The episode of the Simpsons is on where they go to England. While driving around, Lisa is horrified that Homer has driven into a roundabout. They go 'round and 'round until they crash into the Queen.
How does one navigate through a roundabout? We used to have a “traffic circle” here, but it’s long gone and I don’t remember it very well (I was probably 5 or 6 at the time).
It’s pretty simple. Traffic flows around the roundabout in a clockwise direction. Traffic already in the roundabout has right of way over those cars waiting to enter the roundabout. When you drive up to the roundabout you look to your right and see whether it’s clear. If it is, then you enter and proceed around the roundabout until you reach your exit. If it’s not clear, you wait until it is before entering.
[size]Immediate caveat - left/right confusion will reign. You will understand how we feel reading ‘right-on-red’ rants…[/size]
You approach a roundabout. You reduce your speed, from 30 or 40, down to 10 or 15. You look right, because you give way to traffic from that direction. If there’s cars there, you stop and give way. If there’s nothing, you keep going. Once you’re on the roundabout, you have right-of-way, and so can happily carry on to your exit and your destination. You’re also supposed to indicate with left- & right-indicators, but many people don’t bother (cue petty rant).
Offical explanation
Much better on a four-way interchange than lights, assuming the land is available. A roundabout can’t break down, and functions in a power cut. It can cope with a sudden surge from a side road. They’re more pedestrian-friendly (and car-crahs friendly), not least due to their reducing all speeds - nobody hits anybody doing 40mph on a roundabout.
If you think of a roundabout like a small round 1 way road with several roads leading onto and off it with stop signs for the road leading onto the roundabout.
Now translating for left hand drive cars.
If you want to get onto the roundabout the stop sign means you need to stop and can then if the roundabout road is clear take a right onto the roundabout road and go anti-clockwise arround the roundabout until you can reach the exit you want. So cars on the roundabout have right of way and cars trying to get onto the roundabout must yield to cars allready on the roundabout.
Life gets more complex when the roundabout road is multi laned (though always one way only) or when multiple roundabouts are interconnected (avoid Swinden) or are partially controlled by traffic lights.
Roundabouts were my worst nightmare when learning to drive. Having passed (first time) I still dread them. The times I’ve approached them I am convinced the only reason I got past them was sheer luck.
Just to point out again that my post was translated to left hand drive vehicles. In UK roundabouts go clockwise and you make a left turn onto them.
Also if you miss the exit you want to take from the roundabout you do have to go all the way arround the roundabout until you can take the exit again.
Missing the exit is called being a wally in the English venicular, entering a roundabout without yielding to vehicles already on the roundabout is called being a f*cking dickhead.
You have to go in the left-hand lane if you’re going to turn left off the roundabout (usually the first exit). You must signal for this. The only time you don’t signal is if you’re going “straight on”, which you also do by going in the left hand lane around the roundabout, then out. You would however signal left just before taking the appropriate exit, so everybody knows you’re leaving, including cars waiting ahead of you to enter the roundabout. You signal right to turn right, or to go right round the roundabout and back up the road you approached on. Turning right is the most difficult manoeuvre, because you must do it in the right-hand lane - which means crossing the left hand lane to exit. There shouldn’t be anyone there, really, but there can be.
I’m doing roundabouts in my driving lessons right now. They’re not my favourite.
Lots of big roundabouts have more than two lanes. They’re even more confusing. Many of the biggest are traffic-light controlled, which makes things much easier. But plenty are not.
There are also mini-roundabouts on minor roads, which are usually just there to stop traffic going at ridiculous speeds. You don’t have to be quite so careful with those to stick to the right lane - just not driving straight across the white circle in the middle is enough. Still, the same rules apply, technically.
I am told I should always do roundabouts in second gear. In third gear it should be more or less doable. Main thing is to take good early observations, because cars behind will often assume you’re going to go for it, and if you then slam on your brakes, you’ve had it. There entrance to a roundabout is a standard give-way once you’re stopped.
Oh, hey, I forgot about the best of all: double roundabouts.
There are only a few of these around, and - imho - nobody understands them, not even traffic cops. Not even the people who invented them. It’s basically two roundabouts, but as you leave one, instead of moving onto a new road you are immediately on the next roundabout, which you have to negotiate as before. It can get confusing because they’re usually just marked with paint, and you don’t know which paint to follow. Also you have to look right twice, and because all the cars are moving about in relative proximity to you anyway, you may find yourself accidentally giving way to cars that aren’t on the roundabout you’re on.
Hope that clears it all up for you. Buses in the UK are cheap and “reliable”. I say grab yourself a zonecard and stuff the stupid roundabouts.
You’re working on that honourary island reputation, aren’t you? Admit it, you’ll face a double roundabout one of these days 
an old england roundabout is a new england rotary. they are a bit more scary in new england though.
Do you live in London, by any chance?
I’ve used them to perfom what what otherwise be called U-turns. The only reason I’m glad to drive a shite car.
Around here, you can spot people who don’t understand them - they aren’t local 
We have them here in the US, too, though not nearly as many. The differences are that traffic goes counterclockwise, they’re called traffic circles (at least in California), and I’ve never seen one with more than one lane.
No. Do they have lots of big stupid roundabouts there? That wouldn’t surprise me.
Alright, my assertion that “many of the biggest are traffic light controlled” should actually read “ONE of the biggest that Ross has seen is traffic light controlled, or maybe two, he can’t really remember, but it’s in Glasgow, anyway, which is pretty big, not as big as London, but that’s not my fault”.
There is one roundabout that I’m aware of in Long Beach, California. Apparently it’s proper name is Los Alamitos Circle, but I’ve never heard it called that. Normally it’s just “the Traffic Circle.”
Unlike what sounds like the case in the UK, this one has no painted lanes. It’s wide enough for probably four normal-sized lanes, but it’s completely devoid of markings. Here is an aerial photo, but the lack of lane markings isn’t terribly clear.
This is the only traffic circle that I’m aware of in this area, but there may be others somewhere.
If a traffic circle has more than one lane, then it isn’t a traffic circle. It is a Fiendish Thingie, designed to weed out the weak and stupid from the gene pool. If you are in the inside lane (because you are a) stupid, or b) a wanker) you could be there for years. No-one will yield, for they know you are weak. 
There is a multiple lane FT in Ontario, California.
I wish roundabouts AKA traffic circles were more common in the US. The post which suggest stopping before you enter defeats the whole point, however. Properly employeed, you yield (UK give way) to traffic already circling, Which usually will not require a complete stop…and that is one advantage. When two cars arrive at exactly the same time, from any direction, neither needs to stop completly. If they enter the circle at the same time, no collision will result, regardless of which direction they wish to leave the intersection. Essentially it creates an intersection equivilent to one with a 4-way stop, yet most of the time a “California stop”(slow and yeild, but not a complete stop if no traffic) is safe and perfectly leagle. Contrast this to the time-wasting standoffs that are common when two drivers ([pet peeve mode]who never seem to know right from left[/pet peeve mode]) arrive simultainiously at a 4 way stop.
In Australia, I observed these even on fairly minor residential roads…didn’t seem like they required much more land than a conventional intersection would have.
The classic mistake for those not familier with them is to make a 90 degree left turn. (assuming drive-on-the-right traffic) Making a leagle left turn requires a 270 degree turn to the right.
Hey, don’t worry Ross, I’ve seen those roundabouts too - there’s one just down the road from me in my little old town, and a huge big stupid roundabout with part-time traffic lights I am forced to navigate quite frequently in Milton Keynes.
Part-time traffic lights I ask you! Just asking for trouble. And you were saying lights make it easier?!
No, that’s not a rounadbout. A big roundabout is perhaps 100m diameter. We do occassionally have things like the one you linked to, and we we refer to them as ‘the junction from hell’. That’s their legal term, ask a lawyer.
Some time a while ago, I found a great link and posted it in a thread here, which explained the differences between Traffic Circles and Roundabouts. I’m busy googling…
Actually, re. the Long Beach one, yes it does seem to be a ‘true roundabout’, wiht what I can see of the markings on the road. It’s just so very strange to see a concentric arangement of streets around such a junction.
Pretty common, although not as standard as they are in the UK. The signage in the UK is about 10x better than you find anywhere in the US, and that helps a lot.
What’s really great about them is if you’re not sure of where to turn, just stay in the roundabout/rotary until you figure it out. 
There are lots of traffic circles in Washington, DC. The most complex one is Dupont Circle, just under a mile from the White House. It has ten “spokes” (Connecticut Ave NW, Massachusetts Ave NW, New Hampshire Ave NW, 19th St. NW, and P St. NW), but with two unusual additional features:
[ul]
[li]Through traffic on Connecticut Avenue can take a tunnel under Dupont Circle.[/li][li]Through traffic on Massachusetts Avenue can take an “inner circle” which only has entrances and exits for Mass. Ave.[/li][/ul]
The entire operation is controlled by stoplights, but it can get horribly clogged up. An aerial photo is here.
