A gray Mazda pulled over for speeding on the northbound Santa Ana Freeway at Whittier Boulevard: just a ticket, but one of the state's major north-south arteries has crawled to a standstill.
A fender bender between a car and a truck on the Hollywood-Santa Monica freeway interchange: nothing more than a scratch, but traffic has slowed to 10 mph in both directions.
A cat, trying to cross the freeway, is trapped at the center divider of the southbound Harbor Freeway at 51st Avenue. The feline in search of a safe haven has caused humans delays in both directions.
The key to making a minor roadway incident into a major traffic jam? Call it the "looky-loo" syndrome: motorists who cannot resist the urge to stare--at a strange event on the freeway, an accident or even a fellow commuter caught in the snare of the California Highway Patrol.
They turn, watch the commotion, silently thank the stars that they weren't involved--and, at the same time, ease their feet off the collective gas pedal to take a longer look.
Slowdown, and more congested traffic, result.
Looky-loos are a major culprit in clogged freeways, according to James E. Moore, a USC professor of civil engineering and public policy and associate director for the National Center for Metropolitan Transportation Research.
"We have about as big a problem with incidents as with accidents because of the gawking effect," says Moore, who studies Southern California's traffic patterns. "Any time there is an accident within the line of sight of drivers, there's a loss of freeway capacity."
Statistics from the California Department of Transportation indicate that rubbernecking alone can contribute to freeway capacity reductions of up to 26%, whenever an accident or CHP stop is visible to passing motorists.
Looky-loos are enough of a problem that researchers at USC's Center for Transportation Technology have developed a mathematical equation to predict the extent of the traffic shock wave generated by slowing motorists.
The challenge, for law enforcement and motorists alike, is how to prevent traffic incidents from causing major traffic snares.
"Fifty percent of traffic congestion is related to incidents on the freeways like accidents and other things that block lanes or bother drivers," says Steve Finnegan of the Automobile Club of Southern California. "To the extent that we can move those things out of view, that will be an improvement to congestion."
