Noticed over the last week or so on the early starts that a couple of vehicles, cars and trucks included pulling upto a red traffic light and they’ve been flashing headlights at the traffic lights, I remember hearing it when I first started driving 30 yrs back that if you did flash your lights it makes the traffic lights change.
I just thought that was some kind of old wives gubbins didn’t really think it was a real thing, maybe it’s always been happening and I’m just really not very observant.
Noticed over the last week or so on the early starts that a couple of vehicles, cars and trucks included pulling upto a red traffic light and they’ve been flashing headlights at the traffic lights, I remember hearing it when I first started driving 30 yrs back that if you did flash your lights it makes the traffic lights change.
I just thought that was some kind of old wives gubbins didn’t really think it was a real thing, maybe it’s always been happening and I’m just really not very observant.
Anyone do this then or
Ta
yeah I remember doing it. …does work on certain lights or like you say ‘early morning’.
An ambulance driver told me that some lights respond to blue flashing lights to give emergency vehicles priority, this was backed up by a copper as well, but only SOME lights, not all.
Don’t know if a flashing headlight will do the same, but obviously a few people believe it will.
Some traffic lights have a box above the red light. This box holds a photo electric cell ,when you flash it “can” cause the lights to change. I have been involved in setting up temp. lights at road works whilst doing tipper work.
The box on top of the older traffic lights is a P.I.R (passive infra red) sensor its a movement sensor and is not affected or influenced by light you find the same sensor on domestic security lights.
Flashing lights at them does nothing, the newer system has a grid of wires just below the road surface leading up to the junction usually three sets, these are connected to a computer which runs a suite of software called roadrunner or similar which learns traffic flows and volumes at certain times of the day or night and switches the lights accordingly.
Approach the lights slowly and if there is no traffic coming in the other direction that has reached the sensors before you the lights will change in you’re favour, its a myth that flashing headlight does anything.
Differential detection[edit]
Pairs of sensor elements may be wired as opposite inputs to a differential amplifier. In such a configuration, the PIR measurements cancel each other so that the average temperature of the field of view is removed from the electrical signal; an increase of IR energy across the entire sensor is self-cancelling and will not trigger the device. This allows the device to resist false indications of change in the event of being exposed to brief flashes of light or field-wide illumination. (Continuous high energy exposure may still be able to saturate the sensor materials and render the sensor unable to register further information.) At the same time, this differential arrangement minimizes common-mode interference, allowing the device to resist triggering due to nearby electric fields. However, a differential pair of sensors cannot measure temperature in this configuration, and therefore is only useful for motion detection.
Where I live there’s a dual carriageway with a centre filter lane with a set of lights for a right turn across the other side. You can see the outline of 3 sensors in the lane spaced about 50 feet. Often used to see taxis hanging way back in the line, well short of the lights even with no cars in front. A local taxi man said its a local cheat that if you sit on the last sensor or roll slowly across it the lights think the lane is full up and change to green. I’ve tried it when it’s dead quiet and it does work .
Noticed over the last week or so on the early starts that a couple of vehicles, cars and trucks included pulling upto a red traffic light and they’ve been flashing headlights at the traffic lights, I remember hearing it when I first started driving 30 yrs back that if you did flash your lights it makes the traffic lights change.
I just thought that was some kind of old wives gubbins didn’t really think it was a real thing, maybe it’s always been happening and I’m just really not very observant.
It is an old wives’ gubbins. Some permanent traffic lights have induction loops in the road surface to detect approaching traffic (very useful where there are filter lanes as they can easily identify which lane vehicles are using), some temporary lights have PIR detectors, many permanent and temporary lights use radar to detect queuing traffic (induction loops only really work with moving vehicles). None of them have visible light detectors.
But if it keeps drivers happy, let them flash away…
GORDON 50:
An ambulance driver told me that some lights respond to blue flashing lights to give emergency vehicles priority, this was backed up by a copper as well, but only SOME lights, not all.
Don’t know if a flashing headlight will do the same, but obviously a few people believe it will.
Edit… maybe they were not pulling your chain!! Apparently in the US, some towns, cities and states operate a “traffic signal pre-emption system” that allows approaching emergency vehicles to cause a red light against them to change to green via either an infrared transponder or a strobe frequency sensor on top of the traffic light. The strobe frequency sensor is linked / matched to the same frequency as the forward facing strobes on an approaching emergency vehicle. When the red light changes to green for the approaching emergency vehicle it automatically changes to red for other traffic flows. Could get a bit messy otherwise!!
So it could well be in use over here or at least has been trialled somewhere.
The old wives tale about flashing your headlights to make a red light against you change to green is just that, an old wives (or boy racers!) tale!
Tried it last week,and a young lady of the night appeared from the shadows and ask if there was anything she could do for me? I asked how much, she said a tenner, I told her I was skint,and she said that’s ok I will lend you it, sometimes I wish I was not a super trucker! Joepipe
I don’t think I’ve ever seen an ambulance slowing down approaching a red light, which then changes green ahead of it’s normal schedule.
It’s ambulances one sees overtaking any queueing traffic behind a red light, and they just go through the red light, getting flashed by any “amber gambler” speed cameras that might be there and all.
I’d have to concur that it does indeed seem like a myth, this idea of lights changing for emergency vehicles.
I used to work for M. P. Burke (for my sins) grab driver on an old knackered (Burke’s again) 8 wheel Merc. We used to laugh at cars flashing their lights at our traffic lights, cos the little box back at the top of the lights was a photo-cell as has been pointed out, but it responds to Infra-red - in other words engine HEAT not light - you can flash your lights all day long but it’ll not do 'owt. But this is only for temporary road works lights. Some of the new ones are a bit cleverer than that and can be put onto either timer, or sensor or manually controlled. On sensor they can also be set to respond to different volumes of traffic at a junction, say. Now when we come to static lights they are controlled by one of three systems, either UTC, (Urban Traffic Control), MOVA (Microprocessor Optimized Vehicle Actuation), or by SCOOT (Split Cycle Offset Optimization Technique). They use sensor loops in the road to provide them with traffic information. Which kind depends on where you are, which council, and how much money they have to spare! But all of these systems are programmable, they all have a means of optimizing traffic flow depending on time of day, and volume of traffic in any direction. All very clever stuff - and quite rightly some of these fixed sets can respond to buses and to emergency vehicles, giving them priority. Most of the traffic light systems (the software), certainly in Europe (but I don’t know about other places) are built by Siemens in Lincoln. I have a mate who programs the things, and he was good enough to provide me with the fixed light systems stuff for you all. Happy trucking y’all.
Joepipe3:
Tried it last week,and a young lady of the night appeared from the shadows and ask if there was anything she could do for me? I asked how much, she said a tenner, I told her I was skint,and she said that’s ok I will lend you it, sometimes I wish I was not a super trucker! Joepipe
That’s just plain crap as her previoua earnins would have already been spent on more crack …
Not particularly relevant,but in Spain there are many villages which have amber lights flashing which will turn to red if you exceed the stated speed limit.Locals also know that if you exceed said limit by a lot you will be passed the light before it can change to red!
.
