COLLEGE PARK, Md. — Two East Coast states are about to test a vehicle miles traveled (VMT) tax, meant to either supplement or replace a gasoline tax.

The I-95 Corridor Coalition, an alliance of transportation agencies, toll authorities and public safety organizations for East Coast states from Maine to Florida, will begin testing a VMT tax in Delaware and Pennsylvania, reported WTOP. The VMT model levies a charge based on how many miles a person drives. A 2012 report conducted for the I-95 Corridor Coalition determined that the gas tax is unsustainable as a road-funding mechanism over the long term for East Coast states, and found the VMT model as “a primary candidate to replace or supplement motor fuel taxes” because it directly charges drivers who use the road.

On the West Coast, Oregon has been testing the VMT model for more than a decade in two separate pilot programs. Volunteers pay a 1.5-mile-per-gallon fee in lieu of the state’s gas tax. Mileage is determined either with a device installed in the participants’ vehicles or through a GPS-based system.

The I-95 Corridor Coalition project would include a three-month pilot in 2018 involving 50 vehicles in Delaware and Pennsylvania, according to program contractor CH2M Hill. In the process, the project would examine how to apply mileage fees on toll roads, how to calculate miles for out-of-state drivers and how to transfer payments from state to state.

The $1.16 million project is funded by a grant from the Federal Highway Administration, with drivers, state agencies, trucking and tolling groups providing feedback for the final report.

“We’re not endorsing this … but we want to make sure we explore it,” Patricia Hendren, executive director of the I-95 Corridor Coalition, College Park, Md., told WTOP.  Assuming the pilot is successful and the I-95 Corridor Coalition wins more grant money, a broader pilot could take place.

“A larger pilot gets into how we address pretty sticky issues, like privacy, technology and crossing state lines—basically what something like this would really look like in practice,” said Hendren.