Roundabouts are generally a good idea when it comes to easing traffic flow, as they eliminate traffic lights by keeping cars moving more often. They are not, however, great if you're the driver of a semi with a particularly oversize load. Depending on the length of the trailer, in fact, a roundabout may be a wildly difficult obstacle, requiring its own degree of special equipment.
In the US, the four-way-stop intersection is king, with little competition from roundabouts. In Europe, things are reversed, and the roundabout is much more common than four-way-stop intersections. While it has been said before that the roundabout is a more efficient way to handle traffic at a busy intersection, Mythbusters aims to find out the truth.
Roundabouts are the scourge of many a motorist and a favorite calming device of traffic engineers, and they're spreading like crazy across the United States roadscape. As anyone who's had the joy of driving in Massachusetts or New Jersey will tell you, plenty of drivers have absolutely no idea when to yield or how to successfully navigate these rings of macadam.