Most cars are parked by the roadside most of the time (constricting the cariageway). If most people who needed a car could just pick one up at their chosen dep

Most cars are parked by the roadside most of the time (constricting the cariageway). If most people who needed a car could just pick one up at their chosen departure point and abandon it at their destination, and if that were massively cheaper than private ownership (which it should be, because shared cars would see much greater utilization), that would slash the number of cars on the road. If these were self-driving, then presumably if the model you want doesn't happen to be at your departure point, you could just ask it to come to you.