Mileage-based user fees (MBUF) are an alternative way to finance the construction and maintenance of roads. Rather than the current gas tax method, which is based on the amount of fuel purchased at the pump, a VMT tax is based on how many miles are driven. A mileage-based user fee system has been proposed in the United States and elsewhere in the World as an infrastructure funding mechanism to replace the gas tax.
Since 2000, gas tax revenues have declined significantly as a result of less driving, increasing fuel efficiency and decreasing purchasing power. As such, we are only investing about 40 percent of what is necessary to meet the needs of surface transportation infrastructure at all levels of government.
As gas tax revenues dwindle, policymakers in the U.S. have had to divert billions from the general fund and other non-transportation funds to pay for infrastructure. This is increasing pressure on transportation policy makers to search for new, viable road financing mechanisms.