The lowly traffic signal. We barely notice when it�s green, we race when it�s yellow, and we curse when it turns red. But stoplights have undergone a quiet revolution in the past few years. The ubiquitous controllers now come packed with brighter displays, digital camera equipment, and smart software — all designed to unclog urban arteries and automatically ticket drivers who run reds. If only they could put a stop to road rage.
STOPLIGHTS THAT KEEP TABS ON TRAFFIC – AND OFFENDERS
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Mike Lorrig; EconoLite; Victoria Police; US Traffic Corporation
Timing Is Everything The secret to keeping traffic flowing at its peak: math. For instance, a software program called Transyt-7F runs up to 10 signal-timing plans through a computer model, then pits the better scenarios against randomly mutated versions. It analyzes the mutations across dozens of intersections in an urban grid until it finds the best plan. The result: timed signals that let cars sail through green lights at every intersection — if they go the speed limit.
Brighter Ideas Across the country, cities are replacing traditional incandescent bulbs with LEDs, which are 15 to 20 percent brighter, consume 80 to 90 percent less energy, and last five times as long — a minimum of five years. The Federal Highway Administration is reviewing an even more radical signal: The Unilight, a single signal that changes color and shape to indicate stop (red octagon), caution (yellow triangle), and go (green circle).
Captured on Video Forget about driving back and forth over detectors to trip signals. Digital video cameras can now spot vehicles and pedestrians, track their speed and direction, and trigger green lights. The cameras have processors that analyze footage in real time and output the results onto 640-Kbyte flash cards. The results can later be used to fine-tune signal timing and traffic flow.
Smile, That�ll Be $200 Videocams aren�t the only digital shooters on the scene. New hi-res still cameras are being used to catch red-light runners. Photos of your hot-rodding are mailed with your ticket. In theory, police could �take your picture as you run a red light and fax it to your car before you drive a block,� says traffic-photo consultant Jimmy Stephens. Fewer than 10 cities have installed the technology. We suspect even fewer cars have a fax machine on board.
New Chips on the Block Those ugly steel boxes on street corners aren�t just for graffiti. They actually house microprocessors that, with the help of 100,000 lines of code, switch lights from red to green and back. Why all the programming? The controller not only handles every signal at the intersection but also allows a city�s traffic operations center to monitor and adjust the timing of each light on the fly.
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