Oregon's experiment with a mileage tax using GPS technology is over, but the legislature now wants to study a congestion tax.

A $10 million budget request to take the next step on the mileage tax study did not survive the legislative budgeting process, says Chris Warner, the governor's senior transportation adviser.

But the 2009 legislature removed a sunset clause from the statute authorizing the Road User Fee Task Force that studied the mileage tax, and the task force now "exists in perpetuity," Warner said.

The mileage tax was being studied as an alternative to the fuel tax, looking toward the day when vehicles would run on something other than gasoline or diesel.

Warner said there's been a lot of corresponding work done on the federal level, with Congressmen Earl Blumenauer of Oregon and James Oberstar of Minnesota, chairman of the House Transportation Committee, having expressed interest in the research.

"Our work will continue to inform the conversation, and we'll see where it leads," Warner said.

In 2006 and '07, the task force tested a mileage tax based on GPS technology in the Portland area. Participants were charged a mileage fee equivalent to what they would have paid in gas tax.

Meanwhile, the transportation package signed by the governor Wednesday calls for, among many other things, a study of congestion pricing in the Portland metropolitan area. That's the idea that people would be charged a fee for driving during times when traffic is heavy.

HB 2001, the transportation package signed Wednesday, calls for pilot programs, at least one of which would have to be carried out within three years.

"Pilot programs may include, but need not be limited to, time-of-day pricing with variable tolls," says the new law.