Things can change.
Didn't used to be robot murder cars on the road either.
Maybe crossbows, aim at the tires? Sorry: tyres.
Maybe some kind of light that is extremely bright in a particular wavelength, that blinds their cameras and sends them into an emergency halt mode?
But anyway lol, sawed off shotguns are extremely illegal in all the US as well... I guess the analogy was lost in translation =P