Charged for what you use? Tennessee Commissioner of Transportation Schroer proposing pay-per-mile idea.

The downside of fuel efficiency is that fuel tax revenues decline with increased efficiency, while wear and tear on the roads does not. Tennessee is predicting it will lose tens of millions of dollars over the next 10 years with more and more fuel-efficient cars on the road. As the Williamson Herald writes: Rather than bank on the revenue from the gas tax, levels of which have not been increased since 1989, [Commissioner Schroer] said he would rather see a system in place that generates revenue based on vehicle-miles traveled. With the popularity of the Nissan Leaf and other alternative modes of transportation that do not consume gasoline, the state is going to need to find other ways of generating revenue to pay for road projects. ‘We need to find a fair way to do it – pay for what you use, like a utility. In the long run, transportation funding will be bankrupt if we don’t do something.’”
Under the pay-for-what-you-use idea, drivers would be charged based on how many miles they drive times the weight of the vehicle. So the bigger the vehicle, the more you pay. More information is available here.