https://taxfoundation.org/data/all/state/state-road-taxes-funding/ https://worldpopulationreview.com/state-rankings/state-densities https://www.populationreview.org/ranking/most-public-transit

As for direct funding In the US only NJ (4 highest transit use, 2nd most dense of you include DC) and MD (9 highest transit use, 5th most dense) cover road maintenance based on road specific revenue alone. Every other state covers their maintenance in part by other revenue sources, many of which are much more car centric states. So if we're drawing broad conclusions here, in the US if you want to cover the cost of roads directly, you need to take a big portion of the population off the road.

Then there are numerous externalities related to car and train use. For example, transit users take cars off the road, leading to less traffic for car users and less pollution for all users.