Reducing the number of cars on the road during peak hours adds to highway capacity, as a roadway can handle more vehicles per hour when bottlenecks and jams are reduced or eliminated. According to Guensler, more vehicles per hour can travel through limited-access lanes because they are less traveled and therefore less congested. "From an engineering standpoint, traffic flow is the product of vehicle speed and traffic density – that is, the speed of the vehicles and how closely are they following each other," he said.

Commute Atlanta collected data from GPS trackers installed in the cars of 470 Atlanta-area volunteer households. At first, average household travel patterns were collected and analyzed. Households who were able to reduce their monthly totals were given financial incentives. In the next phase, commuters will endure simulated peak-hour congestion pricing in which drivers are charged for travel during peak hours. This phase will also test improved tracking devices that eliminate toll booths by automatically detecting and charging drivers who have entered limited access lanes or traveled during peak hours.

If thoughts of tracking devices make you nervous, you may want to participate in the focus groups of The Congestion Pricing Project, separate from Commute Atlanta but also involving Guensler. The project analyzed the opinions of Atlanta-area drivers regarding congestion pricing and limited-access lanes through a series of focus groups. Some of the results were surprising: "Our focus group work revealed interesting points, including the fact that income groups that wouldn’t generally use value priced lanes still liked having them available," Guensler said. "There are times when everyone finds that these lanes are a good economic decision -- such as when you’re late for daycare, and you’re facing dollar-a-minute overtime charges."

Guensler was hard at work when Wired contacted him, but he promised to update us on project progress as implementation continues. We'll keep you posted.