In this amazing age, when everything from cars to coffeemakers has brains that make them smart, why are traffic signals still so damn stupid? Every day, we resignedly herky-jerk our way through a gauntlet of ill-timed or just plain unnecessary traffic lights. They’re so ubiquitous in the built world that you may not even think about them anymore–yet they’re an integral part of your daily urban and suburban experience. You probably spend more time idling at traffic lights than you do eating your breakfast.

No one would quibble with the need for traffic signals at complex, busy intersections. But there are also plenty of signals installed in places that don’t need them–an inane, wasteful, yet widespread practice. What’s more, many of the intersections that do need signals don’t just have a light for each direction, but a whole phalanx of redundant ones over every single lane. No doubt this kind of overkill is every signal salesman’s dream. But are we motorists really so stupid that we need four simultaneous green lights to know it’s our turn?

One thing is certain: Despite the huge numbers of people they affect, traffic signals are far dumber than most any other piece of technology in common use. How many times has a lame-brained signal kept you waiting at a red light, your car’s engine wasting fuel and pumping out pollution, while there wasn’t any cross traffic within half a mile?

This situation isn’t trivial when it’s multiplied by the countless badly regulated intersections in America. But don’t take my word for it: Here’s what one unusually sensible public works department–that of Arlington, Va.–has to say about it:

“Installed under inappropriate conditions, a traffic signal is ineffective, inefficient, and a potential danger to motorists and pedestrians. Signals that are installed when no legitimate need exists often generate an increase in vehicle stops, traffic delays, fuel consumption, traffic accidents, and motorist disrespect for other traffic signals.”

But the traffic signal industry is a vast one, and given the average traffic engineer’s proclivity to plant signal poles like dandelion stalks, its market is virtually guaranteed. Far be it from me to begrudge these companies their fair share of the public coffers. But I do begrudge the fact that, while they’ve diddled endlessly with hardware such as lenses, masts and shrouds–the better to shame cities into “modernizing” their installations at great expense–they’ve done next to nothing to improve the way signals actually direct traffic.

America’s first traffic signal was installed in Cleveland, Ohio, in 1914; it used the illuminated words “STOP” and “MOVE.” Around 1920, a Detroit policeman named William Potts came up with the familiar red/yellow/green signal. Since that time, there’s been no fundamental improvement in the way signals work. In fact, these early signals were probably smarter than most modern ones–they were operated by a man in a sort of elevated phone booth overlooking the intersection. He decided who came and went based on the traffic flow at that moment.

Today, the very latest in signal controls is a system called SCOOT (“split cycle offset optimization technique,” in case you were wondering). Its manufacturer, the mighty Siemens, bills it as a “dynamic, online, real-time method of signal control.” In other words, it works just like that guy in the glass booth. And it only took them 85 years to come up with it.


What’s your opinion? Send your Letter to the Editor to

Show Comments Hide Comments


Sign up for Inman’s Morning Headlines
What you need to know to start your day with all the latest industry developments
Thank you for subscribing to Morning Headlines.
Back to top