Earlier quoted context omitted.
I've been talking about this for years with friends. I bet on Singapore. (I lived there 2.5 years and know the place a bit).
Do you need a car in Singapore? I thought they had decent public transit?
* Severe congestion pricing
* Expensive due to severe taxes (generally over 100k USD)
* Licensing for a car is time-limited. I think this is about 10 years or so.
The last point in particular makes it feasible to cycle out the entire country's cars in a relatively short time.
EDIT: Add more newlines between bullets