When it comes to Boston’s notoriously tangled matrix of streets, which are a challenge for local drivers and a nightmare for visitors brave enough to try navigating them, a seventh-floor command center in City Hall is where a team of engineers does its best to make order out of chaos.
The center utilizes a complex system of video cameras that can zoom, tilt, and pan in on the city’s busiest intersections, allowing staff to play Big Brother monitoring cars and pedestrians on the roads. Sixty-four percent of Boston’s traffic signals are under the city’s direct control, meaning that staff have the power to manually change signal times to make traffic flow more smoothly in the wake of accidents, construction, bad weather, or excessive congestion.
“This is our war room,” says Thomas Tinlin, the commissioner of Boston’s Transportation Department, ushering visitors into a seventh-floor command center at City Hall filled with dozens of video screens monitoring traffic across the city. “Twice a day, we go to war.”
Cities across the nation are making synchronization a high priority as part of a broader effort to reduce traffic congestion and the vehicle idling that contributes to pollution and global warming. Some of the efforts are fairly straightforward: promoting alternate forms of transportation, such as mass transit and bicycling; redirecting traffic to less congested roads; and trying to convince pedestrians and drivers to coexist peacefully. But many municipalities are also working on high-tech solutions to congestion, using road sensors, cameras, computers, and even specially designed apps to keep traffic moving as fast as possible.
Boston faces a particularly daunting challenge in keeping congestion at bay. Between 600,000 and 700,000 vehicles pass through or drive into the city each weekday, bringing in people that more than double Boston’s population. The city was recently ranked No. 10 in the country for worst traffic by INRIX, a traffic information and services group, behind cities such as Los Angeles, San Francisco, and New York.
Managing Boston’s traffic is particularly difficult because it is a city with roadways that tend to meander rather than follow the type of rectangular street grids common in New York or Chicago. Boston’s intersections are also challenging. John DeBenedictis, the engineering director for Boston’s Transportation Department, used to work for Florida’s transportation department. He says a typical Florida road might have one traffic light over a quarter-mile stretch, whereas Boston often has three lights. “It’s just more difficult to coordinate signals more closely spaced together,” he says.
Boston’s drivers are notorious for being aggressive behind the wheel, but Tinlin says the city’s pedestrians are also aggressive and often move about the city in ways that contribute to traffic congestion. “You see some crazy stuff,” Tinlin says, referring to pedestrians he has seen on the city’s traffic cameras who step onto busy roadways, eyes glued to their smart phones, causing traffic to snarl.
DeBenedictis says safety is the city’s top priority, which explains why it’s not uncommon for city officials to have all lights at an intersection turn red simultaneously so pedestrians can cross safely. He says turning all lights red at once slows traffic down but is necessary to avoid pedestrian accidents.
Boston’s traffic signals became a minor issue in the city’s mayoral race this summer. At a forum at The Palm restaurant in July, the candidates were asked about their transportation priorities. City Councilor Mike Ross began ticking off ideas for late-night MBTA service, new taxi regulation, and more emphasis on bicycle and pedestrian traffic. “We also need to have a smart-grid system for traffic,” he said. “Even on the way over here, in 2013, I watched as every light along the surface artery was completely ill-timed.”
Ross later said his experience on the Rose Fitzgerald Kennedy Greenway that morning was not unique, suggesting that the city isn’t using technology effectively to time or synchronize its traffic lights. “I think we can do a lot better,” he says.
But Tinlin says the city is already using traffic technology effectively. He says Ross that morning in July was probably just a casualty of the city’s war on traffic congestion. “There are times when volume can just overburden your network,” Tinlin says. “During rush hour, synchronization can only get you so far.”
Boston’s traffic lights have been timed to some extent since the 1980s, but Tinlin says the agency has taken a more proactive approach to traffic management in the past several years. In 2007, staff members using engineering studies began retiming traffic lights every five years on a rolling basis to account for changing traffic flows. Traffic patterns are constantly evolving as new office buildings and apartments pop up. The Seaport District is a case in point. As new buildings open there and tenants move in, the traffic changes and the timing of the lights needs to be adjusted.
Retiming a light costs about $5,000, and adjustments are typically based on the distance between lights, turning patterns at the intersection, and counts of vehicles, pedestrians, and bicyclists using the intersection.
Nearly 550 of the city’s traffic lights can also be adjusted on a day-to-day basis from the command center in City Hall. Engineers make calls about which lights to adjust by studying video feeds from 506 traffic and intersection cameras and tracking vehicle traffic using a system of magnets placed underneath roads.
Tinlin says he is constantly amazed how an accident or ongoing construction at one location can affect traffic patterns miles away. Construction work on the Longfellow Bridge linking Boston and Cambridge, for example, required an extra 23 cameras to monitor detours and affected traffic patterns as far away as Massachusetts Avenue, Tinlin says. He also says spillover congestion from the Massachusetts Turnpike, Interstate 93, as well as the tunnels and bridges leading into the city can lead to back-ups in the city. Tinlin says his staff must constantly assess the city’s traffic system as a whole, and never focus on one intersection or series of intersections.
The system seems to be working. Internal reports covering the period from 2007 to 2012 indicate the city’s traffic management system has cut traffic delays by 29 percent, auto emissions by 12 percent, fuel consumption by 12 percent, and crashes by 8 percent. By assigning a dollar value to commuter time and the other variables, city officials estimate every dollar they invest in retiming lights yields a $47 return.
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| Boston’s traffic flow is monitored inside a command center on the seventh floor of City Hall, where officials can adjust traffic signal times to ease congestion. |
The 301 traffic lights not controlled remotely by city officials likely won’t be added anytime soon. “I’d love to have all of them linked up,” DeBenedictis says. However, he adds, it’s probably not worth the cost, since the signals are located in more remote neighborhoods where traffic isn’t as problematic. “It just becomes a time and money issue,” DeBenedictis says.
Tinlin says his department isn’t just relying on traffic signal management to speed up traffic. He says his agency tries to reduce cars on the road by making it convenient for people to take mass transit, share cars, and ride their bikes. Technology also plays a role, from message boards set up outside Russia Wharf telling those exiting the parking garage the best route to the Southeast Expressway to apps that warn users about heavy traffic ahead so they can find alternate routes.
Tinlin also says his agency is hiring an outside vendor to develop a smart phone app that will allow users to quickly navigate to an empty parking space. The app relies on sensors being installed at each parking space that will indicate when the space is free, and allow the user to use GPS to find the space. Tinlin says the payoff could be big: 30 percent of non-peak traffic in Boston consists of drivers circling on city streets scouting for parking spaces.
Los Angeles has already taken its traffic management to a whole new level, putting all of its 4,500 lights under central control. A spokeswoman for the Los Angeles Department of Transportation says synchronizing the city’s lights, a project that cost more than $400 million, has brought travel time down 12 percent and travel speed up 16 percent since 1997. DeBenedictis says what Los Angeles is doing is very similar to what Boston already does, except on a much larger scale.
But the new Los Angeles traffic management system, implemented last spring, is different for one other reason: it links vehicle detectors to computers that can automatically update signal timing to manage congestion—without any human assistance. DeBenedictis isn’t quite convinced, saying he values having staff gauge problems and make the changes on their own to avoid automatic changes that could throw the entire system out of synch. “Based on our experience, we believe that it is more efficient to have engineers evaluate the data and make these timing adjustments than having everything automated,” he says.
But there’s no denying that traffic technology is changing rapidly. “What LA is doing is a sign of the future,” says Phil Caruso, deputy executive director for technical programs at the Institute for Traffic Engineers in Washington, DC. He says Los Angeles is experimenting with traffic signals that update on their own but adds that it also won’t be long before the streets are full of vehicles that drive on their own.
“A lot of vehicles have technology that tells if someone is behind you, or if there’s a vehicle on your left, right, or in your blind spot,” Caruso says. “Twenty years from now, you will be able to sit in a car and it’s going to be driving itself.”
Cars that effectively operate on autopilot? That might mean the end of the hot-tempered “Boston driver,” and could therefore be the best traffic management innovation of all.