There is a set of lights near my home which are obviously on a timer as I can be sat at a red light with no other vehicle in sight - even in the early hours when there is almost no traffic. It would be better it the lights were not active during such times, the 'give way' system would be far more efficient.
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Traffic lights near us along the main road - theres about 7-8 sets within 1 mile. They all have their little green boxes at the roadside, but they are all connected to a BIG green box in some shrubs.
Each set of lights has a number of inputs: the original timing of each phase, the pedestrian crossing buttons (which may or may not have any effect on the lights, depending on the layout of the junction*), the induction loops in the ground, and some have the detectors on top of the red light.
All these feed into a computer, which calculates the timings for each phase, and also tells the other sets of lights what it is doing.
Therefore, if you get stopped at one set - for no apparent reason - it may be because the next set of traffic lights has turned red to let traffic out of a side road or let pedestrians cross - turning both sets red means traffic cant back up and block junctions.
*Some of the lights have a natural part of the cycle where pedestrians can cross the main road, so whether they press the button or not, the lights still change at the same time. Other traffic lights - you have to catch at just the right time to press the button, otherwise it makes you wait about 3-4 minutes (an entire cycle) before it will give you the green man.
Same as some of the right-turn lanes - they are sensor controlled, so if you drive up to the red light at the wrong time (just before it WOULD have changed had you got there 5 secs earlier), it makes you wait through the entire cycle, and your sat there in your car looking like a lemon, thinking it hasnt realised you are there. Tempting to reverse back over the loop for confirmation!!!
Each set of lights has a number of inputs: the original timing of each phase, the pedestrian crossing buttons (which may or may not have any effect on the lights, depending on the layout of the junction*), the induction loops in the ground, and some have the detectors on top of the red light.
All these feed into a computer, which calculates the timings for each phase, and also tells the other sets of lights what it is doing.
Therefore, if you get stopped at one set - for no apparent reason - it may be because the next set of traffic lights has turned red to let traffic out of a side road or let pedestrians cross - turning both sets red means traffic cant back up and block junctions.
*Some of the lights have a natural part of the cycle where pedestrians can cross the main road, so whether they press the button or not, the lights still change at the same time. Other traffic lights - you have to catch at just the right time to press the button, otherwise it makes you wait about 3-4 minutes (an entire cycle) before it will give you the green man.
Same as some of the right-turn lanes - they are sensor controlled, so if you drive up to the red light at the wrong time (just before it WOULD have changed had you got there 5 secs earlier), it makes you wait through the entire cycle, and your sat there in your car looking like a lemon, thinking it hasnt realised you are there. Tempting to reverse back over the loop for confirmation!!!
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