Mobility is a very peculiar challenge for a city – different from health or education – because it’s one problem that tends to get worse as societies get richer. An advanced city is not one where poor residents use cars, but one where rich residents use public transport.
If all citizens are equal, then somebody who is walking or on a bike has a right to the same amount of road space as somebody in a Rolls-Royce or luxury car. And a bus with 150 passengers has a right to 150 times more road space than a car with one passenger.