No one is saying that people who use drugs (or alcohol, which you refer to) don't ever drive cars. My point was that the ones on the bus probably don't. People who ride the bus are disproportionately poor, and unable to afford a car.

As for your point about drunk driving, I would guess most people who drive drunk would be more likely to take an uber/cab than ride the bus, which is not point-to-point, and which often takes much longer.