http://sports.autoblog.com/2006/03/27/oregon-testing-mileage-based-road-tax-system/
The Beaver State is investigating a new method of assessing taxes used to bankroll state highways. Instead of collecting money via gasoline taxes, Oregon is testing a GPS-based system which levels taxes based upon miles driven.
By switching to such a system, the state would not lose revenue with every resident that purchases a more fuel efficient vehicle.
The 'black box' system keeps tabs on how many miles are racked up both in and out of Oregon's borders, as well as during rush hour, and levies taxes on the totals accrued.
Predictably, the creation of a database that monitors the travel patterns of drivers raises some troubling privacy concerns, even for those who don't regularly harbor 'Big Brother' conspiracy theories.
As things stand, Oregon derives some 80-percent of its highway funding from its 24-cent-per-gallon tax, thus the move towards more fuel-efficient vehicles stands to negatively impact the state's coffers by millions of dollars.