Who is at fault if a parked car opens its door and a passing car hits it?

Many claims like this contain a percentage of fault, I would consult your claims department and they can determine it based on when the door was open.

Another View: The investigating officer would first determine whether the traffic-side door of the vehicle was opened or the curb-side was opened. If it was the traffic-side that was opened, it would be the fault of the person who opened the door, even if it wasn't driver who did it, the driver would receive the violation.