It wouldn't have to lock it. A simple warning LED located on the upper part of the door at eye-level that lights up and blinks when an oncoming cyclist from the rear is detected would prevent a lot of accidental injuries.
Jesus. A thing that warns you that you're about to injure another human being, and you're upset you might have to wait 2 seconds?
I hope that was sarcasm on your part...
I think their issue was not having control over when they leave the vehicle. If the locks are computer controlled, there's risk of a false alarm preventing your exit, potentially in an emergency.
I agree that this is better left to a warning indicator.
Yep, that's exactly my issue. Warning light is fine, lockout is not. Too many situations in which a lockout would be dangerous - false positives/failure of the system locking me into the car, carjackers taking advantage of it by parking a bike behind me, etc.