Traffic lights not picking motorbikes up?

r0zvad

r0zvad

r0zvad

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26 Dec 2003
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Was out on my CBR 125 getting some good practice in and multiple times in the night (1-2am) traffic lights just weren't picking me up at all. I've tried approaching them with full beam, flashing my lights, reversing and approaching again but nothing worked.

I figured it could be because my bike only weighs 120kg wet and me 57kg, since the sensors don't seem to react to my lights, do they work by weight? Also, I was waiting (experimenting ;) ) at a set of lights for 2 minutes or so, soon as a car pulled up, they turned green.

How the hell do I get lights to turn green! :p
 
a lot of 'lights work from pressure sensors in the road - look for the "rectangular boxes" just prior to the lights, admittedly a tad difficult to spot in the dark! :D

I've always thought the flashing of head lights at traffic signals to be something of an urban myth, I'd like a definitive answer... :)
 
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When I lived in Perth and used a rubbish scooter to get around I often had the same problem. It was a good thing .WA's traffic authority put handy lines on the road to show where you had to stop to get picked up by the sensor. I'm not sure if they use the same system back in blighty but the ideal spot to stop is on the seam that runs right through the center of the sensor box.

Basically try to stop dead center in the lane and about a meter back from the stop line.
 
R420LA6X2/4MNA said:
a lot of 'lights work from pressure sensors in the road - look for the "rectangular boxes" just prior to the lights, admittedly a tad difficult to spot in the dark! :D

I've always thought the flashing lights at traffic signals to be something of an urban myth, I'd like a definitive answer... :)
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it depends on the system used to detect cars etc. If its a sensor above the traffic light flashing may work, but if its pressure sensors in the road it will not. Also some lights are just on set sequences so nothing will get them to change.

Road works traffic control signals often change when you flash them, just got to bare in mind there's a set gap from the other one turning to red to yours turning green, it wont instantly change to green ;) Works for me.
 
Wait 5 minutes then proceed with caution, happens all the time, even on a bike bike ;)
 
R420LA6X2/4MNA said:
a lot of 'lights work from pressure sensors in the road - look for the "rectangular boxes" just prior to the lights, admittedly a tad difficult to spot in the dark! :D

I've always thought the flashing of head lights at traffic signals to be something of an urban myth, I'd like a definitive answer... :)
Click to expand...

On the A34 at Smallwood (near Alsager/Rode Heath) the light 9/10 times do not change unless you flash as you approach.
 
Yea happans a lot, during the day its less than 2 mins untill a car comes along but at night usually wait 5 mins then go with extreme caution!
 
I have the same problem and my bike is a 240Kg lump with a steel frame, so getting a 'real' bike won't help much.

Its because the lights use hall sensors under the road (detect the presense of metal above the road - not pressure) and a bike is simply too small to trigger the sensors. there are some that are worse than others, and for those you just have to hope you never come across one that has a red light sensor on it too so you can "run" the red, or wait for a car.. or find an alternate route.

Flashing of headlights works for lights that have the little cameras on the top.. not sure how they work.. i guess they are infrared sensors.. usually find them on temporary traffic lights and lights that have pedestrian crossings on them.
 
A junction near me is terrible for this, okay during the day as a car could come along with in a minute; but at night it's take another route or be stuck for 5mins...
 
They will either have a sensor built into the road surface that detects the weight of the vehicle or a sensor that is on the top of the lights, note these work by sensing the car by infra red and not by light so flashing your lights wont make a blind bit of difference to them.

People who say they only change when they flash probably means that those set of lights have a longer delay between one changing from green to red and the other changing from red to green.

What whould happen if there was a pedestrian crossing on green and you aproached flashing your light is it going to let you go and thus squish some innocent children.....I dont think so.
 
Felix Da Housecat said:
They will either have a sensor built into the road surface that detects the weight of the vehicle or a sensor that is on the top of the lights, note these work by sensing the car by infra red and not by light so flashing your lights wont make a blind bit of difference to them.

People who say they only change when they flash probably means that those set of lights have a longer delay between one changing from green to red and the other changing from red to green.

What whould happen if there was a pedestrian crossing on green and you aproached flashing your light is it going to let you go and thus squish some innocent children.....I dont think so.
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Yes it does work, are you trying to say that headlights don't emit IR in quite large doses?
 
Well... I heard that the flashing the lights "trick" was something that was programmed into some lights to give priority to emergency vehicles :confused:

Not sure that I buy that and the only people I've known to do this are mini cab drivers :p
 
lordrobs said:
Well... I heard that the flashing the lights "trick" was something that was programmed into some lights to give priority to emergency vehicles :confused:

Not sure that I buy that and the only people I've known to do this are mini cab drivers :p
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As for the emergency services I thought they used an electronic system where it either put them all on red or changed the light needed to green, otherwise you would have everyone and his dog flashing whilst at the lights. :D

I've only seen cab drivers flash and I read on another forum that the light thing was a myth as they had asked a repair/maintenance guy about it and it turned out they were not light sensors.
 
Felix Da Housecat said:
They will either have a sensor built into the road surface that detects the weight of the vehicle or a sensor that is on the top of the lights, note these work by sensing the car by infra red and not by light so flashing your lights wont make a blind bit of difference to them.

People who say they only change when they flash probably means that those set of lights have a longer delay between one changing from green to red and the other changing from red to green.

What whould happen if there was a pedestrian crossing on green and you aproached flashing your light is it going to let you go and thus squish some innocent children.....I dont think so.
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Useful statement of the day:

These aren't pressure sensors in the road for traffic light approaches, they are induction loops (http://auto.howstuffworks.com/car-driving-safety/safety-regulatory-devices/question234.htm) and therefore detect magentic field of the actual vechicle rather than the weight of it.

A motorbike (and push bike) are simply too small / don't have enough road surface area to detect a suitable change in induction hence are ignored! You could try attaching a REALLY large magnet to the bottom of your bike? :p

/Useful statement of the day
 
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