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Explainer: How All Those Oscar Limos Avoid Traffic

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For anyone wondering how in the world those hundreds of limos can arrive on time to the Oscars, here's your answer, courtesy of Tom Vanderbilt's Traffic, published last fall. The Angeles Department of Transportation’s Automated Traffic Surveillance and Control (ATSAC), located in the basement of City Hall, essentially plays god, tweaking stop lights and slowing flashing pedestrian signs. Or at least that's how things when down in 2006, the year that Vanderbilt sat next to engineers on Oscar night (the year "Crash" won best picture). An explainer on the system itself and what might have happened last night: "Since the city cannot shut down the entire street network for the Oscars, the limos must be woven through the grid of Los Angeles in a complex orchestration of supply and demand. Normally, this is done by the system's powerful computers, which use a real-time feedback loop to calculate demand.

The system knows how many cars are waiting at any major intersection, thanks to the metal-detecting "induction loops" buried in the street (these are revealed by the thin black circles of tar in the asphalt.).

If at three-thirty pm, there are suddenly as many cars as there normally would be in the peak period, the computers fire the "peak-period plan." These wide-area plans can change in as little as five minutes. (For a quicker response, they could change with each light cycle, but this might produce overreactions that would mess up the system.)

As ATSAC changes the lights at one intersection, it is also plotting future moves, like a traffic verson of IBM’s chess-playing computer Big Blue....But on this occasion, the engineers want certain traffic flows – those conveying star's limos – to perform better than ATSAC would normally permit, without throwing the whole system into disarray. In the late afternoon, with the ceremony drawing near, it becomes apparent just how difficult this is. Harried requests are beginning to come in from field engineers who are literally standing at intersections."

"ATSAC, can you favor Wilcox at Hollywood?" asks a voice, crackling from [engineer Kartik] Patel's walkie-talkie. Patel, on his cell phone, barks: "Man, did you happen to copy Highland and Sunset? There’s quite a Queue going northbound."

If you read on in this excerpt (linked below) you'll see that questions are raised when Patel seems to help out striking traffic engineers (who are essentially disrupting the Oscars by picketing near the streets). What happened in that case isn't exactly clear, but last month Patel and another engineer pled guilty to illegally accessing traffic lights in August 2006.


Via NBC4: "Prosecutors said the men illegally accessed the city's Automated Traffic Surveillance Center between 9:10 p.m. and 9:30 p.m. on Aug. 21, 2006, and sent computer commands that disconnected four signal control boxes at critical intersections from the system.

Traffic signals were disconnected at four intersections -- Sky and World ways at Los Angeles International Airport; Coldwater Canyon and Riverside Drive in Sherman Oaks; Alvarado Street and Glendale Boulevard at Berkeley Avenue; and First and Alameda streets. No accidents were reported, but it took four days to get the city's traffic control system fully operational, according to prosecutors." We smell a feature movie on this illegal activity, or at the very least, a feature article!

· Playing God in LA traffic [Drivers.com]
· Engineers Plead Guilty to Illegally Shutting Down Traffic Signal [NBC4]