Saturday, February 16, 2008

The Problem With Traffic Lights

"'See, I can time them perfectly,' the [traffic] light said with satisfaction. 'I get hundreds of them each day. No one gets through my intersection without paying his tax in gas and rubber.'"

"'Go blow a bulb!' the car growled at the light.

"'Go soak your horn!' the light flashed back."

- from pages 187 to 188 of "Centaur Aisle," by Piers Anthony

I've had this quote in my "Quote du Jour" for several weeks, ready for the day I finally rant about traffic lights.

In my town, traffic lights are installed indiscriminately as a feeble response to town growth. The rich folks flock to buy McMansions in new developments. Then they complain that they can't get onto the main road without waiting a minute or two for a break in the traffic. So up goes yet another traffic light.

There are intersections where traffic lights are needed, such where two main highways intersect.

But why install one at a "T" intersection on a busy main road for a tiny side street? Here's why it's not a good idea:
  • If the number of cars on the main road is so great that you need to interrupt the flow in order to let yet more cars on it, you're contributing to yet more traffic congestion.
  • It's inefficient to force several cars to stop for the sake of one or two cars that are already stopped. Forcing a car to stop and then accelerate back up to cruising speed is a significant waste of gas. In fact every time a driver applies the brake, he or she "throws away" the fuel that was used to accelerate the car. And acceleration is what uses the most fuel.
  • Many of these intersections are so small that when cars turn onto them from the main road, the cars trigger the Hall effect sensor that causes the light to cycle. Thus, the light turns red for those who navigate the main road even when there's no car to yield to! More waste!
  • Finally, traffic lights waste electrical power all day and night. In fact, they remain powered up even in the wee hours of the morning when no one needs them. At night they're so bright you could read a large-print book under them. Why not reduce the light intensity after dark and save money? True, some lights are set to blink red-yellow, and thus they require half the electricity to light the lamps. But the controllers that run them also waste electricity. So just shut them down completely and get that power consumption down to zero. Drivers know anyway to stop before they enter a main road in the absence of traffic control.

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