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signal changer

changes red lights to green as you get to them
(+2, -2)
  [vote for,

A few years back I noticed that if it was dark out and I was the only one at a red light, flicking my high beams off and on rapidly, would cause the light to change. Thinking that this was just a coincidence I tested it out on lights which had changed to red as I approached the intersection, and it turns these green as well. I think that there may be a system in place to allow emergency vehicles to more easily navigate the city, and that their bright flashing lights activate the signal changes.

Now, I'm not saying that we should be converting our high beams into strobe lights or driving at night would be chaos, but with a little experimentation a device might be built which uses light, not of the visible spectrum to make a high power strobe which would work even in daylight.

Smooth sailing... at least until everyone else has one.

emergency responce, preemptive signal changes http://www.doh.dot....su/SMS/emergpre.htm
[2 fries shy of a happy meal, Oct 19 2002, last modified Oct 21 2004]

Small blurb about strobe actuated signals http://www.ci.misso...ervices/cominfo.htm
[20 Oct 02] Traffic light info page from the mighty city of Missoula, Montana. [bristolz, Oct 20 2002, last modified Oct 21 2004]

SCATS link http://www.mrwa.wa....lications/scats.htm
And the SCATS link too [CrumbsDM, Oct 20 2002]

MIRT http://www.washingt...3Nov3&notFound=true
This has been baked, and they are for sale. [galukalock, Oct 05 2004]


       //allow emergency vehicles to more easily navigate the city//   

       If this were ture, then why are emergency services given the right to go through red lights?   

       Whats happening is that you are driving during an off-peak time, and so the lights change periodically to a set timer. This timer can be over-ridden however, if their is traffic on one of the roads. The traffic sensors at these lights would sense light. The light dimming and the brightening would be enoughto force the change, because it thinks (knows) that there is traffic.
[ sctld ], Oct 19 2002

       /sctld/ Your anno prompted me to get off my ass (not literally) and search for emergency vehicle preemptive signal changes. See link.   

       I sit corrected. (But i still stand by my annotation.)
[ sctld ], Oct 20 2002

       Not all signal lights have the strobe activation. Those that are on timers - are, for the most part in L.A. anyway, also activated by what I assume to be custard-filled-sensors. If the custard is squished - the light changes. Example: West L.A. - just below Brentwood has the best setup - driver approaching a green light which is changing to yellow - then sees light goes back to green again without ever seeing red doesn't have to wait...
thumbwax, Oct 20 2002

       Tufries: Ever noticed those little things on top of traffic lights (in the UK at least) - I'm pretty sure that they're light sensors (or the sorts of things you get at automatic doors), which detect whether or not there is any traffic. I assume that if it only picks up traffic on one of the roads, it changes that light to green.
And if it doesn't, it bloody well should.
NickTheGreat, Oct 20 2002

       [thumbwax] is on target again - custard pads are common in the UK too. [NtG], those things you mentioned are not to be talked about. I'd remove your anno before David Shayler's ex-buddies knock on your door with sledgehammers.
General Washington, Oct 20 2002

       Here in Canada, those little things on top of the lights, nine times out of ten are cameras, (big brothers' watching). The government was trying to implement sending tickets in the mail for those running a yellow light, or driving without a seat belt, or anything else that might help line their coffers, The liberal party, used abbolishing photo tickets as part of their platform to get into power. Now the little cameras just sit there waiting for the government to weasel out of its campaign promises.   

       I know that some intersections have either a weight sensor under the road or a motion sensor of some kind on top of them, but the flashing high beam thing seems to work regardless of what's in place.   

       "I replaced the headlights in my car with strobe lights. Now it looks like I'm the only one moving." -- Steven Wright.
calum, Oct 20 2002

       BBC Radio 2 DJ*? Or someone else?
*: Not that I listen to 2, I'm a Radio 1 man myself.
NickTheGreat, Oct 20 2002

       Not a weight sensor... an induction coil, the field of which is interrupted by the presense of large hunks of metal above it.
waugsqueke, Oct 20 2002

       I explained how traffic light systems are normally set up in Australia under "Bicycle Radar Reflector". In most cases you can set off the induction coils by minute motion of the vehicle. Sorry, waugsqueke but the simple presence of metal doesn't disturb the field, the metal must be in motion to generate an effect. I repeat part of my bike radar reflector comment here:   

       //as far as I know only induction loops are used in Australia. We have loops set up for cars -and- bicycles (but not both together). Generally the induction loops are only noticeable in effect during periods where the side road traffic is likely to be low (ie. at night). During the rest of the time the traffic lights are on a complex city-wide semi-synchronised system called SCATS (Sydney Co-ordinated Adaptive Traffic System). Note I'm not saying this is the system used elsewhere in the world. It is however used in parts of the US and Ireland.//   

       It is possible that some lights might use an air tube method but it's highly unlikely.
CrumbsDM, Oct 20 2002

       // Sorry, waugsqueke but the simple presence of metal doesn't disturb the field, the metal must be in motion to generate an effect. //   

       Yes, I neglected to mention this - I thought it implicit. The metal does not just magically appear in place.
waugsqueke, Oct 20 2002

       I recall some sonic devices used to change lights in Japan. A mechanism over the street directed ticking sounds down toward traffic; variations in reflection denoted traffic below.   

       They usually couldn't pick up a cyclist, unless you yelled.
lurch, Oct 20 2002

       Is that why my crazy Japanese cycling friend yells "Banzai!!!" every time we approach an intersection?...I just thought he was having a kamikaze moment.
jurist, Oct 21 2002

       I thought that the sensors at intersections here in Canada were weight sensitive after listening to many motor cyclists complain about the lights not changing for their bikes, just goes to show, you should never make assumptions, because you make an ass out of u and mptions.   

       I briefly looked around for enough info on induction to confirm this but didn't succeed. I seem to recall that the larger the mass of metal affecting the induction the greater the amount of current induced. Bicycles, therefore, don't normally set off the traffic light induction coils because they don't generate enough electrical current to pass the Traffic Control Systems timing threshold. This could be the case with motorcycles too, if the threshold is set too high.
CrumbsDM, Oct 22 2002

       The system in use here in the USA is called OPTICOM (spelling?) it is the little 1 or 2 sensors about 3in or 6cm sitting on the arm that the light heads are mounted on. Usualy these atre aon new (post 1994?) traffic signals or where the city has the money to replace them as they are using patented technoligy. You can see the emitter in the middle of firetruck/cop car light bars up close you can see the honeycomb that keeps the signal pointing forward only. There is a specific flash frequency although it seems the blinky your hi-beams works for me. I had to install these in the small fire dpt I worked for, while I was told they were tuned for the city we were in I think they are universal.
firemannn, Dec 26 2002

       Actually in the USA they use metal detector like sensors. Look on the streets right before an intersection there are either circle, square, rectangle, or diamond sawcuts in the road wich contain the wires of the detector. So lets say you are a motorcyclist with and aluminum frame? The light will not turn green for you until a car rolls up behind you. There are now Greenlight Triggers(look on ebay-CHEAP!) out for cyclists so the sensors will recognize a motorcycle. Anyway i think someone should send me a link about a real signal changer not some fake crud that MIGHT work. email me @ memememe0069@yahoo.com for feedback.
gixxer750g, Dec 08 2003

       Where I live, blinking your lights to make the lights change would have just the opposite effect of what you desired. When actived by a strobe light, all lights change to red. This allows the emergency vehicles to transit the intersections with no traffic moving in any direction.
Klaatu, Dec 09 2003


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