stays where he is and gets rear ended.
There are a couple of two-lane rotaries in Augusta (they aren’t really up to the “modern roundabout” spec, but they function more or less the same way), and I know a few people that have rear ended another car that didn’t move off when they thought it would.
I don’t think we have too many people in the left lane cutting people off. Rather, what we do have are certain drivers that are diametrically opposed to ever using the left lane—ever—no matter which exit they are going off. They also never seem to bother to signal left when they’re going to be crossing over a lane to stay on the circle, so it can be an unexpected and unpleasant surprise if you happen to be in the left lane intending to go straight. :mad:
That database doesn’t seem to list any of the ones I go through every week, as any type.
All are in Cambridge, Medford and Arlington, and none seem to be listed in that db. I’d say that db is very incomplete.
One possible factor in favor of traffic lights over roundabouts is that, in a well-designed system, red lights aren’t as common as green lights. If the lights are synchronized well, you’ll probably be able to get several green lights in a row for each red light, and it gets even better for intersections where one road gets a lot more traffic than the other.
Of course, this depends on how many other intersections are controlled by lights, so it’s possible to get a bistable situation, where turning a light into a roundabout would be bad in a mostly-light town, but turning a roundabout into a light would also be bad, in a mostly-roundabout town.
When they widened the main drag in my town they installed a number of roundabouts. People hate them with a passion, but that’s because they are either: young, and don’t like not being able to bomb down the boulevard at reckless speeds, or old and too pig-ignorant to learn a new way of driving. If they hadn’t installed concrete planters in the center of the things I think old farts would just ignore the circle and drive straight through.
But there has already been a drastic decrease in serious accidents on that street.
they’re starting to show up in my area along with “continuous flow” intersections which are not continuous flow.
Recently I came across2 roundabouts (or circles?) at night that were stacked next to each other and the effect was unnerving. We were making our way around road construction trying to get back to the highway by driving a grid pattern. It felt like we drove onto a roller coaster. They will take some getting use to but if they move traffic faster then I’m all for them. I’d prefer driving down a road with timed lights but that’s just me. I like things to be consistent on the road.
I don’t like the design of the roundabout for Cemetery and Main. It’s not clear to me who has right-of-way when the inner and outer lanes cross. Zoom in, and look at the maroon car heading north on Main, and the silver car about to enter heading west on Cemetery. If maroon wants to keep heading North, and silver is a little slow, they could collide, and it’s not clear (to me) who would be at fault. Silver is staying in his lane, but maroon is staying left of the dashed line.
The other roundabout doesn’t have that issue, since the outer lane isn’t continuous.
Assuming the rules are the same as in the UK, traffic already on the roundabout has priority. If silver crosses the give-way line into the path of a car approaching from the left (in either lane) he’s at fault.
Silver has a yield sign. The person with the yield sign doesn’t have the right of way; which lane he is in is irrelevant.
Think about a four-way intersection of two one-way streets (essentially what you have at that spot). The road you’re on has a yield sign, and you want to go straight across. Are you not going to yield to traffic in every lane that you will be crossing?
Just on this point, Mythbusters tested roundabouts vs a 4 way stop. American drivers managed just fine with the roundabout after only a short practice. And the roundabout was more efficient, even though the drivers were more familiar with 4 way stops.
That was for a single lane intersection, but I think it’s enough to put to rest the idea that American drivers can’t handle roundabouts.
Yep, silver yields, no question. If he crosses the give way line when there’s oncoming traffic and collides with maroon, it’s silver’s fault.
The way it looks to me, silver has to yield to the outer lane, but then enters and stays in that outer lane. Maroon is in the inner lane, and crosses the outer lane to exit.
If I just entered the right lane on a freeway, and there is a car in the left lane, he can’t cross into my lane to exit unless it’s clear. It’s counter-intuitive for the roundabout to behave that way.
I believe this should answer your question quite clearly. Silver has a yield sign, underneath it is a sign that says “to both lanes in roundabout.”
The striping on the roundabout in question indicates that the entering car is the one crossing lanes, not the exiting car.
Fair enough. Maybe it’s more obvious when you drive it that it’s more like crossing a road than entering a freeway. None of the ones near me have two lane each way from four different directions like that.
I’m still not exactly sure why I didn’t like it or found it confusing. Maybe it was the surprise of it. I’m sure time will improve how I feel about them but right now they make me uncomfortable and that’s directly proportional to the amount of traffic on them.
http://www.frcog.org/pubs/transportation/Roundabouts/Roundabout_FAQ_FINAL.pdf
This doc from here in the suburbs seems to suggest that Fresh Pond is a rotary but not a roundabout…