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Discussion Starter #1
i've noticed that my jeep (2013 JKU with a 2.5 lift and 35" tires) has trouble triggering stop lights. there are some lights that simply will not trigger unless another vehicle pulls up behind me. i've tried pulling up far to the point where i am almost in the crosswalk. i've tried staying back. i've tried far left, far right and dead center of the lane. i've tried rolling back and forth in the area where the motion sensors were installed into the pavement. my wife's minivan will trigger these same lights instantly, before she even comes to a complete stop. whereas i have had to resort to getting out of the jeep and pushing the walk button to get the light to turn.

there is even one intersection by my house that, when i pull up, the cross traffic will get a yellow light, then a red light, then immediately turn green again without my light ever turning green! again, this light always works fine with my wife's minivan.

i assume this has something to do with the bulk of the jeep being higher off the ground than the average vehicle, combined with a sensor that isn't very sensitive. anyone else have this problem and any tips to get the lights to trigger short of running out and hitting the walk button?
 

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Research, bro!
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I get this a lot of the time too. I'd also be interested in knowing the legality of safely running the red light. As in no one is remotely near me when doing so.
 

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Random Dude
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My Jeep is pretty low over its 35s with a big-ass steel skid underneath, but on rare occasions I also have that happen.
My theory is: if I've sat through at least 1 or 2 cycles of the light, and I run it safely, no reasonable cop would balk at my 'splainin'.

BUT WAIT - YOU CAN FIX IT! :bounce: :
Some folks install a large-ish neodymium magnet on the bottom of their front diff (or bicycle, scooter, motorcycle, etc.) to trigger the inductive loop sensors.
 

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JKO Dickhead
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My Jeep is pretty low over its 35s with a big-ass steel skid underneath, but on rare occasions I also have that happen.
My theory is: if I've sat through at least 1 or 2 cycles of the light, and I run it safely, no reasonable cop would balk at my 'splainin'.

BUT WAIT - YOU CAN FIX IT! :bounce: :
Some folks install a large-ish neodymium magnet on the bottom of their front diff (or bicycle, scooter, motorcycle, etc.) to trigger the inductive loop sensors.

^ This - Neodymium magnet - doesn't not even need to be a big one and they sell them specifically for this reason.
 

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Most states have a law that states that if a signal is not working or malfunctioning, you are required to treat it as a four-way stop. If the sensor is not working, that's a malfunction. Stop and go. YMMV. IANAL, and all that....
 

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Comfortably Numb
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Actually the sensors are triggered by weight
So you need to add weight. The easiest thing
To fix this is for you to gain just little
More weight and the best way to do that
Is to quit pooping so no poppie for boopie. :thefinger:
 

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Magnet.

Use this trick on my motorcycle as it has the same problem. I have heard of laws specifically for bikes where you can legally run the light after a 5 min wait. (varies by state), but I've never heard of it applying to vehicles.

If you are a cheapskate and have an old hard drive laying around, you can open it up and you should find a neodymium magnet inside. Usually small and banana shaped. Works for the bike.
 

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JKO Dickhead
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Actually the sensors are triggered by weight
So you need to add weight. The easiest thing
To fix this is for you to gain just little
More weight and the best way to do that
Is to quit pooping so no poppie for boopie. :thefinger:
Not true.... how does my 25 pound road bike trigger the lights ?

the neodyne magnets are a huge thing in the cycling community
 

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Magnet.

Use this trick on my motorcycle as it has the same problem. I have heard of laws specifically for bikes where you can legally run the light after a 5 min wait. (varies by state), but I've never heard of it applying to vehicles.

If you are a cheapskate and have an old hard drive laying around, you can open it up and you should find a neodymium magnet inside. Usually small and banana shaped. Works for the bike.
^^This.

The vast majority of stoplights now use inductive loops in the pavement to detect the presence of something metallic inside the loop.

Motorcycles often don't contain enough metal for the inductive loop to detect accurately, so many will add neodymium magnets. Oklahoma has enacted a law to allow (only) motorcycles to proceed through a red light if they have stopped and the light hasn't changed because, well, it doesn't know they're there.

With your Jeep being lifted, it's likely you don't have enough metal close enough to the pavement for the inductive loop to detect its presence.

Sticking a magnet to your front diff should solve the problem.
 

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Some sensors are weight, others are inductive loop...

Lifted jeeps just need either an air ride suspension or some sort of go-go-gadget bellypan to trigger the magnetic sensor...

I think the "light didn't work" argument will fail as soon as they prove it was your vehicle mods that caused the anomaly, not a defect in their equipment.
 

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I believe its triggered by metal. We might be a little to high to catch the sensors. If you look on the street you can sometimes see the outlines in the asphalt were the sensors are.
 

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Comfortably Numb
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Not true.... how does my 25 pound road bike trigger the lights ?

the neodyne magnets are a huge thing in the cycling community
Shame on you. You of all people should know not to take me seriously.....all the time. I have no clue as to what activates the lights.
 

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JKO Dickhead
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Shame on you. You of all people should know not to take me seriously.....all the time. I have no clue as to what activates the lights.
I actually thought that after I typed it.... but was multitasking. Damn I'm usually pretty sharp on those !
 

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I have a light that I hit every morning on my way home from work. I have pull up stop put it in reverse back up and repeat a few times. It is a busy bad ass intersection and unfortunately I am the only one ever headed in my direction at 0600 hours. Not safe to run it either as cross traffic is heavy going 5mph and 5 lanes of traffic. Usually a couple back and forths trigger it.
 

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BUT WAIT - YOU CAN FIX IT! :bounce: :
Some folks install a large-ish neodymium magnet on the bottom of their front diff (or bicycle, scooter, motorcycle, etc.) to trigger the inductive loop sensors.
Thanks for this, Ex. There is this one diabolical light by my house that gets me all of the time. Sometimes I have even hopped out and hit the pedestrian crossing button.
 

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Discussion Starter #16
how large of a neo magnet would i need? my kids and i race slot cars. they usually come with magnets but we race without magnets so i have a buttload of tiny magnets (like 8mm wide, 3mm tall wafers). would sticking 10 of these on my diff work, or do i need one big magnet?
 

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So I had this old (ESDI?) hard drive laying around out of an old Octel voice mail system and it just happened to have the most perfect magnets!

There were two inside and they did not even need to be glued in. I just tapped them out with a long punch and hammer.

They are perfectly shaped to fit right to the axle tube in a protected spot above the LCAs.

If just one works for me, you can come by and grab the other.





 

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Looks like it may be legal to run the stop light in some states.

If this article that I found on a Vespa board is correct, then here in California we can just call the city and ask them to fix it.

The article is also suggesting that magnets do not work either because the loops do not actually detect a magnetic field - they detect metal.

So far my magnet test has been unsuccessful, which would corroborate the above.

http://modernvespa.com/forum/wiki-trafficsignals
 

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Looks like it may be legal to run the stop light in some states.

If this article that I found on a Vespa board is correct, then here in California we can just call the city and ask them to fix it.

The article is also suggesting that magnets do not work either because the loops do not actually detect a magnetic field - they detect metal.

So far my magnet test has been unsuccessful, which would corroborate the above.

http://modernvespa.com/forum/wiki-trafficsignals
But like mentioned before it only applies to 2 wheeled vehicles for running the light.

The theory I was told is the magnet disrupts the magnetic field of the sensor which is exactly what a large chunk of metal does.

It seems to work for me, but I don't ride much in the city anymore either.
 
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