The Leonard P. Zakim Bunker Hill Bridge in Boston, Massachusetts, USA is one of the widest cable-stayed bridges in the world. Named for both the local civil rights activist Leonard P. Zakim and the American colonists who fought at the Battle of Bunker Hill, the ten-lane bridge spans the Charles River and carries more than 200,000 cars each day to and from major interstates on the north side of the city. At night, lit with bright blue light, the Zakim Bridge is an instantly recognizable feature of the city skyline. In an interview with The Boston Globe, bridge architect Miguel Rosales said “The bridge is supposed to have the feel of a regal entry to Boston, the towers bathed in blue, the cables highlighted in gleaming white."
By 2012, the metal halide lights on the bridge, in operation since the bridge first opened in 2002, had started to deteriorate and had become noticeably dim. Concerned citizens saw that this emblem of their forward-looking city had faded, and they began to express their concerns to the Massachusetts Department of Transportation (MassDOT).
Signify worked with MassDOT to relight the bridge towers with a state-of-the-art connected LED lighting system and helped them understand how the lighting industry's most advanced and innovative technology could reduce energy and maintenance costs. They also explained how MassDOT could also use digital LED lighting controls to change the colors of the lights with the touch of a button, for example, to commemorate holidays and special occasions, and in the future, to potentially indicate traffic conditions.
In turn, MassDOT shared the challenges they face to keep roadways, bridges, and tunnels safe and operating day and night. Relighting the Zakim Bridge seemed especially problematic: it would be costly to rewire for a new lighting system, and would possibly require excavation, lane closures, and disruption to traffic.
Signify introduced MassDOT to IntelliPower, a solution from the Philips Color Kinetics business that leverages existing electrical and physical infrastructures to enable the affordable installation of dynamic, digitally controllable LED lighting systems. By using IntelliPower, MassDOT was able to use the existing wiring and fixture mounting points on the Zakim Bridge, which dramatically reduced the cost of relighting the bridge. MassDOT replaced the old metal halide fixtures with Philips Color Kinetics ColorReach Powercore LED floodlights.
The new LED lighting system, which reduced energy consumption by more than 80%, was unveiled in December 2012. Now the city's signature image shines brightly once again.