Will autonomous taxis decrease the number of vehicles on the road? Unlikely as you still need almost as many vehicles in peak hours and cheaper taxis mean more people switching from public transport meaning more taxis.

What we really need to do is clear city streets of private vehicles and taxis and return them to cyclists and pedestrians. Our cities really need more efficient transport like light rail , busses and, the real gamechanger, hyperloop, operating underground and above the streets on elevated roadways, tracks and tubes to move people fast and efficiently around the city, between cities and from the suburbs.