Technology and automotive companies touting self-driving cars as the future of transportation may have some work to convince San Franciscans, who keep attacking the vehicles. A third of traffic collisions involving autonomous vehicles in 2018 so far featured humans physically confronting the cars, according to data released by California. In one case, a taxi driver exited his cab and slapped the front passenger window of a General Motors Cruise parked behind him. No one was hurt, though the car sustained a scratch. In another case, a pedestrian hurtled across an intersection despite a "do not walk" sign, shouting as he went, and rammed his body into a different Cruise's rear bumper.