2007-06-15 11:46:13 · 10 answers · asked by Anonymous in Cars & Transportation ➔ Safety
NO
Photo cell
When dark go on
Tunderstorm or darkness they light
Ex raildoad worker
2007-06-15 14:48:05 · answer #1 · answered by Michael M 7 · 0⤊ 0⤋
Lights are on a preset timer. However, they also have a sensor imbedded in the roadway wich is triggered when it senses large metal objects over it. Ever see a motorcycle sitting at a light that wont change? that's cuz they don't have enough metal to trigger some sensors.
2007-06-15 19:07:56 · answer #2 · answered by randy 7 · 0⤊ 0⤋
They are controlled by either a timer or a magnetic strip that sits close to the surface of the pavement at the light.
2007-06-15 18:50:11 · answer #3 · answered by Yes I am here!! 5 · 0⤊ 0⤋
If you're asking about electroliers that illuminate the roadway, they are controlled by photocells that turn them on or off depending on ambient lighting conditions.
If about traffic signals, they are controlled by detectors - pavement loops or cameras for vehicles, and pushbuttons for pedestrians or equestrians - that set the timing according to vehicular or pedestrian demand.
2007-06-16 03:47:33 · answer #4 · answered by sweetwater 7 · 0⤊ 0⤋
I think its some math equations that control when it changes during different times of the day.
2007-06-15 18:48:58 · answer #5 · answered by Moth 3 · 0⤊ 0⤋
i honestly think they are controlled by time because have u ever noticed that when the time changes the lights will come on before it is actually dark????
2007-06-15 18:53:46 · answer #6 · answered by Ms. Tee 4 · 0⤊ 0⤋
lights r on a preset timer
2007-06-16 02:51:19 · answer #7 · answered by manchester 3 · 0⤊ 0⤋
most are either timed or set by senors in the intersection, if there's another changing method i don't know about it.
2007-06-15 18:56:00 · answer #8 · answered by Anonymous · 0⤊ 0⤋
no by light they are light sensored
2007-06-15 18:48:57 · answer #9 · answered by corykaresa 3 · 0⤊ 0⤋
No!
2007-06-18 19:48:04 · answer #10 · answered by katty 5 · 0⤊ 0⤋