[quonn]

You can slap a tax on the car. You simply take energy used/miles driven and that's your multiplier for a yearly vehicle tax. It could be collected by insurance companies (that usually require you to submit the miles driven anyway) on behalf of the government .

As for the other things, such as congestion, I believe it when I see proof that there is a big difference between cars. Even if there is, the priority right now should be energy efficiency, because reducing CO2 emissions is fairly urgent.

[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.