Motorcycles and Traffic Lights

madurobob

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madurobob
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Will a powerful magnet help trigger inductive-loop traffic signals?

I am an avid motorcyclist. And, as anyone who is, I have a hatred of most traffic signals. Most signals where I live have sensors that detect vehicle activity and trigger lights accordingly. Like anyone who has spent much time riding a motorcycle, I've run my share of red lights after realizing the sensor just didn't recognize my presence.

I know most sensors are not triggered by weight per se, its more of a mass issue. They are triggered by changes caused by a large (enough) metal thing disrupting the magnetic field of the inductive loop. You can often see these inductive loops cut into the surface of the road just before a traffic signal.

I've heard that several states have passed laws making it legal to run a red light if the signal does not change and there is no traffic. This seems reasonable to me, but also a little dangerous. I started wondering last night if there might be a better solution.

I have a few large (1"X1"X2") rare earth magnets that are wicked strong. So strong my wife cannot pull them apart when they are touching. I can pull them apart, but its dangerous - I've lost chunks of skin when one slipped from one hand and slammed into the other magnet, pinching my skin between them.

I think you can see where this is going. If I took one of these magnets and stuck it on the bottom of the frame of one of my motorcycles would that have an effect on the inductive-loop driven traffic signals? Would the signal now recognize my motorcycle as a vehicle and change the light for me?
 
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madurobob said:
I am an avid motorcyclist. And, as anyone who is, I have a hatred of most traffic signals. Most signals where I live have sensors that detect vehicle activity and trigger lights accordingly. Like anyone who has spent much time riding a motorcycle, I've run my share of red lights after realizing the sensor just didn't recognize my presence.
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Are you saying that you approach a red light and anticipate it turning green and so you just go straight through and sometimes it turns out the light doesn't change to green and thus you've run a red light? If so that sounds pretty crazy to me. If you come up to a light and it's red, then stop. If you're stopped at it for awhile and it's not changing and you think something might be wrong with it and if no other vehicles are coming then go ahead and ease through the light. But coming up on a red light and not stopping at all? Not so good.
 
Number Six said:
Are you saying that you approach a red light and anticipate it turning green and so you just go straight through and sometimes it turns out the light doesn't change to green and thus you've run a red light? If so that sounds pretty crazy to me. If you come up to a light and it's red, then stop. If you're stopped at it for awhile and it's not changing and you think something might be wrong with it and if no other vehicles are coming then go ahead and ease through the light. But coming up on a red light and not stopping at all? Not so good.
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He's saying that he stops and waits a while and realizes he's not been able to trigger it, then goes.
 
madurobob said:
Great info there - thanks!

I'm still curious, though, about the debate that article mentions about whether a magnet will work or not.
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Funny, you talk about that! When I used to ride with my X-husband, one of the lights close to home was on a corner with a gas station, and if the light was red, when we came up to it, we would go through the parking lot, and get the green from the other direction!
 
IMST said:
He's saying that he stops and waits a while and realizes he's not been able to trigger it, then goes.
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:D Yes. I'm not just blasting through red lights at speed.


moebob said:
Funny, you talk about that! When I used to ride with my X-husband, one of the lights close to home was on a corner with a gas station, and if the light was red, when we came up to it, we would go through the parking lot, and get the green from the other direction!
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I once watched a motorcyclist sit at a red light for a while, then turn right on red, make a u-turn then turn right again. I guess the u-turn is legal so technically he did nothing wrong, but it sure looked odd me (the one who runs lights instead).

Anyway, I plan to test the magnet idea, but I was curious about the science behind it.
 
moebob said:
Funny, you talk about that! When I used to ride with my X-husband, one of the lights close to home was on a corner with a gas station, and if the light was red, when we came up to it, we would go through the parking lot, and get the green from the other direction!
Click to expand...

On more than one occasion I've had my passenger get off and go hit the crosswalk signal to get the light change. :)

At stubborn switches I got used to pulling up as close as I can and hitting the crosswalk signal myself.
 
Look for the position of the loop in the pavement. Ride over and stop -on- the line in the pavement where the loop is.
I get the gate at the front here to open with my 10-speeds by riding slowly over the actual loop.
 
More and more signals around here are using cameras instead of inductive loops. I have trouble with them and my motorcycle too. :P

I don't understand why it's so hard to get a confirmed answer on whether or not magnets work.

 
patchbunny said:
More and more signals around here are using cameras instead of inductive loops. I have trouble with them and my motorcycle too. :P

I don't understand why it's so hard to get a confirmed answer on whether or not magnets work.

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*********** magnets...how do they work?

I always pulled to the right a bit when coming to a stop light. Maybe I'm just used to heavier bikes, but I never had an issue. There are a whole lot of urban legends surrounding this phenomena, I've heard just about everything from magnets to starting the bike over the plates.

Here's a few pointers: http://www.wikihow.com/Trigger-Green-Traffic-Lights
 
One light where I worked used cameras. I guess in infrared. They worked fine until one day I left my truck overnight, then went to make a delivery first thing in the morning. I had to sit there until the truck warmed up enough to make infra reds enough to trigger the computer.
 
Several years ago, one of the magazines, probably Cycle World or Motorcyclist, tested the "stop light magnet" that is/was advertised. It didn't work.

The real problem is the distance between the metallic mass (the bike frame) and the sensing loop. At that distance, introducing a magnet (of its size) has little, if any effect. (Inverse square law.)

I try to stop over the side of the loop, to cover as much of it as possible. I've had some luck with stubborn signals by lowering my kickstand onto part of the loop.
 
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Pantaz said:
Several years ago, one of the magazines, probably Cycle World or Motorcyclist, tested the "stop light magnet" that is/was advertised. It didn't work.
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So, my idea is not unique nor new... and doesn't work. Oh well.

Pantaz said:
I try to stop over the side of the loop, to cover as much of it as possible. I've had some luck with stubborn signals by lowering my kickstand onto part of the loop.
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The link to the wikihow posted a couple of times here gives that and a few other good ideas. It looks like I can find a way to trigger greens without a magnet.
 
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