ATSAC: Behind the scenes at L.A. Traffic Control
I have to admit: the thought of being in a control room documenting technology that moves vehicles more efficiently didn't excite me at first, but once I met Senior Transportation Engineer Bill Shao and the friendly staff at Los Angeles' Automated Traffic Surveillance and Control (or ATSAC), I was full of curiosity.
First off, one of the things that makes ATSAC so unique is that it's one of the only traffic systems in the entire country that is publicly owned. ATSAC was started in 1984 to help move traffic around the Coliseum during the Olympics; since then it has grown to over 3,000 of L.A.'s 4,100 signalized intersections, some of them incredibly complex. The technology is so advanced that even on its busiest days the control room only requires a few people present to run it.
I'm told there are regular group tours of the facility. Next time you visit L.A. I recommend checking it out.
Bill J. Shao: [0:01] This is what LA's traffic used to look like, in circa 1916, at Broadway and Center Street. [0:08] The center was first established for the 1984 Olympics in Los Angeles. The first of its kind in the nation, basically. Trying to handle it with a real time traffic control system.
[0:18] Los Angeles is a very vast metropolitan region. Our agency has 4,400 traffic signals. In New York City, most of the traffic signals are green north, green east. That's about it. In LA, you'll get all sorts of left turn signals. Our intersections are complicated. Big ones, complicated, with bus lanes in the middle. Light rails in the middle.
[0:40] I want to show you our Orange Line, one of the intersections. This camera is near one on Chandler Boulevard, near Laurel Canyon. We're zooming in on one of our locations. The buses traverse right in the dedicated bus way.
[0:53] This is where the bus we just saw, right here. It's bus number, the transponder number. We want to give buses the priority, and if they're ever late on their bus schedule, the system will know that, and we would give priority to the traffic signals downstream such that it allows the buses to reach the next bus stop in a faster time frame.
[1:13] We have 17,000 system detectors buried on a street at this point, and it's expected to grow. It's got 500, or so, vehicles per hour, but the traffic queued... That stop and queue on top of the sensor is only seven percent of the time, meaning that hardly anybody ever stays on top of the sensor, therefore there's no congestion.
[1:31] We currently have about 3,200 traffic signals of our 4,400. It took us almost 30 years to get to where we are. Most other entities throughout the country are relying on proprietary software made by other private companies. This is... We're one of the first public... The only public owned traffic control system that was created in house by the city.
[1:51] We have a research that writes and fine tunes the software and the system side. We know the traffic patterns, and so we create the system custom made to fit LA's needs. So, the system already knows ahead of time what the issues are and addresses them in advance. That's why we call our system Adaptive Traffic Control System.
[2:09] It's green right now, east/west and red for north/south. Every traffic signal that is on our system is second by second. And so, we get the status of the traffic signal. In this case, it's got 702 vehicles per hour, and it's got occupancy, and it's got a certain speed. We collect all this data, and then we compare with the historical trend.
[2:33] And so, it's calling attention on the engineers to pay attention to this particular location. A lot of artificial intelligence is already programmed within the software. And so, this basically comes in as an aid, and to confirm what the system is seeing. The system is so automatic now that we only have one or two on standby as operators. Most other agencies across the country don't really have this capability. Second by second capability is not something that comes about easily.
[3:01] Our information is sent out for free. It's basically public information, and a lot of proprietary traffic tap into that, and then they basically make them available through personal PDAs, and elsewhere.