The central Puget Sound region of Washington State used to be famous for its spectacular mountain-to-bay scenery, painted in a hundred shades of green and blue. Now it is famous for its traffic. Everyday, trucks and cars slowly snake bumper-to-bumper for miles through this lovely landscape on I-5, I-405 and other freeways and arterials.

It is not a commuter's paradise, and it is predicted to get worse, 60% worse, within the next 30 years. That is why the Puget Sound Regional Council, in partnership with the Washington State Department of Transportation, launched a study to test the effects on traffic congestion of turning many roads in the area into virtual toll roads via the use of a satellite-based toll system.

Funded by the Federal Highway Administration, the year-long “Traffic Choices Study,” involves fitting 500 vehicles from over 300 volunteer households with onboard GPS devices supplied by Siemens. The GPS technology enables the computerized toll system to immediately identify a vehicle's location. That location information plus time of day are used to apply a per-mile highway usage toll, which is displayed for the driver as he or she approaches the fee-for-use highway or highway segment. The tolls are automatically deducted from ‘endowment accounts,’ established for each participant.

Charges vary from 50c/mile on certain freeways during peak evening commute hours to 5c/miles on non-freeways during lower use periods. There is no fee for driving between 10:00 pm and 6:00 am, which might be a bit of good news for truckers who like to run at night if the test system were ever to be put into actual use.

The study is scheduled for completion in December 2005; a final report is due in 2006. The hope is that it will shed some light on how much congestion relief such a toll system might provide and how much revenue it might generate for the state.