To Slow Speeders, Philadelphia Tries Make-Believe

Matt Rourke/Associated Press
However it may seem, this speed hump in Philadelphia is nothing more than flat pieces of plastic burned into the street. Municipal officials say the month-old program will soon be expanded.

Published: July 12, 2008
The first time Larry Morris spotted the white, blue and orange triangles that seemed to rise up from Blue Grass Road in his Northeast Philadelphia neighborhood, he was unsure just what they were.
“It kind of surprised me,” said Mr. Morris, a retired machine shop welder, “but I slowed down when I went over it, and everyone behind me did too.”
That is exactly what the City of Philadelphia and federal safety officials hope they will do.
The triangles are known variously as 3-D, virtual or just plain fake speed humps. They are among the latest tools in the age-old battle between drivers who exceed speed limits in residential neighborhoods and residents, law enforcement officers and government officials who want to slow them down.
Real speed humps — not to be confused with their more jarring cousins, speed bumps, a mainstay of some parking lots — are rounded mounds of traffic-calming asphalt that generally span a roadway. The virtual variety — flat pieces of plastic that are burned into the street, with the configuration of the colored lines conveying the illusion that a driver is about to cross the real thing — is less expensive ($500 each, versus $2,000), does not impede water flow and poses no threat to ambulances or other speeding emergency vehicles.
Use elsewhere suggests that the effectiveness of a virtual hump can wear off over time, once drivers discover that what they are encountering is not what it seems.
“We call it the novelty factor,” said Martin T. Pietrucha, an associate professor of civil engineering at Pennsylvania State University, who studies human factors in highway safety. “They may get some mileage out of it until people realize, ‘Hey, I don’t get jiggled like with a real speed hump.’ ”
Still, Dr. Pietrucha said, virtual humps can be quite effective as part of an education and enforcement campaign. Even after drivers catch on to them, they can have long-term value as a reminder that slower speeds help prevent accidents and injuries.
The virtual humps, made by a Japanese company, the Sekisui Jushi Corporation, are not uncommon in Europe. But Philadelphia, in a program financed by the National Highway Traffic Safety Administration, is only the third American city to try them, after Phoenix and one of its northwestern suburbs, Peoria.
Philadelphia officials say they are pleased with the short-term results.
“The effect has been quite surprising,” said the city’s streets commissioner, Clarena Tolson. “This was intended to be part of an aggressive and innovative program to slow people down. We have to do something in these neighborhoods.”
Philadelphia first installed the devices in mid-June, when 10 sets of three virtual triangular humps were burned into a half-mile stretch of Blue Grass Road as part of an education and enforcement campaign, Drive CarePhilly.
Before installation, Ms. Tolson said, drivers along that stretch of the two-lane road, often used as a neighborhood shortcut, were clocked averaging 38 miles per hour, 13 m.p.h. above the posted speed limit. A month later, that figure has dropped to 23 m.p.h.
“Now people can get out of their driveways and walk across the street,” Ms. Tolson said.
Like many other municipalities, Philadelphia has tried a variety of devices to slow drivers: real speed humps, traffic circles, curb extensions, rumble strips, slightly raised crosswalks. Other places have tried leaving empty police cruisers near intersections, even erecting life-size cutouts of small children or of a police officer aiming a radar gun.
“It’s an ongoing effort,” said Mike Cynecki, traffic engineering supervisor for the Phoenix Street Transportation Department. “It’s not a one-shot deal. You use whatever will work.”
When Phoenix and Peoria first installed virtual speed humps on 10 neighborhood streets in 2000, officials say, the initial positive results were the same as Philadelphia’s.
“But residents weren’t satisfied,” said Mr. Cynecki, who oversaw the project. “The effect wore off a bit, and some of these residents practically wanted a six-foot wall there. They didn’t think this was enough.”
For now, anyway, Philadelphia’s experience on Blue Grass Road is so good that officials say they will add virtual humps at 130 locations in other residential neighborhoods where speeding has been a problem.
Mr. Morris, the Northeast Philadelphian at first surprised by the devices, is glad to hear it.
“I think anything that slows down traffic and prevents an accident,” he said, “is a good thing.”
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