However, I don't think Washington's approach is appropriate. There shouldn't be a flat-tax for EVs. Taxes that go toward transportation infrastructure upkeep should be usage-based since the more a vehicle uses roads and bridges, the more wear and tear it causes. Similarly heavier vehicles cause more damage. Vehicles that consume liquid fuels pay a per gallon tax. The more they are driven and the heavier they are, the more fuel they use and thus they pay more tax.

Secondly, why are plug-in hybrids (either power-split like Ford or Toyota or series like the Volt) exempted? In theory, these vehicles pay tax based on the fuel they will inevitably use. However, many of these vehicles, especially Volts use almost no fuel and will pay a disproportionately low amount of tax.  Like pure BEVs, these should pay a mileage/weight based tax although perhaps at a lower rate in proportion to their EV driving range. 

My guess is that politicians opted not to go the mileage based route for plug-ins over privacy concerns because drivers don't want to be tracked. However, if road taxes are to be fair, they should be levied in proportion to use and this is not the way to do it. 

Reshared post from +Green Car Reports

What do you think of Washington's new flat tax rate for electric cars… and its exemption for cars like the Chevy Volt and Prius Plug-In?