Vehicles, just like trains, cannot stop on a dime so the responsibility of safety falls on both parties regardless of "right of way". Talking about having a vehicle with more sensors doesn't really help if a driver doesn't have time to react to those sensors. Moving a step further, if you allow the vehicle to take control from a driver you add in more complications and danger for a whole host of reasons including 1) a driver reacting poorly to a vehicle taking control from them, 2) an auto driving system that is far, far from ready and could cause more issues, and more.
I truly think you could do a lot more to solve the issue by getting drivers and pedestrians to be more attentive around each other than any other sensor or signal.