The vision impaired and small children should not be driving anyway. And depending on the "handicap" and the age-related abilities they may also be detrimental to safe piloting of a vehicle. The solution is public transport. (Or tandem bicycles).
Except that one of the big upsides of autocars is this demographic of people. And many (most) places in the US are not conveniently served by public transit. Heck, I live in one of the better places (Portland Oregon) and even in the core of the city it's going to be easily 2x as long to take PT anywhere vs a private car. IMO the big promise of autocars is the potential for eliminating mass transit along with all it's annoyances.
They can ride as passengers. You're arguing that tandem bicycles is a serious solution for the elderly or handicapped people? Is there a community where this is common?