It actually is! It's a statistic that is tracked by the Census. It turns out, that the majority of road maintenance is paid directly by user fees: https://taxfoundation.org/data/all/state/state-infrastructur...
> If we are going to talk about how much the cost of public transportation such as trains or buses are covered by taxes it would only be fair to look at roads and personal vehicles too.
Absolutely! I agree that we should be pricing pollution and other negative externalities. But in addition, we should fairly price the all public services. And people who need public assistance should just get money.
And of course, we should be penalizing density pollution. There's no reason to build high-rise offices, and we should be demolishing them by now (except for historically-significant buildings).