The American transportation industry has been calling for national rules governing self-driving cars, and it looks like it might get its wish. Senators Bill Nelson, Gary Peters and John Thune have unveiled the principles they'll use to craft legislation that greenlights autonomous vehicles. Safety will be the top priority, they say, but they also want make sure the law is "tech neutral," clears up the roles of federal and state governments and improves cars' online security. And importantly, they want to "reduce existing roadblocks" in the law -- after all, many laws assume that someone needs to take the wheel.