How do existing self-driving cars handle this case? Perhaps regulation could cover this if the manufacturers aren't. The cars should have sensors to know it's not safe to open the door.
Getting rid of parked cars will be a good start.
EDIT: obviously the car can sound a warning or even briefly prevent the door from opening. Similar case, what if a car or truck is passing by very closely at that moment.
Given the sensors required to be self-driving, a self-driving car should be able to detect a bicycle in the "dooring zone", and prevent the door from opening and/or alert the car occupant.
Yes, proximity sensors are capable of dramatically improving safety for pedestrians and cyclists, even in non-self-driving vehicles.
Many categories of collisions caused by carelessness and blind spots could be prevented by automatically applying breaks, preventing doors opening, etc.
Actually, even current normal cars could easily give drivers and passengers that warning.
At least a rental Golf I was driving recently made all sorts of warning sounds about others coming to the proximity, not just driving close to something. For instance, a scooter passing closely (this was Paris) would make the dashboard whine.
Getting rid of parked cars will be a good start.
EDIT: obviously the car can sound a warning or even briefly prevent the door from opening. Similar case, what if a car or truck is passing by very closely at that moment.