Ted Cohn, professor of vision science: "This is light without heat."

Photo by Peg Skorpinski.

Stopping traffic

The red lights you see in kids' tennis shoes will soon be controlling traffic in California, thanks to a test of their visual comparability with traditional stop lights done by School of Optometry scientists.

Not only are groups of the tiny lights as bright as a fixture using incandescent bulbs, but they are cooler and will save the state millions of dollars in energy costs, not to mention thousands of hours changing bulbs. The new red lights, called light emitting diodes (LEDs), last 10 times as long as incandescent stop lights.

Caltrans commissioned the study and has decided to move ahead immediately with a statewide changeover of its 60,000 red light and pedestrian signals from incandescent to LEDs. Yellow and green lights may also be changed.

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