[Blarg]

If I understand how roundabouts work correctly, they seem inherently quicker. At traffic lights there is always the possibility to have cars backed up at this side or that while there are no cars at all to go through the other way. So non-productivity is pretty much built into the system. Traffic lights are also sometimes very badly timed one to the next, so a car can't travel at speed even as long as a block. There are a million ways for traffic lights to be wasteful even if everyone were a perfect driver.

I think roundabouts might be at their best where people are known to be a little more courteous, just a guess. For instance, in Los Angeles, most people are horrible drivers, reflecting the general egotism and aggressive obliviousness of the place, and if we were to switch to all roundabouts tomorrow, there would be a huge rough adaptation as people began to actually pay attention to their driving and not do it purely mechanically and absent-mindedly. Letting people in your lane is regarded as a dangerous and humiliating admission of inferiority in Los Angeles, so the cooperation to keep a roundabout from completely gumming up would probably rare at first. I can picture the annual freeway shooting season turning from an occasional pleasant pastime into something truly worrisome.