While "human understanding" would be nice, detecting big solid obstacles is a solved problem. It just costs money. Until somebody orders enough LIDAR units to get the cost down.

Tesla's "autopilot" collisions are all very similar. They're all "hit big stationary obstacle that wasn't the rear end of a car". So far, a fire truck, a street sweeper, a stalled car at a freeway median, a crossing semitrailer, and two freeway barriers. This is a well-defined defect.