System of traffic lights praised

Traffic-light systems in the metropolitan area are more efficient than in most other regions in the country, the National Transportation Oper- ations Coalition said yesterday. The District scored a “B” and Northern Virginia scored an “A,” compared to the national average of “D,” according to the group’s 2007 National Traffic Signal Report Card.

D.C. Department of Transportation spokesman Eric Linden said the city has worked hard over the past year to upgrade and adjust the timing of its 1,600 traffic lights.

“We made some progress,” he said. “If the speed limit is 25 mph and you are driving that speed, you are more likely to get a green light at the next intersection.”

Mr. Linden also said road crews are constantly adjusting the timing on red lights and are engaged in a “balancing act” between keeping vehicles flowing through the city and giving pedestrians enough time to cross streets.

“It’s not about only cars,” he said. “It’s about pedestrians.”

Virginia received an overall score of “B,” said Britt Drewes, a state Department of Transportation manager.

Maryland also scored a “B” for improving the signal system during the past year. The State Highway Administration is responsible for 220 such systems, which are composed of 2,500 signals on 17,000 miles of roads. The agency spends $19 million annually to install, refine, monitor and refine traffic signals.

Agency spokeswoman Valerie Edgar said the state also has worked closely with the District’s transportation department since the September 11 attacks to improve traffic flow into and around the nation’s capital.

She also said one of the biggest improvements in Maryland has been the installation of 200 audible pedestrian signals throughout the state to help the hearing-impaired, especially at busy intersections.

Similar signals that also help visually impaired pedestrians have been installed in Silver Spring, said Tom Pogue, a spokesman for Montgomery County’s Department of Public Works and Transportation.

Mr. Pogue said the biggest problem in the county is the volume of traffic and that traffic signals and adjustments to them can only do so much.

He also said the county’s red-light camera system might improve the situation. Montgomery now has 10 cameras being rotated among 15 locations.

The report card was compiled from information from 417 agencies in 47 states, which oversee about 45 percent of the traffic signals in the country. The analysis came from reports based on signal operation, signal timing, maintenance, traffic monitoring and management.

“Our research shows that just a few small changes in the local management and operations of traffic signals could result in national fuel savings of up to 10 percent, or 17 billion gallons per year,” said Marshall Elizer, a spokesman for the coalition.

He said such changes also would result in a reduction of up to 22 percent in harmful emissions.

Among the most improved was Austin, Texas. The city of 709,893 improved maintenance and operations of its 850 signals and raised its grade from “C” to “A” in two years.

“Spending no new money, the city of Austin was able to save more than $40 million in operating costs in just one year by simply changing the way it manages its traffic signal operation,” said Rep. Lloyd Doggett, Texas Democrat.