The state of Oregon is currently running a small test program with five different ways of paying a vehicle-miles driven tax:

The new usage charge pilot program, which began in November and runs through the end of this month, involves about 40 volunteers from state government. Participants chose the tracking plan that best fit their privacy tastes and will pay 1.56 cents for each mile driven — receiving a credit for any gas tax paid during the test period. The idea is to make sure each tracking option works in practice…

The five tracking plans vary in terms of oversight. Two are managed by the Oregon D.O.T., three by a third-party vendor. They also vary in terms of payment: some require setting up an online account tied to credit or debit information, others go the old fashion route of monthly bills payable by check.

The key difference is the tracking system. Two advanced plans track mileage data as well as movement with a G.P.S.; the advantage here is that users aren’t charged a fee for driving on private or out-of-state roads — only public roads in Oregon. Two basic plans involve an odometer-type device that collects mileage data but has no G.P.S. to track movement. Users may end up paying a little more, but they’re getting privacy in return.

The most primitive plan, for people who want the most privacy, uses no tracking device at all. Users pre-pay a flat fee that assumes a monthly mileage. At some point, say when the car gets official inspections, the odometer is checked and the difference between miles paid and miles driven is reconciled…

Despite these cautions, Oregon is preparing to take its system public soon. The state legislature has prepared a bill that would implement a V.M.T. fee on all vehicles getting 55 miles per gallon or better. (The change only applies to car models beginning in 2015, however, and as currently written the law wouldn’t go into effect until that year.) Olson says the bill will be introduced sometime in 2013.

It sounds like this small test is more about finding about which of the five options are doable and/or appealing, mainly on the dimension of privacy, rather than asking whether a vehicles miles tax should be implemented at all. As the article notes, a bill will come up this year to start the ball rolling. If this is the case, why not run a test bigger than 40 state employees?

Another thought: the system is set up so that drivers only pay for driving on Oregon’s public roads. Wouldn’t a comprehensive system of driving tax collection have to account for driving in other states?