The issue is basically that gasoline and diesel consumption was used as a proxy for travel miles in order to pay for road maintenance and the scale used to relate miles to gallons is no longer accurate even for gas-powered cars (as average economy has improved). Obviously electric cars are an easy first target, since passing a tax increase is much harder than targeting a small group.
A Nissan Leaf weighs 3,291 pounds (source: http://www.nissanusa.com/electric-cars/leaf/versions-specs/). A GMC Yukon Denali weighs 5,491 pounds (source: http://www.gmc.com/yukon-denali-luxury-suv/features-specs/ca...), or 1.67 times more. It should do approximately 7.75 more damage to the roads it drives over than the Leaf will.
At an average of 15,000 per year, the Yukon owner getting 16 mpg (source: average of 14mpg city and 18mpg highway from http://www.gmc.com/yukon-denali-luxury-suv/features-specs/po...) will burn about 950 gallons of gas per year. At $0.563 per gallon tax (source: combined state and federal taxes from http://en.wikipedia.org/wiki/Fuel_taxes_in_the_United_States), that owner will pay about $550 per year in taxes.
If NC is being honest about their reasons for taxing electric vehicle owners, then the Yukon owner is being subsidized about $225 a year (should pay: $775, will pay: $550) for driving a more polluting, more damaging vehicle. That's assuming that electricity is completely untaxed in NC so that the Leaf driver is paying only that $100 tax.
TL;DR This isn't about fundraising. It's about protecting gas-burning vehicle markets.
Because I meant that it probably wasn't really going to stop very many people from buying electric cars (so it is then strange to assume it is about protecting the market for ICE cars).
Why not just have an income tax and sales tax, or maybe only one (I've heard arguments for both sides, but don't want to get into that debate) to cover all this?
It's the same thing with all the ridiculous fees governments charge for various things. For example, registering a vehicle at the DMV. Why does this cost anything? After all, your taxes already pay the salary of the person at the DMV, their office, etc. and the sales tax (in states that have it) paid on a vehicle purchase should take into account that the new owner will need to register it.
It's just a ridiculous way of "not really increasing" taxes.
Flat taxes with no exemptions eliminate armies of tax collectors, accountants and lawyers. They would eliminate a host of nickel-and-diming taxes.
A flat tax is beneficial to everyone but a politician who wants to punish one set of voters and reward another. So we get tax codes running to thousands of pages, millions of man-hours spent evading the rules and enforcing them, lobbyists spending all their waking hours trying to get their competitors taxed and their paymaster untaxed.
A fixed tax rate on the size of the economy and a fixed government size to match the tax rate would solve a million problems, but simplicity is like anti-matter to governments.
Another answer is that user fees are politically expedient, as you point out -- it's a way to increase government revenue without increasing taxes per se.
In any case, if you buy a car, the DMV fees ARE generally rolled into the purchase, though as a separate item. Not to be too pedantic, but you can always buy a vehicle and not register it -- for example, if you are from out of state and plan to register it in your home state, or if you need to do some work on it before you put it on the road.
Since it's not really practical to directly charge for road use (with the occasional toll road as an exception), taxes can serve as a decent substitute. Given that, it's good to line up the taxes with use.
That's very interesting. Is it possible that this could be part of the cause of the noticeably deteriorating state of roads these days?