The California Department of Transportation (Caltrans) recently completed an LED lighting overhaul across the East Span of the iconic San Francisco – Oakland Bay Bridge.
Over 1,600 custom-designed fixtures from Musco Lighting, incorporating 51,000 Cree XM-L LEDs have been installed.
"LED technology was chosen for its long lamp life, energy efficiency and optical control abilities," explained Adam DeJong, Musco sales manager. "The performance durability offered by Cree's XM-L LED allowed us to design a solution using custom reflectors to enhance the safety for commuters and highlight the aesthetics of the bridge."
The newly constructed 2,000-foot East Span is designed to withstand earthquakes. In addition to the roadway and suspension cables, it also features custom, optically directed Musco fixtures along the bridge deck, bike and pedestrian paths, tunnel entrance and self-anchored suspension tower.
"Musco was originally contacted on this project in 2008 with a design using metal halide light sources," DeJong explained. "After reviewing the specifications, Musco declined involvement, as the metal halide technology available would not be the best solution for the application. With the long hours of usage on the bridge, a metal halide lamp would have needed to be replaced every two to three years and the exceptional glare control with excellent uniformity would not have been achieved."
They managed to talk Caltrans around. "Musco worked closely with the design team starting in 2008. During that time, Musco built scaled models and did many tests to ensure the system would perform as designed," DeJong added.
The LED solution is expected to use 50 per cent less energy compared to the metal halide design.
