Personally I don't find the old tired troupe of trying to separate tax payers in an attempt to further pit people against one another to be interesting at all. I find it futile and exhausting. The fact that car users pay a lot doesn't mean that they pay more proportionally to the costs that they're generating. Obviously there is a huge amount of revenue of all types (consumer spending, taxation, government revenue etc.) associated with car culture because it is so pervasive and because, frankly, it requires a huge amount of money to be spent since it is such a costly form of transportation in every aspect. The fact that streets need to be wider, huge amounts of land need to be devoted to vehicular storage, density is lower requiring everyone to travel greater distances, increased drainage infrastructure is needed to deal with the run off from all the non-permeable surfaces etc. means that all the costs associated with it are difficult to quantify. However, all the attempts I've seen to measures it show that active transportation has by far the lowest fiscal burden so, getting mired in such minutiae is mostly irrelevant and simply leads to unproductive bickering. After all, if we were to increase taxes or other fees, it wouldn't make sense to do so for the sake of the least costly transportation methods if the intention is to find real solutions rather than to sabotage. It's simply a great way to divert the conversation and make it seem as if active transportation is an expensive burden when in reality the reverse is true. It's an inexpensive relief compared to the expensive burden of the status quo.
The more interesting question is what is the best way to allocate the limited revenues that we already have? Since there is very little appetite for increased taxes - especially given the looming economic malaise - so how can we use the funds we have to transport the most people with the fewest negative affects on the environment and the quality of life in our communities?