The roads are public space. That's why you can walk on them, ride bikes on them, have protests on them, parades, farmers' markets, etc. Since they are public I don't think that one user group should pay taxes in any way that makes them feel ownership over this public space.

The taxes should make them feel sorry for the abuse they do to the public space. The wear and tear from heavy vehicles (why oh why don't they charge DMV fees on the weight of your vehicle instead of the "value"???) The noise and pollution. The damage to the environment from the toxic chemicals they use and spew.