DISPATCH FROM A TRAFFIC SYMPHONY

In L.A., Engineers Carefully Orchestrate the Flow

Christabelle Alacar is one of 15 engineers who operate the nation's most sophisticated traffic-management system.
Christabelle Alacar is one of 15 engineers who operate the nation's most sophisticated traffic-management system. (By Sonya Geis -- The Washington Post)
By Sonya Geis
Washington Post Staff Writer
Thursday, May 25, 2006

LOS ANGELES -- To hear Kartik Patel talk, one would never guess Los Angeles is famous for traffic jams. Patel, a civil engineer, has spent the past 11 of his 32 years managing traffic here. He takes pride in the flow.

"You really know when you cross from the city of Los Angeles to other cities," he says one morning from a seat in front of a bank of computer screens. "When you cross that line into Beverly Hills, you know."

Patel is right. Traffic really is slower in Beverly Hills.

That's because Beverly Hills doesn't have an Automated Traffic Surveillance and Control system, and neither do Long Beach, Pasadena or any city besides Los Angeles. Commuters in Chicago, New York and the District can only dream of the sophisticated system that can be found four levels below Los Angeles City Hall.

Traffic here is the most carefully orchestrated in the country. The central computer system, known affectionately by its operators as ATSAC, reads information from thousands of motion detectors and cameras hidden along city streets and then times the stoplights accordingly. Engineers fiddle with the controls to speed limousines down Sunset Boulevard, for the Academy Awards, or to ease traffic around Dodger Stadium. About 15 years ago, a City Council member grumbled about paying for the system, so engineers shut it down. Gridlock developed immediately.

"No one times [the lights] better than we do, and no one moves as efficiently as we do," Patel says proudly. "All this is happening, and most people don't even know it's happening. That's the beauty of it."

The system has grown exponentially since it began as a demonstration project connecting 118 Los Angeles stoplights during the 1984 Olympics. Now ATSAC controls 3,200 of the 4,200 signaled intersections in the city. City officials plan to connect them all within three years.

Video cameras mounted on buildings or perched on 45-foot poles beam images back to the ATSAC headquarters. Dark loops embedded in city streets read the speed of cars traveling over them and feed information to the central computer. When speeds are low, the computer automatically lengthens the green-light time and shortens the red.

Street sensors also read information off transponders -- black disks resembling hockey pucks -- attached to city buses and ambulances. The computer tracks bus spacing and will change the lights to speed them along.

Engineers can also program stoplights to maximize the number of green lights for drivers traveling at certain speeds. Patel brings up a graph showing the number of greens a driver traveling 40 mph will hit on one main drag in northern Los Angeles.

But wait a minute -- 40 mph? Isn't the speed limit there 35?

"Yeah, well, some are set at the speed limit," Patel says a bit sheepishly. "I try to set them five miles above because that's what people drive."

Other cities have pieces of the system, but none combines all the capabilities of ATSAC.

As Patel explains the system, video images of intersections flash on seven flat screens overhead. On a recent Saturday morning, 70,000 people are arriving for a 5K run for breast cancer research in central Los Angeles. We watch the cars line up on one street and get directed by police away from another. This requires hands-on management, both on the street and back at City Hall.

Behind Patel, Christabelle Alacar, 26, sits facing an inner ring of computers with her hand on a mouse. Her hair is in a ponytail, her beat-up backpack lies next to her, her feet are shoved in a pair of old sneakers. She looks about 15. Are all the traffic engineers guiding drivers through the city this young?

Alacar laughs. "If you learn it right out of school, you can pick it up faster," she says.

Patel says: "We're mostly under 45."

Alacar listens on a walkie-talkie to the chatter of city employees who can be seen on the video screens moving cones. About every 10 minutes they radio to her.

"Let's try favoring Normandie at Jefferson and also at Expo," one says.

"Roger," Alacar responds. Click, click, click. Now the light at Normandie Avenue and Jefferson Boulevard stays green longer for cars traveling north-south than for cars going east-west.

Engineers are posted for special events, such as the breast cancer run and recent pro-immigrant demonstrations. Someone also monitors the system from 6 a.m. to 7 p.m. daily. If the computer detects abnormalities, it automatically pages an on-call staff member.

It looks like magic. But with all of this sophisticated technology, why does Los Angeles still have the worst traffic congestion of any city in the nation?

John Fisher, assistant general manager of the Los Angeles Transportation Department, blames constant growth and highways ill-equipped to handle the daily glut of vehicles. "Normally you would want a freeway system to handle through traffic," he says. "But it's spilling over to the arterial streets because the freeways are so saturated."

Or, to put it more bluntly: "You can't shove an infinite amount of water in a pipe," Patel says. "When I give people tours and they see what we do, they understand -- it's just too many cars."


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