Image: Sfbaybridge at night

Description: Western Span of the San Francisco-Oakland Bay Bridge at night. The illuminations on the cables, while part of the original design, are actually a relatively recent addition, made practical by the availability of high efficiency compact fluorescent lamps. The original roadway illumination was by low pressure sodium vapor lamps, which while efficient give off a garish monochromatic yellow light. On the lower deck these have been replaced with tubular fluorescent lights attached to the bottom of the upper deck, while on the upper deck the illumination is by high pressure vapor lamps, which give off a more full spectrum light.
Title: Sfbaybridge at night
Credit: This photo is from a newsletter prepared by the Federal Highway Administration of the US Department of Transportation. http://www.environment.fhwa.dot.gov/strmlng/newsletters/may05nl.asp http://www.environment.fhwa.dot.gov/strmlng/newsletters/images/may05nl_1.jpg
Author: uploaded by Wolfgang K
Permission: This image is a work of a United States Department of Transportation employee, taken or made as part of that person's official duties. As a work of the U.S. federal government, the image is in the public domain.
Usage Terms: Public domain
License: Public domain
Attribution Required?: No