After the shock of the recent fatal crash of a Metro-North train in New York (Wikipedia) wore off I began to wonder… Google and BMW are very close to creating practical self-driving cars (see recent New Yorker article and one in Technology Review). Why aren’t trains, which operate in a much more structured environment and whose capital cost per vehicle is much higher, already self-driving?
Separately, when my American friends hear about a train crash or a building failure in China they use that as more evidence that something is fundamentally wrong with the Chinese social and political system. But when a train derails in the U.S., that is just bad luck and not a reflection on anything having to do with America or the U.S. social/political system.
And finally, though not related to trains, the above articles make me wonder what happens when most of the cars on a highway are self-driving. Each car is putting out a huge quantity of signals via laser, radar, and ultrasound and depending on getting clear returns. This seems easier when there is only one self-driving car on a given highway. What happens when signals from different cars collide?