DALLAS -- Massachusetts Gov. Charlie Baker used a line-item veto Wednesday to kill a provision in the state's new highway funding bill that would have set up a pilot program for testing a vehicle-miles-traveled road fee system.

Baker carved the provision out of a highway infrastructure bill (H. 4424) signed into law that authorizes $750 million of state road bonds supported by Massachusetts' annual federal transportation funding and creates a new $50 million state grant program to help local governments maintain small municipal bridges.

The highway measure passed the state House unanimously, 158-0, and with a single dissenting vote in the Senate, 38-1, on the final day of the session.

The vetoed provision directed state transportation officials to apply for funding from the Federal Highway Administration for a pilot VMT effort. The new federal grant program was created by the five-year Fixing America's Surface Transportation (FAST) Act.

The highway law provides $95 million of grants over five years to states for testing alternatives to the gasoline tax to help sustain the federal Highway Trust Fund. The first $15 million of the grants are to be awarded soon.

Massachusetts' pilot effort would have been limited to 500 motorists who would volunteer to pay a per-mile fee rather than the state's fuel tax of 26.5 cents per gallon.

The VMT proposal would be a burden for motorists in rural western Massachusetts, said Baker, a Republican.

"I would never support a vehicle-miles-traveled tax unless I was absolutely sure it was not going to create an additional burden on drivers, especially on drivers in parts of the commonwealth where there's not a lot of available public transportation," he said.

The state gasoline tax is a fairer way to pay for roads than a VMT because it rewards drivers of fuel-efficient vehicles, Baker said.

Baker also said that Massachusetts should not set up a pilot VMT program until results are available from similar efforts in Oregon and California.

"Let's see what we can learn from the folks who are doing this in other states," Baker said. "There are already a bunch of states that are doing experiments on this. We can certainly learn from those experiments."

California's nine-month pilot VMT test began July 1 with a goal of 5,000 participants. Oregon has a fully function VMT program that began in 2015 with more than 1,200 vehicles now enrolled. Motorists in the Oregon program pay a road fee of 1.5 cents per mile in lieu of the state gasoline tax.

Members of the Interstate 95 Corridor Coalition are seeking a $1.5 million VMT grant from FHWA for a mileage fee pilot program in Delaware, Connecticut, New Hampshire, Pennsylvania, and Vermont.

Massachusetts Senate president Stan Rosenberg, a Democrat from Amherst, said he was disappointed by Baker's VMT veto.

"The gas tax is going to be a declining revenue source over time as vehicles become more and more efficient, and yet we will still have roads and bridges to maintain," he said. "Eventually we're going to have to transition to a different form of revenue, and we need to start wrestling with that."

States are looking at VMTs because gasoline and diesel taxes are losing their effectiveness as the prime source of highway funding with more fuel-efficient vehicles on the road, said Joshua Ostroff, interim director of the advocacy group Transportation for Massachusetts.

"As the gas tax revenue is flat and with the trends towards more fuel-efficient vehicles, [we see] that we need to be exploring alternative technologies," Ostroff said. "The state needs to find a way to maintain transportation funding and fairly charge road users."