a motorcyclist's blog

Stuck at a Traffic Light, Try This

traffic-lightI’m sure this has happened to you. You’re out for a ride on a hot Sunday afternoon. The back-roads offered up plenty of fantastic twisty asphalt for your pleasure and you’re beat. You’re now plodding down the secondary roads and you come to a quiet intersection with a traffic light. As you sit there feeling the heat from your engine flow up around your legs, your mind starts mulling over the idea of just running the light.

I have found a very reliable method for triggering the sensors on traffic lights so that running through the red isn’t necessary. If you can spot the inductive loop sensor on the ground (a thin rubber strip making a box on the street) try to position your bike so that you can put your kickstand down right on the strip. Putting a steel kickstand down right on top of the inductive loop sensor is often enough to “trip” it to let the lights know you are there.

Want to know why this works? Read on…

So why does this happen to us motorcyclists so frequently? Often it is the fact that motorcycles just simply don’t contain enough metal to trigger the inductive loop sensors in the ground at many traffic lights.

Though the average motorcycle does have quite a bit of metal mass, it really is quite small compared to the mass and area covered by your average car. Also, some motorcycles contain more exotic metals like titanium, magnesium, and other “ium’s” that are not as conducive to triggering these sensors. Let’s look at why.

Many traffic signal control boxes use inductive loop senors embedded in the asphalt at intersections to determine when a vehicle is sitting there. These sensors are made up of large loops of wire that are then covered with a rubber seal. They are usually visible on the ground and are about an inch wide and in the shape of a large box with angled corners.

sensor

Current is sent through the wire coils and a sensor monitors the inductance. When a large piece of metal (like a car) is placed in close proximity to the wire coils, the inductance increases and the traffic light system now knows a car is waiting at the traffic light. Even a large car doesn’t make a drastic change in inductance so something as small as a motorcycle may go unnoticed.

Using the technique of putting your kickstand down on the loop helps overcome the lack of mass by placing what is essentially a steel bar in nearly direct contact with the inductive loop. This close proximity is usually enough to trigger the sensor and you can move through the light legally.

I must point out that you should be very mindful when using this technique as it is easy to forget the stand is down and you will find your engine quits the moment you click into first gear with the sidestand down or worse you could ride off with the stand down if you have an older bike (ask me how I know).

If this article sounds familiar, it may be because you saw this on the since old Nashvilleriders website in the past. Recently I’ve started pulling up some of my articles from my old site to place here on Motorcycle Words. Why duplicate the effort, right?

3 Comments

  1. Gunner45

    My Yamaha has an aluminum kickstand. Tn lets you run red lights if safe.

    • Brandon

      I get that. This technique isn’t a panacea and there are plenty of intersections where one cannot see the sensors. Still If I can trip the light I’ll do it as it just makes it safer.

  2. "CJ"

    We used to go on the smaller general aviation taxi and runway to drag race late at night.
    To get past the security gate a tin plate stored in the bushes nesr the gate we placed across the exit loop just inside the gate. Fast forward decades later now having serious security not playing around like we used to do years ago.
    A bicycle layed over parallel above the wire trips some signals but it’s up to how sensitive the the loop signal is adjusted triggering or not your there.
    Several main intersections have been reset to pick up bicycles in ths “bicycle friendly” city I live in promoting bicycle useage. Also good to know the traffic light division supervisor as a personal friend also into vintage motorcycles.

    I recall years ago these light trippers were illegal but now see several on the market I posted above.
    A friend of mine has an infrared transmitter that will turn red lights green over a long block before the intersection. I bet this is a big no no by the Poo Lice if caught…..
    Has me thinking a vibrator unit sending pulsed 12 volts to an ignition coil, secondary wires with a fixed 1/4″ spark gap placed just above the roadway over the loop coil, will it trip it?
    Friend built a unit years ago when there was basic radar, he could dial up any reflected signal from zero to any speed like 250 mph by the twist of a knob marked 0-100 scale.
    Aimed at a intersection with a “trigger happy” radar cop with gun pointed at an old VW Beetle the return signal to the cop went from 0-78+ mph when the light turned green in under 100′, The cop did pull over the VW driver, funny as hell…..&o>…….

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