within 5 years, the first (partially) self-driving cars will become available.
Partially self-driving cars are already common: Cruise control, ABS, traction control, parallel parking assist, lane assist, auto-braking etc.
I would expect rich people to be better informed and more likely to let others take the risk of the early technology.
I would expect the poorer countries to be more likely to allow the risk especially countries that already have atrocious road safety records - it would be easier for these vehicles to be safer than the bad drivers.
requires predicting when the majority of the world will become "developed", which may very well be never.
"developed" is an ever moving target, the poor people in developing countries already have technologies that we didn't have 50 years ago. And it is often the west that prevents countries from developing by controlling banking and allowing futures contracts.