For Device Driver Download and Updates Click Here >>

Playing God in LA traffic

By: Tom Vanderbilt

Date: Friday, 14. November 2008

This is an excerpt from Tom Vanderbilt's best-selling book TRAFFIC: Why we drive the way we do (and what it says about us).

"Sorry, the traffic was horrible." These five words rival "How are you?" as the most popular way to begin a conversation in Los Angeles. At times it seems like half the city is waiting for the other half to arrive.

But there is one night when being late simply will not do, when the world, -- or at least several million inhabitants of it -- wants everyone to get to the same place at the same time. That would be Oscar night, when 800 or so limousines, ferrying the stars, arrive in a procession at the corner of Hollywood and Highland, depositing their celebrity carriage at the Kodak Theater.

On the red carpet the media volleys questions: "How are you feeling?" "Who are you wearing?" But on Oscar night, no one ever asks a larger question: How did 800 cars get to the same party in a punctual fashion in Los Angeles.

The answer is found in the labyrinthine basement of City Hall in downtown L.A. There, in a dark climate-controlled room with a wall-sized bank of glowing monitors, each showing strategic shots of intersections across the city, sits the brains of the Los Angeles Department of Transportation's Automated Traffic Surveillance and Control (ATSAC).

Traffic centers like this one are essential in many modern cities, and one sees similar setups from Toronto to London (in Mexico City the engineers delightedly showed me footage of speeding drivers giving the finger to automatic speed-limit cameras).

Traffic control bunker

The ATSAC room in Los Angeles would normally be empty on a Sunday, with only the quietly humming computers running the city's traffic lights - ATSAC will even call a human repair person if a signal breaks down. But since it's Oscar night, an engineer named Kartik Patel has been in the "bunker" since 9 a.m., working on the DOT's special Oscar package. Another man lurks at a desk and does not say much. Teams of engineers have been deployed in the field at strategic intersections. On a desk sits a little statue of Dilbert at a computer, to which someone has attached a label: "ATSAC Operator."

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.).

Book cover 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.

"It's calculating demand," says Patel. But it needs to think ahead and say, 'how much time do I need for the next signal?' "

Over time, ATSAC amasses a profile of how a certain intersection behaves during a given time on a given day. Patel points to a computer screen, which seems to be running a crude version of SimCity, with computer renderings of traffic lights and streets but no people.

An alert is flashing at one intersection. This loop at three-thirty on a Sunday has a certain historical value, for a year's period of time, Patel explains. "Today it's abnormal, because it's usually not that heavy. So it'll flag that as out the norm and post it up there as a possible incident." It will still try to resolve the problem, says Patel, within the "confines of the cycling."

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 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."

At times, Patel will have his cell phone in one hand, the walkie-talkie in another , and then the landline phone will ring. "The limos are starting to back up, almost at Santa Monica," someone cries through the Static.

Manipulating the flow

As Patel furiously taps on his keyboard, lengthening cycles times here, canceling a left turn phase there, until it becomes hard to resist the idea that being a traffic engineer is a little like playing god. One man pushing one button affects not just one group of people but literally the whole city, as the impact ripples through the system. It is chaos theory, L.A. style. A long red light in Santa Monica triggers a backup in Watts.

This is when it begins to look as if something odd is going on here this afternoon. Patel seems particularly concerned with the intersections of La Brea Avenue and Sunset Boulevard. "Yeah, Petey, what's up?" he shouts into his phone. "How many people are there? That's good."

Patel then admits that his unit has a "labor problem." Some three hundred municipal engineers, on a sick-out, are picketing in the same streets on which the limos are trying to get to the Oscars. What better way to draw attention, and who better to know the streets on which to demonstrate?

Some of the calls Patel receives are from engineers wondering why the limos have been held up, and some of the calls are from picketing engineers seeking updates about which intersections they should cross on foot.

"Tell them to walk more slowly, they're going too damn fast," Patel says into his phone. Reports coming in say the police are hustling the picketers across the intersections, so as not to block traffic.

"Oh my god, how can they kick you out? You have a legal right to cross. Any unmarked crosswalk you can cross it - just keep on crossing there, moving slowly."

Patel is both trying to get the limos to their destination and coaching the picketers how to best interrupt that progress. Does that mean he can give the sign-toting pedestrians more time, which would further their cause? A strange smile crosses Patel's face, but he says nothing.

He later excuses himself and goes to an office in the back where he takes phone calls. Is he a co-conspirator? Or does his traffic engineer side override his labor solidarity side? One cannot say for sure, but interestingly enough, Patel and another engineer were later charged with tampering with traffic lights at four key intersections as part of the ongoing labor dispute, and the case, which attracted the attention of the department of Homeland Security, was in criminal court at the time of this writing, with the defendants facing several years in prison if convicted.

Despite the picketers, the limos arrive on time. The winning picture, ironically, is Crash, a film about Los Angeles Traffic on literal and metaphorical levels.

Then the limos leave the Kodak theater, rejoining the city's traffic, and head for the post-event parties.

* Tom Vanderbilt writes on design, technology, science, and culture, among other subjects, for many publications, including Wired, Slate, The London Review of Books, Gourmet, The Wall Street Journal, Men's Vogue, Artforum, The Wilson Quarterly, Travel and Leisure, Rolling Stone, The New York Times Magazine, Cabinet, Metropolis, and Popular Science. He is contributing editor to the design magazines I.D. and Print, and contributing writer of the popular blog Design Observer.

TRAFFIC can purchased be from

Further comments to this article have been disabled.

All Comments (1)

Showing 1 - 1 comments


I knew the trafic guys had contorl over lights but not this much. and the bit about those circles on the pavement, I didn't knwo about those. I think if drivesr knew more about traffic lights they would drive differenlty

Truck Driving Jobs

driving information
other driver info
travel information for drivers

Travel and Driving