How to traffic lights work?

Always wondered. I've heard SO many stories about how they manage the traffic.



- Cameras

- Sensors under the road

- Timers



Honestly, I've been curious about them ever since elementary school, but never bothered to ask.How to traffic lights work?
It's a combination of timers and sensors. Some just change at set intervals while others also use sensors to determine whether there is heavy traffic flow and such to determine when to change.



There are cameras on some traffic lights but these are generally used to pick out people who run red lights, as well as manually gauge the traffic flow.
my dad told me that they have special censer plates under the tar, that can tell if there are cars there waiting to go in a different direction, when there is no more cars coming, the censer plates can tell obviously as well too, and switch the lights... sorry that was probably really confusing.. also they do have timers obviously, you know when there is a LONGGGGG mile of traffic? well they cant go through that whole line at once, its like going back to kindergarten, and taking turns.How to traffic lights work?
depending on where you live or more less what area of the city you are in it will vary. if you live in the same place for quite some time then you can tell if you pay attention what lights run on what system. if you ever want to find out ( or speed time up ) come to a red light. stop there for a brief moment then make sure there is no one behind you and back up about two car lengths, then pull forward back to the line. the light will switch pretty quick because the sensor cant tell that you backed up. it can only tell that "more cars came". and if there is a camera, its pretty obvious, all you do is look up to where the stop lights are connected and tada they are small but not that small. most are placed at angles so check corners because they have stop lights on your side as well as in front of you. some radar detectors can pick up traffic cameras btw
Many street lights are equipped with Traffic Signal Preemption systems like the 3M Opticom or the Tomar Strobecom. These systems enable emergency vehicles to change the traffic signals from Red to Green, and to change the traffic signals for others from Green to Red. This enables emergency vehicles to travel more quickly and more safely.And also it helps to clear heavy trafficHow to traffic lights work?
The most common technique is the inductive loop.



An inductive loop is simply a coil of wire embedded in the road's surface.



To install the loop, they lay the asphalt and then come back and cut a groove in the asphalt with a saw.



The wire is placed in the groove and sealed with a rubbery compound.



You can often see these big rectangular loops cut in the pavement because the compound is visually obvious.
timers. they do have cameras and sensors though. but they are for people who chose to run red lights. when the light turns red, and they still go, a sensor sets off the camera, taking a picture of your license plate. or some cameras are on and recording 24/7
This should explain it to you...



http://auto.howstuffworks.com/question23鈥?/a>



It breaks it down with examples and everything..
2minutes for oneside and then red light and opposite 2minutes then red light over and over again
some are on timers, others have sensors...check out the website below and get more details.
sensors ive heard



i think its timers during the day, but im not sure now bcos at night if theres noone on the road coming from one direction, the other TL stays green



D:
its just timers nothing more just timers oookkkaaayy(retard)
Some use sensors and some are timed, it can also change depending on the time of the day.
timers to switch. then they monitor them so the time matches the traffic conditions
they have e lights, red...stop , yellow ..slow down.. green go
Timers I think.
its timers i do believe.
all the above is correct