Singapore also has a political framework that could force self-driving car adoption if the powers that be want it. Things that could be mandated such as self-driving only car lanes and motorways could be possible given the small size of Singapore and the powerful nature of the government. It would be unthinkable at present in America to force all cars on certain roads to be self-driving only. Singapore has the sort of culture that values "safety" over freedom.
In America, for better or worse, it would take a long time to mandate these things if they were even possible (considering that the same laws would need to be passed at least 52 times for states and territories). America has checks and balances--everybody gets their say.
In America, for better or worse, it would take a long time to mandate these things if they were even possible (considering that the same laws would need to be passed at least 52 times for states and territories). America has checks and balances--everybody gets their say.