The potential problem with the current tax on fuel to fund road maintenance in that a driver's fair share of road maintenance may not correspond to the amount of fuel she consumes. This can be unfair. For example, Bill Gates, who can afford to drive a $100,000 Tesla electric car, may drive a around a lot and wear out the road much more than a poor person who commutes in an old, cheap gas guzzler. Yet because road maintenance is allocated by the gas tax, Bill Gates, whose electric car consumes no gas, would pay nothing for road maintenance, while the poor person with the gas guzzler would pay too much.