His impact will be essentially zero if he's a responsible defensive driver. I've had a license for 30+ years, have driven millions of miles, and have never, not once, been at fault in an accident.
Even so, there are still ways that it can make streets more hazardous for others. For example it's pretty hard to see around big vehicles, sadly.
This is true. But from a moral standpoint, I have to deal with the fact that anyone has the ability to ingest alcohol and get behind the wheel of a car, and there is nothing I can do about that. So others just will have to wait a bit to see around my big truck. Thats the social contract we are making.