[jabl]

I fully agree reducing CO2 emissions should have a high priority. Which for fossil fuels would mean a quite substantial tax on the fuel volume, but for EV's it's trickier since electricity is used for many other things, and electricity production is already taxed for CO2 emissions (or cap and trade etc). There's no particular reason, from an emissions perspective at least, why electricity for EV's should be taxed higher than, say, for domestic use. If anything, an extra tax on electricity could be counter-productive if it causes more people to prefer ICE cars.

Which implies that a vehicle tax should then be primarily concerned with non energy use types of externalities. And maybe generally funding road construction, and so on. Probably a lot of that is more accurate if the tax is a function of distance driven than a fixed cost, true, assuming you can reliably get that information in a privacy compatible way.