It depends on what signal light changer you're talking about. Most cities use an inductive loop in the ground that senses when a mass of ferrous metal is near it to change the light for waiting traffic. You can usually recognize these by the loops or squares that you see cut in the pavement near the intersection where the small wires are buried. If you are riding a motorcycle and not changing the lights, you can buy a block of metal that you bolt to the underside to help trip the sensor. More and more cities are now also using video cameras that detect traffic, and there's not much to do. Finally, if you're talking about how buses and emergency vehicles get the lights to change more quickly for them, or out of sequence, the system I know of is made by 3M- Opticon. They use a strobe light to change the signals. One strobe speed (10 Hz) is for public transit, another (14 hz) for emergency vehicles. You can find the specs online and them make a strobe from Radio Shack, or buy one for a bit more from Gall's online catalog. May be illegal in some places.
flashing lights at the beam on the top of them works...........thats what the police do.............
I am not sure those are legal to sell. I know in some places they are illegal to use. You should check before trying to get one of these..
good luck with that just do a search for M.I.R.T. and youll find all ya need to know
