In New Zealand, we pay a petrol excise duty which helps pay for the roads and traffic accidents. No such duty is charged on diesel, instead you pay per kilometre, depending on how much your vehicle weighs. The law is written such that any vehicle consuming fuel not taxed at source must pay road user charges. Since electric vehicles consume electricity which isn't taxed, they must pay road user charges. The per kilometre charges on my vehicle are more than the cost of the electricity.
This is changing, starting in October electric vehicles will be exempt. The exemption will expire in 2013, which is probably a good thing -- if electric cars take off, there would be a big hole in the ACC & Roading budgets. It would seem that we need to thank Hon. Dr. Nick Smith, MP for Nelson and owner of a Hyundai Electron.