Loss of Power Kills Signals, Snarls Traffic on Valley Streets

A sudden dip in electrical power knocked out about 160 traffic signals Wednesday across the San Fernando Valley, triggering major traffic jams during the evening rush hour, authorities said.

At many intersections, blinking red lights brought traffic to a crawl as cars backed up for blocks. Teams from the city’s Department of Transportation had to manually reset each signal--a drawn-out process that, three hours after the 4:10 p.m. outage, had resurrected fewer than half the affected lights.

About 6,000 Valley residents and businesses also temporarily lost power, said MaryAnne Pierson, spokeswoman for the Los Angeles Department of Water and Power. She blamed an equipment failure at the city’s Sylmar converter station for the problem.

“There was a dip in the voltage and it automatically trips off some systems,� including many traffic lights, Pierson said. “It’s kind of like a surge protector.�

The city restored power to homes and businesses within two hours, Pierson said. But like the traffic lights, electrical systems at some businesses still needed to be reset before they would function normally, prolonging the problem.

Gridlock virtually paralyzed many of the Valley’s main arteries, including parts of Sepulveda Boulevard, Tampa Avenue, Victory Boulevard and Topanga Canyon Boulevard, authorities said.

“I was stuck in maddening traffic,� said Wayne Petty, a Hollywood resident who got caught in the snarl on Sepulveda, near Sherman Way. “It took me about 20 or 30 minutes to get through the intersection. Then I jumped on the freeway and got out of there. It was insane.�

Eddie Curtis, a Department of Transportation engineer, called the delays “a necessary evil.�

Traffic signals are programmed to blink red when something--whether it’s a power outage, a storm or an errant car--disrupts their internal control mechanisms, he said. Once the lights start flashing, each one must be manually checked to ensure that the signal timing is correctly set and that no equipment has been damaged.

“All we can really do is apologize for the inconvenience,� Curtis said. “But this happens really for public safety. If the signals didn’t go into flash [mode], there could be far greater ramifications. Instead of a little delay, there could be accidents.�

No major traffic accidents were reported, police said.

In an unrelated outage, about 120,000 Southern California Edison customers briefly lost power in sections of Culver City, West Hollywood, Beverly Hills, Santa Monica and Inglewood when a crane hit a power line in Inglewood.