San Francisco, California, USA

Stretching 1.8 miles across San Francisco Bay, the San Francisco Oakland Bay Bridge is a valuable commercial and transit link between the metropolitan hubs of San Francisco and Oakland, California. The double-decker suspension bridge was the longest bridge in the world at the time of its construction, and today transports more than 100 million vehicles per year.In honor of the bridge's 75th anniversary in 2011, Illuminate the Arts and the California Department of Transportation joined forces with renowned light artist Leo Villareal to transform the bridge's western span into a breathtaking, monumental light sculpture. Over the six-month installation, 25,000 Philips Color Kinetics eW Flex SLX nodes were mounted on vertical suspender cables connecting the bridge's deck and its main cables. The 4000 K white-light LED nodes were spaced 12 in (610 mm) apart, creating a low-resolution electronic canvas designed to feature Villareal's unique programming.Using a custom control solution, Villareal programmed each node to create complex algorithms and patterns along the bridge's western span that can recombine into a theoretically endless set of displays over the life of the installation. The lighting faces north and is viewable from San Francisco, but not by drivers on the bridge.The installation is predicted to be seen by more than 50 million people and generate nearly US $100 million in revenue for the local economy over its planned two-year lifespan. As an additional benefit, due to the energy-efficiency of the LED products used in the display, the installation will incur an electrical cost of only $30 per night.