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Los Angeles Completes Long-term Traffic System

A long string of green lights awaits drivers along Ventura Boulevard in Sherman Oaks, California
A long string of green lights awaits drivers along Ventura Boulevard in Sherman Oaks, California, thanks to the LADOT’s ATSAC traffic management system. City of Los Angeles Department of Transportation Staff

Travel times are dropping for commuters now that the last of almost 4,400 traffic signals can be remotely controlled by LADOT engineers, marking the end of a 30-year project.

September 10, 2013—It seems as if every week there’s a new survey naming one city or another as having the worst traffic in the country. Commuters wear the “No. 1” ranking like a badge of honor as they fight through their daily trip to work, listening to traffic updates every 10 minutes in an effort to avoid the worst backups and make it to work on time.

Chief among those battlegrounds has been Los Angeles, where a concerted effort to change the way the traffic is managed dates back to 1984, when the city needed to alleviate the crush of vehicles surrounding the summer Olympic venues. With the completion of an electronic traffic signals system on all of its surface streets, the city can now proudly boast that the time of the average commute in the nation’s second-largest city has improved by about 13 percent. While that might not seem like much, if a 5 mi, twice-daily trip in one of the city’s major corridors was measured over the course of a year, that 13 percent savings would result in a time reduction of more than 22 hours, according to both the city and independent analysts from Texas A&M University.

The hero in this equation is the Los Angeles Department of Transportation’s signal synchronization system, called ATSAC (Automated Traffic Surveillance and Control), which helps engineers manage about 6,500 mi of city streets and almost 4,400 traffic signals. And while Jonathan Hui, a transportation engineering associate with LADOT, says the project may never really be “finished,” the agency was able to say earlier this year that all of its surface streets and signals were able to be remotely controlled by the department from a central location—a significant milestone.

The system’s hallmark is its ability to adapt to congestion without operator input, making automatic changes that will genuinely reduce delays. Some segments of the system are pretimed, based on the analyses of traffic engineers, while others are actuated, which means a signal will not change until a vehicle passes over a detector or a pedestrian pushes a button in order to activate a “walk” signal. Additionally, the city now has a policy in place that prioritizes the movement of trains and buses, encouraging mass transit use.

ATSAC documentation stresses that the system is not limitless: “Once volume reaches a certain point … travel time will increase,” it reads. But a generation of engineers and politicians came together to fight this particular pain point in a city famous for its reliance on the car, and Hui says, “The results of the technology speak for itself.”

Hui adds, “In the City of Los Angeles, traffic and driving and getting around is a huge issue for the people who live here, so it’s always going to be important. Ways of managing that are always going to be [evolving]. The power of our system is we can [now] implement those changes easily and in a comprehensive way.”

The successful decades-long project has been on the radar screen of transportation analysts nationwide. Douglas Noble, P.E., PTOE, a program manager for the National Transportation Operations Coalition, an initiative of the Federal Highway Administration and the Institute of Transportation Engineers that is dedicated to improving the management and operation of the nation’s transportation system, says, “It’s impressive in that they, as an agency, have had this consistency of purpose as part of their overall program for that many years across multiple general managers. It’s pretty unusual as well.”

Neither Hui nor Noble were aware of a similar-sized project being carried out anywhere in the world, but initiatives in Denver, Los Angeles County, the City of Long Beach (California), and Kansas City, Missouri, are similar in nature—and all of them are being monitored by traffic engineers and transportation managers. A 2010 report from the National Cooperative Highway Research Program mentioned 25 adaptive traffic control systems in the United States, some particularly notable for the cooperation they have engendered between neighboring cities, counties, and suburbs. Unlike, for example, the handling of recyclable material or reducing the amount of waste that accumulates in landfills, the goal of easing traffic and reducing commute times is an infrastructure issue that civic leaders and their constituents can get behind—enthusiastically and publicly.

But there still can be some roadblocks along the way. In Los Angeles, the cost of the system came in to question several times over the decades. Hui says the agency reserved the right to shut down ATSAC in a particular corridor to demonstrate the system’s value.

Nevertheless, a full-scale system is costly, and Noble encourages engineers and city or county executives to fully exhaust the capabilities of their current traffic systems before spending millions of dollars on an upgrade that would rival Los Angeles’s. It’s often better, he says, to maintain the signals, controllers, and sensors already in place, and to study traffic patterns, before resorting to a wholesale installation of a new system.

“Many agencies, especially smaller ones, have one or two people who know pretty much everything that’s going on with the system they have and what the current technology is out there. But once you get past those one or two folks, you don’t have the same level of experience,” says Noble. “And these aren’t ‘set it and forget it’-type things. You have to have people who are able to make informed decisions on the capital investment, but also advise senior management or public works directors … on the lifecycle and maintenance costs.”

The three-decade project in Los Angeles—which cost an estimated $410 million paid for by a combination of city, state, and federal fund-raising efforts—may never be precisely duplicated. But it may never need to be. A concerted effort to analyze a community’s real goals for its traffic efforts and then respond accordingly is a concept that is gaining traction, Noble says. For example, some communities may genuinely just need to increase highway throughput, while others may decide to funnel traffic at a manageable speeds into redesigned downtowns and commerce zones, enabling vehicular traffic to coexist with bicycles and pedestrians. (See “Bronx Road Plan Takes the ‘Express’ out of Expressway,” on Civil Engineering online, for example.)

And now that the project has been essentially completed, Noble acknowledges that there are science fiction-like developments on the horizon that could impact the way traffic operates within 5 to 25 years. “Vehicles are becoming progressively smarter,” says Noble—and more “connected,” able to communicate with each other and with the infrastructure. And of course there is also the proposed Google Car and other driverless vehicles that are being designed and tested. “This also provides opportunities and creates complexities relative to traffic management,” he points out. “It’s something to keep an eye on and look forward to over the next five years.”



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