This brings up a point I've thought about quite a bit with autonomous vehicles. I studied transportation planning in college and one of the tenants is that human drivers are on a spectrum between aggressive and conservative about finding efficiencies in high traffic situations. The canonical example is that if a lane next to you is going significantly faster, an aggressive driver will perform a (relatively) unsafe maneuver to cut off drivers in the faster lane and change lanes.

IIRC, significant research has been performed to identify whether the resulting lane change is net positive (frees space in the slower lane) or net negative (causes cut off car to slow down).

If autonomous vehicles prioritize safety over efficiency by stopping if there's an ambiguous intersection, will that have a net negative effect on traffic while all these self-driving cars slow down for each other.