Team lights way to safe crossings

ARLINGTON -- A group of Arlington High School students and their teacher have worked for the past year to devise a system that uses sophisticated electronic technology and bright red lights to make it safer for people to cross the street.

The students, members of Jacques Duranceau's advanced-placement physics class, were scheduled to travel to the Massachusetts Institute of Technology Friday to demonstrate the results of their hard work: a prototype of a cost-effective automatic pedestrian crossing, employing flashing LEDs embedded in a road surface and a pressure-sensitive pad on the adjoining sidewalk to activate the lights.

''It creates visibility for the pedestrian," said Anna Payne-Tobin, a member of the Arlington High Flump Squad (flump meaning ''flashing bump," of course). ''This gives the cars the message that someone is coming into the road."

The Arlington team is one of 10 high school groups in the country selected as 2003-2004 recipients of Lemelson-MIT InvenTeams grants. The organization encourages teams of students, their teachers, and industry mentors to invent something of value for their school or local communities.

The Arlington High Flump Squad includes Michele Kotiuga, Christopher Sacca, Angela Chung, Mary Avila, Andrew Peach, Payne-Tobin, and Duranceau, their adviser and the grant's administrator.

During a recent interview at Arlington High School, Sacca and Kotiuga described how the crosswalk would work. First, Sacca said, a pedestrian who weighs at least 40 pounds activates the system by stepping on a weight-sensitive surface on the sidewalk near the crossing. A coil of piezoelectric material, composed of crystals that become charged when stressed, then signals a switch that triggers the 12 light-emitting diodes to flash. The LEDs -- which emit light from their sides, Kotiuga noted, so they can be easily seen by approaching cars -- are programmed to light in three successive modes: first, flashing directionally, to indicate from which side of the street the pedestrian is approaching; second, continuously lighted, as the pedestrian advances; and third, all flashing simultaneously, to indicate the end of the sequence.

Sacca, who with Peach and Kotiuga designed the circuit that controls the LEDs' lighting sequence, said that the use of piezoelectric materials, frequently employed in intrusion-detection systems, is what differentiates the Flump Squad's invention from existing pedestrian-crossing systems.

''We did a lot of research," he said, ''and found that nowhere else in the country are piezoelectric cables used for this purpose."

Duranceau said the Arlington team's efforts began with soliciting ideas from subscribers of the town's e-mail list on what local problem to tackle. ''One resident wanted us to design a robot to chase away geese from Spy Pond and other places," he said. Other problems residents wanted addressed were controlling water chestnuts and other invasive plant species, Duranceau said, and finding a way in the winter to clear snow from one side of the Minuteman Bikeway while tracking the other side for use by cross-country skiers.

In the end, the group decided to work on the desire of residents to make crosswalks safer in Arlington. ''This fit the town," Duranceau said, noting that the project was enthusiastically supported by Police Chief Frederick Ryan, the town's Transportation Advisory Committee, and the pedestrian advocacy group Walking in Arlington.

In addition to presenting technological challenges, the project turned out to present other kinds of roadblocks. The Flump Squad's first approach to its self-appointed task involved using infrared detection or microwave technology to activate the LEDs, but an Internet search led to the discovery that a California company was a step ahead of the students, and had secured a patent on the method. ''We consulted a patent attorney," Duranceau said, ''and we could have gone ahead, but we didn't want to do something that had been done."

They started over, and came up with the piezoelectric technology approach. ''There was a lot of trial and error," said Payne-Tobin, ''but we learned a lot doing this."

The group's creation is being praised by town and community officials. ''In a densely populated community like Arlington, we're always looking for creative solutions to problems that pedestrians have crossing streets," said Chief Ryan, ''and in this case the outcome will be worthwhile."

Rachael Stark, founder and chairwoman of Walking in Arlington, said she hopes the students' invention, which she likened to ''a tiny landing strip for pedestrians," is eventually implemented. ''I certainly can imagine that this will be a useful thing. The number-one challenge is that people are driving too fast on Mass. Ave. and some other roads. People see a big wide expansive pavement and they just rev up, and they don't see crosswalks clearly enough." The intersection most frequently complained about, she said, is the junction of Massachusetts Avenue and Pleasant Street.

If the Flump Squad's creation is to become a reality in town, it will need the support of members of the Transportation Advisory Committee, which advises the selectmen on transportation issues. Ed Starr, the committee's chairman, said his group would give it serious consideration, perhaps for placement on Massachusetts Avenue in front of the high school. ''If it's rugged enough, and meets the goals that they've set," Starr said, ''I think it should go into an Arlington crosswalk."

Michael Rademacher, a committee member who served as liaison to the group, agreed. He said the design would be particularly useful for people with handicaps: ''This will make it easier for people who can't use their hands to operate a push-button light."

Duranceau said the Arlington students' InvenTeams grant was for $5,600, and he hopes that part of that sum may be used for construction of such a crosswalk system in town. Installing the system would cost less than $1,500 and maintenance costs would be minimal, he said. ''That's the next step: getting this thing in the ground."