[kstenerud]

The generic "city" is not a very useful term here. How many people are there? There's a big difference between New York and Maza. What is the topography like? Is it sprawling like Phoenix? Or dense like Tokyo? How much density, population, and infrastructure is required to make a convenient and economical transit system? I'd wager far too much to displace cars in any meaningful way except in the largest cities.

Cars are used because they are versatile. Every other form of transport has far more narrow use cases.