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AdamW said:
In this case, don't you mean Green Ken?
Traffic Lights.
- Thread starter mildmanneredjanitor
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In this case, don't you mean Green Ken?
B
breezer
the boxes you refer to are microwave detectors, not all traffic lights have them, most use inductive loop
B
breezer
i know you are taking the mick, but i shall explain for those who dont know.
a microwave detector uses the dopler shift principal (like fire engine siren "changes" but you know it doesnt really) to decide if a vehicle is moving towards or away from it. It send sout microwanes and these bounce off the object in quiestion, depending on rate of relection determines if object is going towards or away
The other method of vehicle detection is the induction loop, but this can only say if something is there or not (NOT what it is, as some one thinks)
I just did some checking (as you you do) i already knew trafffic lights can "see busses" in London there are special bus lane junctions (not just bus lanes) that are controlled by traffic lights, when bus approaches lights change, this is called
Microprocessor Optimised Vehicle Actuation (MOVA) it has been around for years, but is unrelaible because it holds traffic lights on green too long, causing more hold ups than it solves.
Recently they have made a new chip that will make MOVA work properly, but it still uses induction loops(not microwaves on top of lights) it does give priority to police cars etc, but it is still not yet 100% reliable, so police and fire engines still drive on the wrong side of the road
a microwave detector uses the dopler shift principal (like fire engine siren "changes" but you know it doesnt really) to decide if a vehicle is moving towards or away from it. It send sout microwanes and these bounce off the object in quiestion, depending on rate of relection determines if object is going towards or away
The other method of vehicle detection is the induction loop, but this can only say if something is there or not (NOT what it is, as some one thinks)
I just did some checking (as you you do) i already knew trafffic lights can "see busses" in London there are special bus lane junctions (not just bus lanes) that are controlled by traffic lights, when bus approaches lights change, this is called
Microprocessor Optimised Vehicle Actuation (MOVA) it has been around for years, but is unrelaible because it holds traffic lights on green too long, causing more hold ups than it solves.
Recently they have made a new chip that will make MOVA work properly, but it still uses induction loops(not microwaves on top of lights) it does give priority to police cars etc, but it is still not yet 100% reliable, so police and fire engines still drive on the wrong side of the road
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kendor said:
Kendor,
take a closer look at the picture....
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Not pointing any fingers...
They were, I used to go through there regularly as a kid (as a passenger of course) on my way to see my sister. Most reliable part of the whole journey. North circular used to take about 2hrs! Essex to Swindon about 4 1/2 - 5hrs.
induction loops for emergency vehicle, might have been an idea once. Emergency vehicle in London never get near to lights to change them (the ques are so long ) they just go wrong side of the road & turn across the traffic. It seems to work. Far better than trying to inch over when you are queuing at lights.
B
breezer
thats what i was saying, (thank you) and of course now if there is a fire engine coming up from the rear and you are at the front by the line at a red light, are you going to move forwrd so the fire engine can get through? are you really because there is a "red light" camera sitting at the lights, you drive over the line (into another induction loop) and flash you get your picture taken and can you prove there was a fire engine coming ? course you cant, so i ask again are you going to move?
Dont worry it is accepted that you wont and it is often quicker any way if a fire engine does cross and go the wrong side of the road
Dont worry it is accepted that you wont and it is often quicker any way if a fire engine does cross and go the wrong side of the road
Diyisfun said:
I have seen them cross centre dividers with quite big kerbs... A Vauxhall garage told me they sell most of their Astra hub units to the Police maintenance guys, obviously due to all this kerb mounting!
Would a traffic light camera flash if you were on the wrong side of the road? I mean, surely the detectors are set up directionally. They probably would, the field of view is no doubt set up to cover the whole junction and you get some extra points for dangerous driving!
There is a set of bus-controlled lights at Marble Arch, the buses cut through the middle of the roundabout. I believe they have this in Australian cities too, for the Road Trains (too big to circumnavigate).
kendor said:Do we really need Traffic lights? we could go back to the gentlemanly days of yore and rely on each others good manners to let the other chap go firstnow that would be fun!
I think we should bring back the red flag but allow the holder to run. That way the faster runner you can afford the faster you can drive.