several states (HI, CA, OR off the top of my head) have trialed mileage-based fees. The problem becomes convincing anyone there's political credit to be gained

several states (HI, CA, OR off the top of my head) have trialed mileage-based fees. The problem becomes convincing anyone there's political credit to be gained by implementing/overhauling those systems. I suspect it will take as-long-as-it-possibly-can for those and bureaucratic reasons (contracts/pilots/implementation of those systems).