It could be worse, you could have variable toll bridge crossing and toll lanes that can often go > $10 like Seattle/Bellevue area.
The system needs a significant change overall, imo,
It would be interesting to see if they could remove state road tax on fuel and have some factor of pay per mile, e.g. Unit cost * Distance * (Weight / number of wheels) * (Tested Emissions output or Zero Emmisions Factor)
Trucks would likely need some rebate to balance to ~equal today, though that could be tied to the inverse of number of violations (over weight, time overage, emissions, etc)
Of course this would impact gas-guzzling SUVs, Pickups and RVs the worst, so maybe this is just a crazy idea though!? ;-)
This can get complicated quickly if put on the annual tabs/road tax, e.g. From the U.K.
Print Vehicle tax rates - GOV.UK