@LARGETunnel vision
By Scott KirsnerSeven million dollars, when it comes to the Big Dig's $14 billion-plus budget, is not even a drop in the bucket. It's a li'l bitty molecule of H2O in the middle of the churning Atlantic.
But the seven million is at the core of an interesting technological debate between the Massachusetts Turnpike Authority, which manages the Central Artery/Tunnel Project, and the Boston Fire Department. Should it be spent on a fire sensing system called linear heat detection? Or would the money be wasted, as engineers at the Turnpike Authority argue, because the system is too slow to spot car fires and sound the alarm?
Hardware and software to manage traffic and ensure driver safety are an important part of the Dig. The Turnpike Authority will invest $165 million in an array of advanced technologies, among them loop detectors embedded in the roadway to tell how fast traffic is moving; carbon monoxide sensors to monitor air quality in the tunnels; closed circuit cameras to watch every inch of roadway; and hydrocarbon sensors to detect fuel spills. Seven million of that $165 million figure may or may not get spent on linear heat detection, which uses wires implanted in the ceiling of a tunnel to sense increases in temperature.
The data from all those systems will pour into a room called the Operations Control Center, which looks like something out of the movie "War Games," and is located close to the South Boston entrance to the Ted Williams Tunnel.
I'd initially wanted to investigate the technology behind the Big Dig because I was curious whether it would prevent traffic back-ups in the new ramps and tunnels. Or would the new Central Artery be just as bad as the existing one? In conversations with the Globe's transportation reporter, Tom Palmer, we mused about whether the whole massive project would simply encourage more people to drive into Boston. You know, the same way that whenever Intel designs a faster chip, Microsoft figures out a way to slow it down.
Sergiu Luchian says that won't happen. Luchian is the Intelligent Transportation Systems Manager for the Dig, and he started working on the project in 1982. He says that even with a lot more traffic, he expects to be able to drive his white Mustang convertible through the tunnels' left lanes (the ones away from the on-and-off ramps) at 50 miles per hour most days.
The loop detectors and cameras will look for cars stalled out in the tunnels, and staffers at the Operations Control Center will instantly dispatch a wrecker from one of nine emergency stations situated throughout the project. (The location of each of the stations was optimized with computer modeling assistance from MIT's Intelligent Transportation Systems Lab.) If there are any back-ups -- what Luchian refers to as "quirks" -- OCC staffers can relay detour instructions to drivers over their car radios, since the Turnpike Authority will re-broadcast all of the AM and FM stations in the tunnels.
But the Dig's best design feature isn't the 1,200 loop detectors or its 8000 miles of fiber optic networking. It's the fact that there are fewer entrances and exits in the downtown Boston section than there are on today's elevated Central Artery. That alone should keep traffic flowing smoothly.
Most of the technology at the Operations Control Center, truth be told, is only secondarily concerned with your speed. The primary concern is safety. Clogged roads may get your ire up, but they'll also cause a spike in the level of carbon monoxide in the tunnels, and the Dig's technology has to prevent that, since the Environmental Protection Agency sets strict limits on CO levels.
I was disappointed to learn that technologies to detect hazardous materials aboard vehicles entering Boston's new tunnels aren't yet mature enough -- or cheap enough -- to be part of the project. Luchian talks about the possibilities of having Geiger counters at the tunnel entrances to alert police to trucks bearing radioactive material, or cameras that would be able to read those diamond-shaped "Danger" placards on the side of a truck and automatically sound an alarm.
But, he says, "deployment of that technology would be onerous, and we're always in cost control on this project. There are nine different categories [of hazardous materials] and hundreds of different materials. It would be enormously expensive to try to detect all of them." Besides, truckers entering the tunnel with hazardous materials risk all kinds of fines and punishments, including losing their licenses. Luchian doesn't think it will be an issue.
Which brings us back to the $7 million worth of linear heat detectors. Luchian says that he initially added the heat detectors to the project "out of being prudent, because that was the promising technology." But he says the heat detector technology hasn't improved as much as he'd hoped, and that it isn't able to detect fires quickly enough. As evidence, he cites a pick-up truck that caught fire inside the Ted Williams Tunnel, which had the heat detectors installed when it was built. "The driver got out of the truck and pulled a firebox on the wall of the tunnel," Luchian recalls. "The alarm came [to the Operations Control Center] and to the Boston Fire Department. The linear heat detectors took fourteen-and-a-half minutes to alert us, and by that time, the fire was out."
Indeed, a study of fire detection options conducted by MIT's Intelligent Transportation Lab in 1995 found that linear heat detectors, while they don't generate many false alarms, also take a long time to actually go off. "It's basically the slowest way you could possibly think of to detect a fire," says Alan Chachich, the researcher who conducted the study.
Luchian believes that the new parts of the Central Artery project would be better off without the heat detectors. Fires will get reported to the Control Center more quickly through pull boxes, cameras, loop detectors, and even drivers' cell phones, he says. "Those are better lines of defense." Luchian thinks the Turnpike Authority would be better off saving $7 million now, and installing a more advanced technology later, like a fiber optic version of the heat detector or a camera system that would measure image obscuration caused by smoke or gases.
But some at the Boston Fire Department are skeptical about the Turnpike Authority's motives in removing the heat detectors. "When a decision you make is going to save $7 million, it raises questions in my mind about whether it's the right decision, or whether it's a decision to save $7 million," says deputy fire chief Jay Fleming, who is responsible for fire prevention in the Central Artery project.
"To them, safety is just another thing to cut," says John P. Kenney, another deputy fire chief working on the project. He says he's concerned about lawsuits from people injured or killed in fires that might focus on why the fire department allowed the heat detectors to be eliminated from the project.
Luchian, for his part, describes the linear heat detectors as "more than just the belt-and-suspenders approach. It's a belt, suspenders, and a diaper. [The heat detectors are] not working the way I intended them to work, and I specified them."
Despite the contentious rhetoric, the Turnpike Authority and the Boston Fire Department have arrived at what seems to be an intelligent compromise. The Turnpike Authority will pay to hire an independent fire protection engineer who will review the technology in light of fire codes and existing standards, and make an impartial determination as to whether the linear heat detectors ought to be in all of the Dig's tunnels.
It's almost a foregone conclusion that the engineer will allow the heat detectors to be removed; even deputy fire chief Fleming admits that "he will probably say they don't need it."
If that does happen, Luchian and his colleagues at the Turnpike Authority say they'll continue to seek out the best fire-detection technology for the tunnels. We need to hold them to that, regardless of the project's financial situation.
Scott Kirsner is a Boston freelance writer and a contributing editor at Wired and Fast Company magazines.