lol @ Earthwind - you're right though, traffic signals can make you colour blind, it's the electrical radiation that does it.  It's also the reason why men shouldn't spend too much time waiting at traffic lights, because the radiation can make them infertile.

This is why, when you see men working on the highway near new traffic lights, they are often switched off.                                                                                                                                                                             

lol ahhh I alsways wondered and now I know, lol you all have it so hard I didnt realsie to what extent (sorry about the spelling) lol
                                                                                                                                                                             

"you all have it so hard"

Not when we're stood by traffic lights lol!                                                                                                                                                                             

Thanks Bikeabill, just bought the Traffic light sensor from ebay. I hope it works!
                                                                                                                                                                             

Right ... no one's really biting lol, so I'll tell you all the truth about traffic signals and in particular signal detection equipment.

I must say, the "solutions" I've read on this forum are one's I've never heard of before, but googling them shows that many people believe these urban myths as well.  I guess that although funny to a highway engineer lol, if you don't know, then you just don't know!

Induction Loops.

The square shapes you see on the approach to signals are not pressure pads, although these did used to be used in certain situations, such as lorry parks.  However, their maintenance costs and the fact that a large bare metal plate didn't offer a lot of skid resistance led to their demise.

The ones you see in the road are simply saw cuts filled with bitumen.  Laid in these saw cuts are loops of wire which feed back to the signal controller.

The way Induction Loops work is that the controller sends a small current along the wire, which because it is looped several times, creates a very small electro-magnetic field.  When a vehicle passes over this loop, the mass of metal disturbs this field and in so doing alters the voltage in the loop very slightly.  The controller registers this change in voltage and as such knows that a vehicle is approaching, waiting at or even leaving the signals.

The issue with some smaller motorcycles, is that there simply isn't enough metal mass to disturb the field sufficiently.  The controller can be adjusted to take into account a smaller disturbance, but only so far, as otherwise it would detect nearby guardrailing, lighting columns etc.

Bikeabill's traffic sensor should theoretically work.  These are nothing more than small neodymium magnets which are sometimes used by signal engineers to check that loops are working ok.  Be careful with these though as, although very small, they are quite powerful magnets and will easily destroy your credit card, computer hard drive etc!

Another option is to actually ride along a longitudinal cut, rather than through the middle.  This will have more effect on the electromagnetic field.

Yet another is to simply put your bike on its side stand.  By doing this you lean the bike over effectively widening the area of metal being detected by the loop.  This explains the reason some find getting off the bike and jumping up and down does the trick.  The jumping up and down does nothing other than amuse other road users (I'd suggest next time you actually dance for greater applause), it is the putting the bike on its stand before getting off that is doing the triggering!

Some good news.  This is an issue that authorities have clicked onto.  More and more therefore are now installing diagonal loops.  These have no benefit at all for most vehicles but because the loops run diagonally across the road and normally are shorter as well, there is far more chance of a small vehicle, such as a motorcycle, sitting across at least two wires.  This increases the disturbance of the field.

(See!  We do think about bikers!)

Microwave Detection

The little boxes on top of a lot of signal heads are not cameras.  These are microwave detection units.  Flashing your headlight at them has as much effect as flashing a torch at your microwave to speed up the defrosting of your chicken lol!

Actually, the microwaves emitted by traffic signal detectors bear little resemblance to the microwaves used for reheating last nights curry.  As such people don't need to worry about the risk of being fried by these things, they are harmless.

Indeed they are nowadays also used to detect pedestrians at crossings such that the controller knows to lengthen the green man time if an elderly person is taking three years to cross the road or whether someone has pressed the button and then changed their mind and walked away.

"Microwave" simply refers to the high frequency of wave used.  The advantage of a high frequency wave is that it can be directed towards a relatively small area and still get a strong return signal.  The detector emits a pulse and then measures how long it takes for that pulse to be returned, thereby knowing where a vehicle is.

Both forms of detection can be used for both waiting vehicles and by means of a series of loops or a microwave detector, for detecting approach speeds.  The latter allows the controller to be able to adjust the "intergreen time" between one flow being stopped and the next getting the green light, thus reducing the chances of conflict caused by drivers "running" a red light.

They are also sometimes used to link signals.  A detector on the exit from a set of signals allows the controller to know how many vehicles are leaving and it then sends a message to the next set of signals, usually via a phone line.  The controller here then knows in advance whether it needs to adjust signal timings or not.

Other Forms Of Detection

There are other forms of detection out there, such as magnetic detectors, HIT (High Intensity Light) and even video detectors.  But generally apart from a few specialist applications, these are more costly and no more reliable than induction loops and/or microwave detectors.  As such, they are very rarely used on the highway.

I hope this lot helps.  If anyone has any questions ........ google is your friend lol!                                                                                                                                                                              

  Excellent info, thanks Geoff                                                                                                                                                                              

Cheers guys n gals some great info there And at least now I know I don't have to dance about in the street ...                                                                                                                                                                              

so how come it doesnt work on certain traffic lights then when u are on a bike

oops read it again thats why when i move the position of my bike am cutting across the trigger thanks :)
                                                                                                                                                                             

Just be aware Earthwind, that my "tips" aren't totally foolproof.  At the end of the day if your bike doesn't have sufficient metal mass to trigger the loop, then you'll be sat there forever lol!                                                                                                                                                                             

i dont believe it. i sit there and flash my lights and they deffo turn green for me. okay, it might take 5 minutes of flashing my lights, but it makes em turn green. how can that be an urban legand?                                                                                                                                                                              

I don't think I would sit at a set of traffic lights for 5 minutes flashing my lights to see if it is going to change - I would be sat at a red light for about a minute at the longest - after that, as far as I'm concerned, they aren't working properly (in not detecting me being there) so I just go though (see the highway code post above).                                                                                                                                                                                 

As tcat says, five minutes without changing and you've got a problem.  Signals tend to work on a set cycle based upon a 60, 90 or 120 second programme, with the latter being uncommon.

Many also have priority overrides as well, so if you have a major route and a minor route and the minor route isn't being used, then the major route will remain on green.  Although not always as there are other reasons for stopping traffic other than to simply allow a joining link to get a green.

However, these systems with a priority override will still give the minor route a green light occasionally, even if no traffic is detected.  This is specifically to take into account the likes of cyclists and small motorcycles that may not be detected.  This green light may come on once every two cycles, so perhaps as long as once every three or four minutes.

Trust me DD, they're microwave detectors.  Flashing your headlights has no effect.                                                                                                                                                                             

lol geoff my bike is a triunph spriny are u casting aspersionslol 

:)
                                                                                                                                                                             

Hey does this mean I get the green light for my idea Geoff brilliant I got somthing right at last                                                                                                                                                                             

You ride a Honda Bill, you do something right every day mate lol!
                                                                                                                                                                             

"geoff my bike is a triumph sprint are u casting aspersions lol"

Erm, no, Earthwind.  When I said small motorcycles, I didn't actually mean small motorcycles, but rather those smaller than a bus lol!  A classification within which mine does not fall lol!!



Phew ... saved that one I think lol!

                                                                                                                                                                             

only just lol :P                                                                                                                                                                              

 have a confession to make Geoff, i'm just building up a Triumph engined thing, but will keep one of my Fireblade
                                                                                                                                                                             

Oh Bill .. what are you doing lol?

lol @ "Triumph engined thing" .. knowing you mate, this could be anything lol!                                                                                                                                                                             

dont now about that Geoff but it's costing a fortune