An economist takes a look at existing law and argues driverless cars are probably legal:

Over at the blog Marginal Revolution, economist Tyler Cowen points to a recent research paper by Bryant Walker Smith, a fellow at Stanford Law School, who has made the legality of driverless cars his bailiwick. In offering “the most comprehensive discussion to date of  whether so-called automated, autonomous, self-driving, or driverless vehicles can be  lawfully sold and used on public roads in the United States,” Smith argues that driverless cars are “probably legal.” He concludes [PDF]:

Current law probably does not prohibit  automated vehicles — but may nonetheless discourage their introduction or complicate their operation.

Unlike many journalists and policy-makers, Smith begins his analysis with a presumption of legality instead of illegality. “Until legislators, regulators, or judges definitively clarify the legal status of automated vehicles, any answer is necessarily a guess,” he writes. Smith’s own guess turns on three “key legal regimes”: the 1949 Geneva Convention on Road Traffic, National Highway Traffic Safety Administration regulations, and vehicle codes in the 50 U.S. states.

Smith doesn’t think that any of these regimes expressly prohibits driverless cars. The Geneva Convention says a driver must be able to control a vehicle at all times, but that stipulation is probably satisfied if a human can override the automatic operation. N.H.T.S.A. rules don’t explicitly rule out driverless cars either — though an odd rule saying hazard lights must be “driver controlled” might be a sticking point.

States codes, meanwhile, “probably do not prohibit” driverless cars in Smith’s mind, but they do complicate the situation. Right now these codes all naturally presume the presence of a human driver; in New York, for instance, there’s a rule that drivers must keep one hand on the wheel at all times (who knew?) that could become a problem in an automated-vehicle world. Additionally, laws dictating a certain following distance might interfere with algorithms that keep driverless cars close together on the road.

Sounds like an interesting loophole – why worry about whether it is legal when you can instead ask whether it is illegal? I still think a lot of the issue with driverless cars comes down to people, both “drivers” (now people who can override the car’s autopilot when they want) and other people on the road around the driverless cars, adjusting to the change. If it is like other modern technologies, like smartphones, and drivers realize they might be able to do other things while driving, perhaps the switch may be quick.

Another thought: could driverless cars and electric cars end up prolonging and even extending urban sprawl? If commuting is easier and consumes fewer resources (still debatable considering what it takes to produce batteries), why not continue it?