> But when cities are much bigger, problems start to arise.

Actually, the bigger the city, the more efficient public transportation is. Just look at LA with it's 16 lanes of car traffic, and compare it to London - the fundamental difference being that LA has no real public transport and London has an extensive tube and train network. Oh, and London has about twice as many people as LA... which one would you rather be a commuter in?

Just an example: a colleague of mine was commuting from Reading to Canary Wharf (before the Elizabeth line even), this is now an hour long train ride, if you tried to take it by car it would be double that - and then you'd have to find parking for your car in Canary Wharf, which is not easy and very expensive.