Comment by emporas

Well, why not then create bigger cars, or smaller buses? Between 5 people in a car or a 100 people in a bus, an optimal solution should be able to converge slowly, to 20 people in a vehicle. It would be different for every city, or region or country.

Most cars spend most of their time, being stationary in a parking lot or a garage, 93 percent of the time to be more specific, or 23 hours/day. Buses spend a lot less time being stationary. The trade off here is the speed of driving. Cars offer an unlimited amount of speed, while buses do not. An optimal economic solution should exist in which the economic actors, i.e. people will figure it out after a lot of trial n error.

A crucial factor in self driving cars no one mentioned, is the data the machine uses to drive should be incorruptible. A blockchain which supports billions of tps, offer a solution to that.

Additionally road variables change over time, and data should change as well. Economic actors, not just people should feed the machines with updated data every day. That means that a marketplace of information is required, in which the most efficient economic actors with the best accuracy and the best reputation are rewarded, and the worst economic actors, who's data aggregation cause a lot of crashes, fall off the market.

A marketplace of information, doesn't exist for the time being, so there is no chance for self driving cars to be safe and effective.