They're only confusing because there aren't any rules! A significant part of learning to drive in Britain is learning how to use roundabouts. In the US, they're just a donut-shaped free-for-all.
I agree, I drive both in the US and Ireland, and in Ireland once you know the rules of navigating a roundabout it's usually trivial to navigate all roundabouts. Just look at the 3 pics on this page:
http://www.drivingschoolireland.com/roundabouts.html
In the US (at least in the Boston area) it's another matter, and it's almost as if people just don't know what they're doing, and after doing my driving test here I'd believe it. :)
I should add that in Ireland there are still people who can't navigate roundabouts/traffic circles/rotaries, but I think due to the less dense population it's a bit less of a problem (except for some motorways around Dublin).
Definitely; I'm from the UK and just took my California driving test - it's amazing how simple it is! Didn't even have to reverse around any corners. Although I've never had to do that outside of my British driving test, either...
This seems like as good a forum as any... what exactly are the rules for two-lane roundabouts? From which lane is it okay to exit? If you're in the inner lane and want to exit onto the left lane of a four-lane road, do you have to watch out for people in the outer lane, or do they have to watch out for you?
I won't talk about left and right because I'll get confused.
If you want to exit after 90 degrees, outer lane. If you want to exit after 180 degrees (straight through), either lane. If you want to exit after 270 degress, inner lane at first, then start indicating you are exiting, perhaps moving to outer lane before exit. The latter sounds confusing, in practice it isn't, mainly because other people will be expecting it.
It didn't even occur to me that left and right lanes get confusing. My apologies.
My confusion about the multi-lane roundabout mostly stems from the scenario where two cars, entering from streets 90* in the direction of the flow apart, both want to go straight through. If the one entering 'upstream' takes the inner lane and the one 'downstream' takes the outer lane, it would seem that in some timing conditions you'd get a collision situation when the inner lane car tries to exit but must cross the outer lane to do so. Is this a practical concern? Is there a universal set order of precedence for this case, e.g. inner lane always yields if necessary?
You have the additional rule that everything gives way to traffic already on the roundabout, which (in practice) means that particular timing event doesn't occur. The downstream car cannot enter the roundabout until the upstream car has gone past, or it can enter only if the upstream car is too far upstream and is not a threat. In either case, there is no collision.
In places I've driven where there might be confusion, they mark the lanes with arrows to show which ones are exiting and when.
They work pretty seamlessly in my experience. You only have to look one way (upstream), instead of two, to judge whether to enter the intersection, and you don't have the time-waste of traffic lights.
It's a triple roundabout with a highway bridge separating two of them. The internals are arguably simpler but there are more entrances/exits than the magic roundabout.
For bonus points, check out what state this is in.
(I use Bing because last I checked Google still doesn't have a good satellite view of this, despite it being several years old now.)
I've been through that intersection! Let me tell you, coming off the highway expecting a normal intersection and getting dumped into that is pretty crazy. Not sure why they chose that design... Crazy MDOT.
If you sit down and try to draw the traffic light situation for that set of roads, this is actually a better solution than anything else I've been able to come up with. All the traffic-light situations I've mentally drawn out deadlock during rush hour with reasonable assumptions about people ending up in the middle of intersections accidentally as the light goes red, and have terrible throughput by comparison at all times of day. Presumably the actual civil engineers came to the same conclusion, only with better numbers and models. I can not imagine that was an easy sell, they must have had a rock-solid case.