Faced with declining gas tax revenues, the state of Oregon is test-driving an experimental Road User Fee Pilot Program. The program relies on GPS units in cars to record where the vehicles have been, then charges the drivers based on miles driven rather than gas consumed.
Right now, 280 participants are equipped with the GPS readers. They have to purchase gas at two cooperating stations in Portland, where readers subtract the standard gas tax and add a fee of 1.2 cents per mile driven in Oregon.
The Oregon Department of Transportation's Web site assures that "vehicle location data is not collected, [thus] cannot be accessed. The only data collected and transmitted is the mileage, sent to the gas pump reader through a radio frequency that can only travel about three to four feet." But as a requirement of the Federal Highway Administration's Value Pricing Pilot Program—from which Oregon is getting most of the funding for this project—the state is also testing the ability to distinguish miles traveled in congested areas during congested times. For now it only records the fact that tagged cars are in a congestion zone and how long they were there, not specifically when or where.
This method of road financing, if perfected, would allow the government to target prices and encourage us not to drive in congested places at congested times—although one advocate of the program, John Charles of Oregon's Cascade Policy Institute, worries that since the price difference hits you not at the moment of choice, but later at the pump, it won't provide enough incentive to avoid congested zones. The plan would also allow for social engineering —for example, charging a higher per-mile tax for less fuel-efficient vehicles.