They do so already. There is a subsidy on leccy cars and there are taxes on petrol and diesel cars that are way in excess of the costs of roads etc.
The governments failure is that they not only believe in markets but they assume that markets left to themselves will solve the problem. So they do not have a strategy for the charging facilities which is the key to the issue. Most drivers couldnt care a damn how the car is powered - sexist maybe but I suspect many women dont have any interestin the technology at all. So if leccy cars are as cheap to run ( they currently are cheaper) and easy to refuel there is no issue.
