Most led traffic lights operate on computer-driven system
 

　　Ever wonder what speed you would need to drive on a city street in order to make it through led traffic lights without stopping? Ever wonder why you can be the only car stopped waiting at led traffic lights intersection and the light won't change green? As it turns out, it's not based on luck. There's actually a science behind it.

　　Like most sciences, it's a highly specialized field with a lot of technical jargon and sophisticated systems to make it all work, efficiently and safely. Traffic engineers have toiled for years to perfect traffic signal project in order to control the right-of-way for vehicles arriving at intersections, reducing traffic delay and other accident-producing conflicts.

　　Indeed, there are many benefits to led traffic lights management systems. The more technologically advanced systems offer the most benefits, such as intelligent traffic signal controller, fewer cars stopped at red lights can reduce idling emissions; and by allowing big rigs to pass through intersections without stopping also help the environment. Traffic light timing generally results in fewer rear-end accidents. And best of all, everyone can get to where they're going quicker and more efficiently.

　　The first automatic traffic signal project — using red, amber and green railroad lights — was installed in 1920 on a busy corner in Detroit. Within several years, many other major U.S. cities began to install these signals. Back then, traffic lights worked with moving gears (like that of a clock), clicking the lights on and off.

　　Today, most signals operate from computer-driven controls that allow for increased flexibility in keeping a green or red light turned on for a specific length of time. Most can respond to the number of cars entering the intersection from different directions. In short, these signals are not blind; they can 'see' cars through one of three ways: through radio waves that can be bounced to detect moving objects; cameras; or through sensors that are strategically placed under the pavement. The latter is the most commonly used.

　　The intelligent traffic signal project that monitors these signals (waves, camera or sensors) are housed in a four- to five-foot tall control box, usually positioned near the intersection. When cars continuously go through an intersection, it keeps triggering signals, indicating that the light should remain green. When the triggers stop firing, it means there are no more cars and the light should turn red.

Intriguing. Truly.

This has been the case since the 1990s in most of the first world. Most long roads with lights are synchronised so a car travelling at the speed limit will hit greens, while speeding will result in having to slow down or stop.

I found that the signals on NASA 1 are synchronized to about 53MPH, and the speed limit is 45. I vote Webster, Texas for worst-programmed lights.

Also, strange that a new user with "trafic" in his/her username would make one post about traffic signals in an unrelated forum and dissappear.