Embodiments are described of an apparatus including a computer with a user interface. One or more door clearance detection (DCD) sensors are communicatively coupled to the computer and adapted to be mounted to an exterior of a vehicle door. Each vehicle door has a door impact zone such that an object in the impact zone would be struck by the door if opened, and each DCD sensor has a field of view and a range that establish a detection zone within which the DCD sensor can collect data. Each detection zone includes at least the corresponding door impact zone. Logic stored in the memory or storage includes instructions that, when executed by the processor, cause the processor to receive data from the one or more DCD sensors; determine whether there are objects in the corresponding door impact zone; and warn vehicle occupants if there are objects in the impact zones.