Cars are not the problem. People are. 95% of drivers shouldn't even have a license. Just bump up the requirements until only 5% of people attain driving license.
Or, or instead of your crazy idea, we could update our cities so that cars aren't required and I suspect people might just choose to save on car payments, insurance payments, registration fees, gas/electricity, inconvenience of parking, wasting hours on daily commutes, etc, etc...