An Uber style private hire vehicle does an estimated 10x trips per day as a private car in a city the size of London. An extra 100.000 taxis/ubers could take 1 million private cars off the streets. It seems like low hanging fruit to reduce traffic problems in large cities. My guess is that there are political reasons not to do it (taxi licensing is a source of money for many municipalities).

Dems: we need a police state because climate change. Reps: we need a police state because immigration. Is there a political option that does not involve a police state?