Right. Looked at a different way, self-driving cars increase the utility provided by cars, so -- since people will only buy self-driving cars if the price premium over non-self-driving cars is less than the added utility -- can be expected, <i>all other things being equal</i>, to increase the number of cars sold and in use.<p>OTOH, because self-driving cars decrease the number of cars needed in society to deliver a given degree of utility, they could facilitate a reduction in the number of cars, <i>but</i> some other changes would need to occur to realize that reduction. Tax, regulatory, and&#x2F;or urban design policies which disfavor individual ownership of vehicles in favor of centralized on-call services would have to reduce the number of cars on the road.