I hinted last week I would write about a peril from and to automatic cars, or actually any drive-by-wire cars.
That peril is they become highly useful terrorist weapons. Today terrorists get kamikazis to drive ordinary cars to attack targets and checkpoints. It will be easy to modify a drive-by-wire car (including the self-parking cars already on the market) to be controlled by the cheap remote controls found on toy cars and planes today, and easy to mount a wireless camera (X10, the terrorist's tool!) as well.
A remote control car can be a weapon on its own, just to smash into things, but more nastily it can be loaded with explosives or poison or other nasty things. If drive-by-wire cars become commonplace (and they will) this will be possible.
I present a problem without good solution, and I also fear some of the solutions even more than the problem. For example, one of the big advantages of the automatic self-parking car which I described earlier is the car that drops you off and picks you up right at the door of where you're going. However, just as false anti-terrorist security has made it almost impossible to park or pick people up at some airports, they will move to ban all vechicles from going just where we want them to go.
They may also start demanding government overrides for the automatic cars, so police can take control of our vehicles on demand, bypassing even manual control. They will try to tightly regulate the technology (stifling it) and only allow blessed companies to work on it. As I said, a problem without obvious solution.