"and not spend the extra money to try to weigh exactly who is causing the most wear and bill them separately." To the contrary - that's a good reason to subsid

"and not spend the extra money to try to weigh exactly who is causing the most wear and bill them separately." To the contrary - that's a good reason to subsidize the construction of of infrastructure, but having some sort of incentive to use less damaging forms where possible makes all kind of sense. Part of the reason for the stupid-sizing of consumer vehicles in the US over the last decades is because the incentives are all messed up.