Busting Traffic Light Myths - Or - Why Can't I Get A Green Light?

by: Eric Scribener


On December 10th in the year 1868, the first traffic signal light was placed into service. The bulky, primitive device employed colored lamps that were fueled by gas for use after dark, and semaphore arms. It required an operator to attend it at all times that it was in use. Twenty three days after that first traffic signal light went into service, it exploded – injuring the police officer who was assigned to run the lights and signals. This unfortunate event brought into question the practicality of implementing traffic signal lights.

Despite the volatility, and ultimately disastrous results, of using the first traffic signal light, stalwart inventors and engineers pursued the idea. As more and more traffic amassed on streets and roadways, the use of stop signs and officers standing on boxes at intersections became less and less practical – and more and more dangerous.

Sometime around 1912 the first electric traffic signal was put into use. These initial units only had red and green lights, however. In 1917 in Salt Lake City, Utah, a series of traffic lights were linked together, thus 'connecting' six sequential intersections. This system was operated manually with a single switch.

In 1922 Garrett A. Morgan made application for a patent on a traffic signal light of his own design. The patent was granted the following year. This started the myth that Morgan was the inventor of the traffic light.

Between the time the first traffic lights were introduced, and the early 1960's many improvements were made, and many experiments conducted. The biggest problem with traffic signals to that point was simply that they were dependent on timers only. East-west traffic would get a green light for 3-minutes, and then a timer would trigger a green light for the north-south traffic – and so on. The lengths of time could be adjusted, but these settings frequently created problems with the flow of traffic.

In the early 1960's traffic engineers started to implement "inductive loops" to control intersection traffic flow. The loops, which could detect vehicles in specific lanes at intersections controlled the lights' timers. The inductive loops would switch the lights to accommodate the traffic at hand, based on the time of day. No more sitting at red traffic lights for 2-3-4 or 5 minutes - even if there was no cross-traffic present. Traffic engineers basked in a deluge of praise from drivers.

In the 1970's technological advances in metallurgy, plastics, and rubber started changing the way vehicles were manufactured – and what they were being manufactured with. No longer was everything from the dashboard to the fenders made of high-iron content steels. It was in conjunction with these advances that the myths of tripping traffic lights began. Since then, it has gotten worse every year as more alloys, plastics, and rubber are used in the construction of vehicles.

It seemed logical that the amount of weight present at an intersection is what would trigger a green light. This is a myth. It also seemed logical that the mass present at an intersection would trigger a green light. This is also a myth. Since people were unable to make traffic lights trip by adding weight, or by having more mass to their vehicles, they started to seek other answers. The last most popular myth is that there is an invisible curtain that, when broken by a vehicle, triggers a green light. It is thought that the curtains only cover a portion of the lane, and if you do not violate the curtain, you don't get the green light. This is also a myth.

Actually, inductive loop technology is very simple. An inductive loop is nothing but a very large, very weak electromagnet. The term 'inductive loop' refers to electromagnets used in industry to detect iron. They are commonly used in numerous industrial applications. They are inexpensive to make, install and maintain.

Inductive loops at traffic lights are created by burying large coils of thin copper wire slightly beneath the road's surface. The wires are covered with either black tar or rubber. A small current runs through the wire, thus making it into an electromagnet. The loop is connected to a meter which measures changes inside the loop. Magnets react to iron – not plastic or rubber or aluminum. So when enough iron is present within the loop, the traffic light cycles to green.

The vehicles that have the greatest trouble tripping lights are motorcycles and mopeds, followed by small cars and trucks, and then raised 4x4s and SUVs. Drivers of these vehicles often sit undetected at traffic lights wasting fuel, getting rained on, their engines overheating, and their irritation growing.

To positively trigger your green lights, you can drag a bowling ball-sized piece of iron around on the ground – but that won't work if it's inside your trunk. That's too far from the weak sensing field of the loop. In the trunk, you'll need two or three large iron balls. OR you can install a Signal Sorcerer® traffic light changer http://signalsorcerer.com/.

Signal Sorcerer® traffic light changers use their own technology to make inductive loops detect your vehicle – no matter what size, weight, or mass it is. Simply install the Signal Sorcerer® under your vehicle, and the inductive loops that control traffic lights will detect your vehicle, and give you the green light!

Signal Sorcerer® requires no power, lasts a lifetime, is legal everywhere, installs in less than five minutes without any tools, and is completely guaranteed. Signal Sorcerer® traffic light changers have been in use around the world for years, and units are available for every application including police motorcycle divisions, security vehicles, fleet vehicles, and personal conveyances.


About The Author

Eric Scribener is a 30-year veteran freelance writer and photographer currently on assignment for http://www.dotcomtucson.com/ - putting Tucson Arizona in the palm of your hand.