My question was not whether the robot car could win in court. My question was, how will they know to pull over? I guarantee you that at some point in some radar trap town, there will be a cop who wants to pull them over. And if sirens can make them pull over on a desolate roadway somewhere, that would be a real cool way to hijack an expensive shipment of electronics.
Ah, sorry. The answer to that is even simpler. If the camera can see a traffic light several hundred yards away, it probably can see bright blue and red flashes ten yards behind. The pattern is unique, and it's trivial for a computer to figure out. (By the way, the same applies to other emergency vehicles.)
And if sirens can make them pull over on a desolate roadway somewhere, that would be a real cool way to hijack an expensive shipment of electronics.
You don't need a siren. Just park your own car across the road. The robot vehicle will stop. It will not make a U-turn and run away. However... this very method also applies to human-driven vehicles. I heard that gangs in Florida did this. The vast majority of drivers will not escape this trap - and those who escape are probably too dangerous as victims anyway. The criminals do not need a 100% result.
IMO, a gang that stops vehicles and steals stuff is not overly concerned about health and safety of the driver. If there is a human in the vehicle, he will be killed, or knocked out and left in a ditch. Perhaps there are gangs who are not willing to kill but willing to steal... but the robot will "dial 911" in its own way, and the thieves will be racing against time to unload that trailer without forklifts or a dock. If they simply steal the whole rig, they will be tracked by radio - the trailer is too large, and it offers many places for concealement of a small cell phone.