The government's auditor says Congress should institute a pilot program to test raising money for road repairs through a tax on vehicle miles traveled.
Congress and the Obama administration have struggled to find new revenue to pay for maintaining the nation's roads, as gas tax revenue fails to keep up with repairs.
Over the coming decade, the federal government faces a $110 billion shortfall for road repairs without new revenue, something that will get worse as government fuel efficiency mandates rise and reduce fuel use.
The Government Accountability Office thinks a mileage-based user fee — known as a "VMT" — should be reviewed by Congress.
"Without a federal pilot program to evaluate options to more accurately charge commercial trucks and electric vehicles for their road use and the costs and benefits of such systems, Congress lacks critical information to assess whether mileage fees for these vehicles could be a viable and cost-effective tool to help address the nation's surface transportation funding challenges," the GAO said.