A new study out of the University of Arizona and two other national institutions recommends abolishing the gas tax.

Ashley Langer, with U of A, as well as economists for the Brooking Institute, and the University of Houston concluded the gas tax at the pump is outdated. Chiefly, because cars and trucks are smaller, consuming less gas, and driving further and longer on U.S. roads than ever before.

In their report for the Highway Trust Fund, they suggested a Vehicle Mileage Tax, VMT, could encourage motorists change their driving habits to reduce air pollution. The study also suggested a VMT would do a better job raising funds for road wear.

The current mileage tax has not followed inflation rates since 1993.