The program will be closely-watched throughout the country because its success or failure will have implications across several policy areas. In Congress, lawmakers have refused to raise the federal, 18.4 cent-per-gallon gas tax for 22 years, and they’ve been unable to come up with a new way to sustain the nearly-bankrupt Highway Trust Fund. A number of other states are considering pay-per-mile policies, and California will start its own pilot program by next year. While a mileage tax has long been floated as an alternative to the gas tax, it’s never been any more politically popular, and according to a Mason-Dixon poll, a majority of Oregonians oppose the state’s plan.

One major concern, unsurprisingly, is privacy. The easiest way to implement and enforce a mileage tax is by outfitting cars with GPS devices, but people are understandably leery of having the government track where and when they drive anywhere. To get around that fear, Oregon is enlisting private vendors to manage the program, which will report only the top-line data to the state. “All the interaction is between you and the vendor,” said Tom Fuller, spokesman for the state transportation department. And participants can opt to use a simple odometer, rather than a GPS tracker, if they want. (The downside is the odometer won’t be able to determine when they drive out of state, so if they don’t want to pay for those miles, they’ll have to submit additional paperwork.) “We wanted to give people options,” Fuller said.

In a way, the privacy workaround is similar to the one adopted by Congress in the reforms to the NSA surveillance programs that passed this week: The government will cede the responsibility of collecting telephone metadata to the phone companies, who can turn it over only in certain circumstances. Because people already entrust so much of their personal information to private companies, the thinking is they’ll be more comfortable with a third party knowing all about their driving habits. And if Oregon’s experiment works, the GPS technology is key to many more wrinkles that could be added in the future, such as forms of congestion pricing. The state, for example, could charge a higher mileage rate in urban areas like Seattle and Portland, or during rush hours.

The Oregon program also heralds a shift in the treatment of fuel-efficient vehicles. For years, state and federal policies were all about creating incentives to encourage people to buy them, as a way of reducing pollution and the nation’s reliance on oil. But as states are increasingly strapped for cash to pay for roads, the pendulum is swinging the other way, and not only in Oregon. A handful of states have now adopted special fees for electric and alternative-fuel vehicles, including three in 2015 alone, according to the National Conference of State Legislatures. “I see the possibility of two laudable policy objectives coming into conflict,” said Deron Lovaas, a senior adviser at the Natural Resources Defense Council.