Cities Design Smart Highways: Next, Smart Drivers
Rather than laying down more blacktop, computers in L.A. help alert drivers to traffic snarls
LOS ANGELES — Four stories beneath Los Angeles City Hall, Sun-Sun Tvedten is directing traffic along the nation's busiest freeway.
From the comfort of a swivel chair, she notices a flashing red light on her computer screen, indicating abnormal congestion in two lanes of the nearby Santa Monica Freeway. Within minutes she activates electronic signs that alert drivers near the area not to access the freeway, but instead to follow "trailblazer" signs through city streets past the site of the congestion before returning to the freeway.
Ms. Tvedten, a transportation engineer for the Los Angeles Department of Transportation (LADOT), is operating the first prototype of what traffic experts call "corridor management of the future." Using an assortment of electronic roadway sensors, TV cameras, ramp meters, and changeable message signs, the "Smart Corridor" may be the model of what traffic engineers across the US adopt in the near future.
"America has run out of its ability to build its way out of freeway problems," says Richard Murphy, lead engineer for the California Department of Transportation (CALTRANS). "We can't just keep widening and putting in more freeways, we have to make better use of what we have now."
Built at a cost of $48 million as a federal demonstration project, the smart corridor here is the largest such project in the country, officials say. Like smaller projects in Phoenix, Atlanta, Chicago, Seattle, San Antonio, and Minneapolis, L.A.'s smart corridor uses sophisticated, new hardware covering a 65-square-mile area encompassing the Santa Monica Freeway, five leading arterial streets and 15 major cross streets. Joint partners include the L.A. County Metropolitan Transportation Authority, LADOT, the Federal Highway Administration, and the police departments of Los Angeles, Culver City, and Beverly Hills.
Heaviest traffic flow
Trafficked by 335,000 vehicles a day, the Santa Monica Freeway is the most traveled in America. Because of costs, environmental and political opposition, as well as sheer lack of space, the future of increased traffic flow is in computerized management such as this.
Experts here say better strategy and coordination can increase rush hour freeway traffic speeds by 6 m.p.h. and reduce the average freeway trip by 12 percent, while increasing the number of cars on the road by 15 percent.
Other states have used sensors, signs, and meters for years, but 00000the Smart-Corridor Project embodies one significant difference: communication links between agencies responsible for freeway traffic and those monitoring city streets.
"This is being widely watched across the country because it is the first to manage the traffic of an entire corridor," says Jeff Brooks, deputy regional manager for the Federal Highway Administration. "Typically, the freeway is run by the state and local streets are controlled by local agencies with very little coordination or communication. This will end that."
When Tvedten logs onto her Smart Corridor computer, she gets the exact same information that her counterparts at Caltrans have thanks to a fiber-optic cable linking the organizations' main computers. The Smart Corridor central computer gathers traffic data from both the freeway and surrounding streets and integrates the information into one cohesive unit.
At the flick of a button, she can learn how much Caltrans officials know about the same incident and what they are doing about it. "There were major incidents in the past where some disastrous crash had occurred on the freeway .... Caltrans raced to the scene, we didn't even know about it," says Tvedten. "Now we are all working out of one database."
Sam Esquenazi, senior transportation engineer for Caltrans, says coordinating tactics is essential because for every minute it takes to clear an accident, traffic remains backed up for four minutes. "A 15 minute accident means a congested queue of cars for one hour," he says, "and a one hour clearance means a half-day of congestion."
Along with such congestion come increased fuel consumption, cost, and waste, as well as significant air pollution. Data released this week show Los Angeles has the nation's most congested streets, wasting 600 million gallons of gas each year in cars that are simply idling.
Besides electronic signs and meters that can help direct traffic, commuters can now tune into a new Highway Advisory Radio and call a Highway Advisory Telephone number. A working map of the corridor is also available on the Internet, with information updated every three minutes so commuters can check congestion before leaving home.
Now just weeks old, the Smart Corridor project is working out some bugs such as phone and radio access. Experts say the system's success or failure may depend on how willing drivers are to take directions given by the freeway signs, and how residents and business owners along the adjacent city streets take to having their roadways choked with cars.
"There is much evidence that commuters are highly unwilling to alternate their routes to work," says C. Kenneth Orski, director of Urban Mobility Corp., a traffic consulting firm in Washington, D.C. "There is also evidence that local homeowners put up fierce resistance to ... shifting cars into their neighborhoods."
David Rizzo, a traffic helicopter broadcaster in Los Angeles, agrees. "I have gazed down in amazement as hundreds of motorists continue on their merry way toward a horrendous accident," he says, "even though several radio traffic reporters and roadside message signs have warned them that the road is blocked ahead."
But for now, officials say the idea is working, at least on a small scale. "My computer tells me how many cars are taking the route I suggest and how many don't," says Tvedten. "Enough of them seem to be doing it that the total amount of congestion we are seeing is diminishing."