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Traffic signals disrupted, creating chaos in Montgomery

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The glitch in the traffic lights system in Montgomery County that caused delays earlier this morning is now causing delays in the evening rush hour. Crews are working to repair the glitch and hope to complete the task soon.

"Traffic normally is so congested, and I don't think people realize how much the signals control the flow until something like this happens," said county spokeswoman Esther Bowring.

The system, which she described as "unique" in the Washington region, is based on a Jimmy Carter-era computer that sends signals to traffic lights all over the county. On weekday mornings, it tells them to stay green longer for people headed to work. And in the evenings, it tells them to stay green longer for people headed home.

It also makes them all work together -- green-green-green -- to promote the flow of traffic. That happens automatically, and then the engineers use data from hundreds of traffic cameras and a county airplane to tweak the system. When there is an accident, breakdown or water main break, they use the computer to adjust signal times further and ease the congestion around the problem.

It's great when it works, a disaster when it fails.

The first inkling that something was wrong came shortly after midnight, and as computer technicians were rushing to handle it, the computer crashed completely about 3 a.m. Wednesday.

All of the traffic lights kept working, but they no longer knew what time it was. When they were supposed to switch to morning rush mode, from 7 to 7:30, they kept rocking along at a rhythm better suited to Sunday morning.

By then, county workers had been racing from one major intersection to the next, adjusting each light by hand. But it was too late. Although a flick of a switch could fix one light's timing, only the computer had the power to synchronize a series of traffic lights.

Drivers' frustration was shared by the computer technicians in Rockville, who had isolated the problem by lunchtime but couldn't figure out how to fix it, Bowring said.

"They know where the problem is, but they just don't know what it is," she said. "The server seems to be sending the signal, but the conduit is not transferring the information to the signal lights."

The afternoon commute began badly when an unrelated fatal crash on the inner loop of the Capital Beltway ended with a vehicle in flames on the side of the road.

Bowring said the computer that went belly up Wednesday was being phased out. The county is in the second year of a six-year program that will bring in more modern and reliable equipment.

The malfunction of the Montgomery computers in Rockville happened about the same time as, and a couple dozen miles away from, a power failure at Metro's headquarters that muddled the morning commute for bus and rail riders.

"I called them first thing when I heard about it," Bowring said, "and asked if there could be any possible connection. They said: 'No. There's no conspiracy out there.' "


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