confusing me with red, yellow and green traffic lights
San Jose uses those yellow orange low pressure sodium lights because of Lick Observatory on Mt. Hamilton. Traditional streetlights emit light over a broad range of the visual spectrum, with white lights emitting light over most of the spectrum. These low pressure sodium lights emit light in a very narrow part of the spectrum. The observatory's telescope can filter out this narrow part of the spectrum, enabling it to see the sky as if there wasn't much light pollution.
it's to detour light pollution because there are 3 observatories in San Jose UCSC on Mount. Hamilton, Evergreen College, and James Lick Observatory also on Mount Hamilton.
If you can't tell the difference between street lights and traffic lights perhaps you shouldn't be driving. The yellow street lights are for reduced sky glare. The yellow traffic light means prepare to stop.
Very close to San Jose is Mt. Hamilton, one of the highest peaks in the Bay Area. At Mt. Hamilton is Lick Observatory, which has a very large telescope for astronomers to study the night sky. Unfortunately, the population density of the San Jose area is very high, which means it produces a lot of light that obscures the vision of the telescope. Yellow lights do not interfere as much as traditional white streetlights, so San Jose uses them to try to cut down the light pollution.
GREEN = GO YELLOW= SLOW DOWN RED= STOP =]
