When Virginians gripe about traffic jams, they have a point. Traffic in the suburbs abutting Washington usually ranks among the five worst in the nation, according to the Texas Transportation Institute, which tracks urban traffic trends. In the old days, states solved the problem of crowded roads by building new roads, but that didn’t work. “The traditional approach is to add a lane or add a new highway,” says Brian Smith (Engr ’91, ’95), a UVA associate professor of civil engineering and co-director of the Smart Travel Lab, a joint venture between
UVA and the Virginia Department of Transportation. “But when you make the system bigger, you generate new economic development and that generates new traffic. By the time you know it, the new road is congested too. You’re kind of chasing your tail and that’s not a sustainable approach.”
Building new roads is also horrendously expensive, so Smart Travel Lab engineers are trying a more cost-effective tactic: doing more with the system that’s already in place. That would ease the state’s traffic problems, which have grown steadily worse.
“In Northern Virginia, the concept of a peak hour of traffic is long dead,” says Cathy McGhee (Engr ’94), the lab’s other co-director. “We now have a morning peak period that can last from 5:30 a.m. to 9:30 a.m., easily. The same thing happens at night. It’s not far-fetched to say peak periods will eventually meet and we’ll have peak periods all day long.” Moreover, traffic congestion is building elsewhere in the state, including the populous Hampton Roads area.
“It’s not practical to say we can eliminate these problems,” says McGhee. “What we’re trying to do is reduce the intensity and the duration. We’re asking if we can reduce the duration from four hours to two hours. And can we shift it from stop-and-go to traffic moving smoothly at 20 miles an hour? We’re not trying to create the world as we would like it to be. We’re trying to take the world as it is and make it better.”
With information technology, this may be possible, and the methods the Smart Travel Lab has in mind are very high tech. One idea is to use computers to anonymously analyze aggregate data collected from cell phones or GPS navigational systems—two devices that identify a vehicle’s location when they are turned on. Computers would crunch the data using sophisticated algorithms devised by Smart Travel Lab researchers. The vehicle data would be overlaid on traffic grids, with the goal of making subtle changes in traffic signals and highway ramp meters to keep traffic moving.
With such a system, “you could figure out how well traffic is moving, and be able to tell the difference between a crowd of people talking on their cell phones at Starbucks and a highway traffic jam,” says Smith.
But there are variables that are impossible to predict and hard to react to—such as a truck accident that spills a load of live chickens on a suburban Washington highway. No computer could predict how long it would take law enforcement to round up the chickens so traffic could resume. “In any traffic system, there’s constant change and so much complexity,” Smith says. “The incident with the chickens actually happened. Really crazy things happen out there.”
Even so, the Smart Travel Lab is making headway, at least on the research level. “We have done a lot of this work in simulation studies to show it can work,” Smith says.
The current traffic monitoring system is decidedly low tech. Traffic sensors are placed in selected roadways to measure vehicle numbers and their speed. But the system is expensive, hit or miss, and the sensors break down from wear and weather. Authorities also rely on the old standby—the traffic helicopter. In that case, “you’re relying on traffic helicopter information from the last time it flew over an area,” Smith says.
The much broader high-tech approach would keep track of everything, everywhere, in close to real time. This kind of approach makes the job of the traffic engineer a bit different from what it used to be. “When I came out of college, a civil engineering graduate had learned the basic skills of transportation engineering,” says McGhee. “Now we’re looking for people who have both transportation skills and information technology skills.”
In this new world order, says McGhee, traffic engineers “still have to design roadways correctly. But now they also have to wring everything they can out of the system using technology solutions.”