Obviously yes, but people still drive drunk and speed in places with reliable public transit. Not to mention that the type of drunk to think that vehicular manslaughter is acceptable will also probably be a bit shit to ride with.
You can't do that much damage in a train car versus behind the wheel. That said angry drunks and rude assholes can have a little bit of prison time as a treat. In all seriousness, if there is reliable public transport, then they should get their license taken away. At this point i mostly drink at home, and the few times we go out, we uber to and from.