This is more or less a completely imagined issue. The most dangerous form of transportation is personal vehicles, and its not even close.
For example, on the NY subway you have a 100x greater chance of dying by driving instead of taking the subway. 100x.
If you look at the risk of injury it's not any better.
The thing is that feeling unsafe and actually being unsafe are two different things. Cars feel safe because you're isolated, you have walls between you and everyone else. Public transit feels unsafe because you can directly see other people and there's nothing stopping them from just walking up to you.
Like, for your point on drugs, on a subway you can literally see the people on drugs, which makes you feel unsafe. In a car, you don't know who is on drugs, so you feel more safe. But, you're not. People are still on drugs, but now, they're also operating a deadly weapon.