[bryanlarsen]

The most relevant stat though is the number of miles of car usage. If there are ~20% the number of cars, but each car is used 10x as much, we're worse off. If nobody owns a car but always calls a cab, the cab might do twice as many miles deadheading to the pickup. And instead of lasting 15 years, a typical car might only last 2 years because it's getting 10x the milage per day. So fewer cars might result in more gridlock, noise and tire particulate pollution. Fewer cars might mean just as many cars built per year.