California Department of Transportation

Caltrans Has a Brighter Idea: LED Lights on State Bridges

Something about the bridge looks, well, a little different.

Motorists who haven’t passed over the Richmond-San Rafael Bridge in a while may have a pleasant surprise due to the new summer ambience of soft light-emitting diode (LED) illumination on the structure. In place of the once garish orange-yellow pools of light, the LED fixtures now throw off softer, cleaner-looking and more energy-efficient light.

Of course, some drivers may pass by the overhead poles without a thought, vaguely registering that something has changed. But for the more perceptive connoisseurs of antismog and climate change technology, a closer look is warranted. The overhead poles with “cobra lights” have been replaced with softer-illuminating LEDs that resemble, as much as anything, upside-down pancake griddles.

streetlightYou can see the difference between the lights, the old lights give off a yellow-green fuzzy color, while new lights are a warm, white glow. The new type of illumination is the result of a pilot program on the Richmond-San Rafael and Carquinez Bridges, both of which Caltrans owns and operates.

The LED lights are another Caltrans energy-shaving project, saving as much as 60 percent more energy than the old high-pressure sodium "cobra lights." Unlike the cobra lights, the LEDs do not draw extra power when they are switched on. And they last up to 10 years — five times longer than high-pressure sodium bulbs. That not only cuts maintenance costs significantly, but reduces maintenance crews’ exposure to potentially lethal traffic.

A pilot program in 2008 installed the lights
on the Carquinez and Richmond-San Rafael bridges, two vital links in the San Francisco Bay Area. When the new lights passed the initial test without problems, the program was expanded to include the San Mateo-Hayward Bridge and several other locations, including the U.S. Highway 101 on- and off- ramps to the San Francisco International Airport, and the Interstate 280/I-680/US-101 interchange in Santa Clara County.

In the long term, the LED lights could help solve a stubborn dilemma. Public safety requires streets, highways, and parking lots to be adequately illuminated at night. At the same time, the public and private sectors are under increasing pressure to reduce energy use. The LED lights will help ensure continued public safety and will do so with a substantially smaller carbon footprint. Now that Caltrans has field tested the new lights, proving their effectiveness, local governments and businesses are expected to follow.

Caltrans, for example, is experimenting with LED traffic signals, extinguishable LED message signs, and various solar-powered LED systems. At least one maintenance crew in the Los Angeles area has installed LED “smart studs,” raised pavement markers on the Santa Monica Freeway inside the McClure Tunnel near the Pacific Coast Highway to help drivers negotiate the roadway.

These new lights should help everyone see that Caltrans is out in front, leading the way toward a brighter and greener future.