The Seattle Times has an overview of the long-awaited results of the federally funded, multi-million "Traffic Choices" study conducted by the Puget Sound Region Council (PSRC) to look at the viability of widespread road tolling throughout Greater Seattle. The PSRC describes the research as "the most comprehensive study of demand response to network tolling in existence." A summary of the study can be found here (pdf).

The study looked at tolling the entire network of major highways and roads in the region and tested the idea of variable pricing where toll rates vary depending upon the time of day. Participants in the study had their travel tracked by a GPS system in their vehicles. When their basic travel patterns were established, they were given money in an account to "pay" for the theoretical tolls. If they spent less than was in their account — presumably by smartly changing their driving patterns — they could keep the difference. That gave study participants a risk-free financial incentive that would approximate real-world conditions without causing them any pain. In the real world, however, there would be pain, the study acknowledges, but also gain.

The study is upbeat on the benefits of road tolling — it found the case for it "compelling" — though it doesn't underestimate the difficulties in implementing it, which are less technical — they found that tracking road use is expensive, but feasible — but more a matter of policy, politics, privacy, and fairness. However, they conclude that pricing will work to reduce congestion:

The Traffic Choices Study has demonstrated that households and motorists faced with variable tolls do make the small adjustments in their travel that will translate into large-scale reductions in roadway congestion. Many study participants even characterized their travel changes as minor, but the sum total of all their individual decisions can be shown to result in important shifts in the time, amount, and mode of travel so as to minimize the amount of time the region's residents would be stuck in traffic.

However, the public is skeptical about road rationing and the "Traffic Choices" study. As other papers on congestion pricing have reported, to make it generally palatable, the benefits will have to be more than incremental improvements in commute times, especially for drivers who have little flexibility or will see minimal changes in road conditions. For example, what are the benefits for a driver who commutes on an un-tolled road and sees congestion there increase as a result of tolling elsewhere? To offset that, some portion of the massive revenues raised through tolling could be funneled back to create benefits for everyone. That could be in the form of cutting existing transportation taxes, like the gas tax — and heavy investment in public transit (more buses) or in making improvements in problematic traffic corridors.

Because widespread tolling requires a kind of Big Brother level of technology — tracking systems and video surveillance for enforcement — privacy concerns were also shown to be high. In fact, study participants with the most concern going in about privacy were generally even more concerned afterwards. Same with participants with the least concerns going in. Those in the middle seemed somewhat assuaged.

Aubrey Davis, former chair of the state Transportation Commission and chair of the PSRC's Road Pricing Task Force, a group tasked with researching and recommending regional road pricing strategies, tells the Times that he thinks such a pricing scheme is definitely in our future:

"We're going to have to lose a couple elections (on new transportation-tax proposals) before people will take this seriously," Davis says. "I have no doubt we're going to go down this road. I just don't know how far, or how fast."