Oregon charged all the volunteers the same 1.2 cents for each mile driven, although the rate could be adjusted as necessary. The technology could be used to charge motorists more for driving during rush hour or less for off-hours. Certain zones could also be deemed congestion areas and higher fees could be assessed.
So, states could actually tax people more for driving through city centers during their morning commute than a farmer on a rural road at midnight. States could also charge higher rates to SUVs and lower rates to hybrids if they wanted to encourage the use of more fuel-efficient vehicles. Such tracking has drawn concerns from privacy advocates, although VMT supporters say such issues can be resolved.
In Massachusetts, Gov. Deval Patrick, a Democrat, recently proposed a voluntary pilot program for his state, similar to Oregon's. The legislation is still pending. In Colorado, there is also a bill that would create a similar VMT pilot program.
In some states, residents and businesses have vehemently objected to such proposals.
A survey of Idaho small-business owners by the National Federation of Independent Business' local chapter found that 80 percent of its members opposed to a VMT plan floated by Gov. C.L. "Butch" Otter, a Republican.
And, in Rhode Island, Republican Gov. Donald L. Carcieri quickly distanced himself from a "Blue Ribbon" transportation funding panel he created after it suggested a miles-driven tax as one of several options.
"There are no plans to move forward with that at all," Cariceri spokeswoman Amy Kempe told ABC News. "He's not considering it at this time.
"They had to look at all funding streams and all funding opportunities. They did a little outside-the-box thinking and that's all well and good … but the governor has already said that's one he doesn't want to move forward with."
ABC News' Lisa Stark contributed to this story.