Flashing highbeam to change red lights?
11-17-2002, 09:50 PM
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Flashing highbeam to change red lights?
Maybe I'm the last person in the world to know this or maybe this is just a joke.
I know traffic lights have sensors to pick up the strobe from fire trucks and ambulances, but I thought car's headlights couldn't activate the sensor because they can't flash rapidly enough.
My friend's girlfriend says that late at night, with almost no traffic on the road, she can get red lights to change by flashing her highbeams (she's got a CRX). On a few annoying intersections (where you usually have to sit for a minute or so for no reason at all), they tested this theory late at night and reported that within five seconds the light changed. I'm thinking it could be mere coincidence.
Anyone know?
-Dave
I know traffic lights have sensors to pick up the strobe from fire trucks and ambulances, but I thought car's headlights couldn't activate the sensor because they can't flash rapidly enough.
My friend's girlfriend says that late at night, with almost no traffic on the road, she can get red lights to change by flashing her highbeams (she's got a CRX). On a few annoying intersections (where you usually have to sit for a minute or so for no reason at all), they tested this theory late at night and reported that within five seconds the light changed. I'm thinking it could be mere coincidence.
Anyone know?
-Dave
11-17-2002, 09:55 PM
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Used to work for me when I was in SD almost all the time...
tried a few times up here in the bay area to no avail...
then again, most of the time the ground sensors do a good job when it's late out and no one is around -- the lights change pretty quickly...
then again, most of the time the ground sensors do a good job when it's late out and no one is around -- the lights change pretty quickly...
11-18-2002, 01:30 AM
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If you look at the street prior to the intersection, you'll see lines...(m)
cut into the asphalt in a rectangular type shape. Those are electrical sensors tied to the light signal. There is a specific amount of current running in there and when your car goes over it, because your car is metal and will draw some of the current, the signal detects a change in the current it is receiving and therefore changes lights. Even a simple bicycle can make the signal change. The best way to make the signal change is to place your car over 2 of the sensors.
11-18-2002, 06:13 AM
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This is true, but he's talking about the light sensors. They do exist, but many cars can't (m)
activate them because their lights aren't bright enough that high up. Police vehicles have brights that are angled up slightly more than regular consumer vehicles, and therefore emit more light up higher. I've noticed i can usually do this trick when the road leading up to the intersection is on an incline, pointing up toward the light more.
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11-18-2002, 08:25 AM
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Here in chicago a special infrared transmitter is used by emerg vehices (not from strobe lights)
And the transmitters are muy expensive from what I understand, to deter civilians from getting them.
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