Many people in larger cities do quite well without cars. In Manhattan, it's quite normal even for the hedge-fund-managing class to take the subway.
Knowing that it's possible to comfortably get around the city without a car, these citizen can't help but notice how much their quality of life is lessened by people insisting on cars.
- Emissions, known to cause premature death, and often exceeding the guidelines, especially in summer
- Traffic accidents
- About 2/3 of the area of public streets being required for cars (two pedestrian walkways, two lanes parking, two lanes traffic)
Even without completely eliminating cars and trucks, which you would probably still need for deliveries, emergency services and disabled people, you could reduce most roads to one lane, and get rid of traffic signals. That would:
- Greatly increase the speed of biking (currently, 1/2 of the time is spent waiting for signals or in traffic)
- Increase the speed of busses even more (they spend more time waiting in traffic that bikes can pass)
- More than double the available space for wider sidewalks, greenery etc.