Running into the back of a police cruiser that's partly in the lane with lights on is something humans generally only do before blowing a .1x on the breathalyzer.

The link you posted shows a clear correlation between low light conditions and hitting people on the shoulder. A police cruiser has blue lights and presumable the federally mandated reflective surfaces that all vehicles sold in the US have (usually in the tail lights).

This is a typical case of software making stupid mistakes a human would never make.