I recently asked our readers to write in regarding their personal experience with triggering the sensors at traffic lights, whether by means of some aftermarket products which claim to accomplish exactly that, or by using certain tricks which are alleged to help a motorcycle trigger the sensor. Here’s what some of them had to say (the rest of the responses will be included in Part Two):

• I put the sidestand down at lights to get A large bit of metal very close to the sensor.
• Save your money. In 20 years of riding, positioning your bike directly over the sensor wire(look for cuts in the pavement) has rarely failed. If, however, it fails, just go through when traffic is clear. Most states have a signal trip failure provision. If they don’t, a sympathetic officer should understand……….maybe.
• I have found that putting my kickstand down at the offending lights usually works, but there is one stubborn one near my house in the valley that does not even take to that. I always run the offending red light after looking both ways if it does not trip after a full cycle. The rumor is that this is legal and THAT would be interesting to find out.
• As a 4th-year Electrical Engineering student and simply as someone with some common sense, I can tell you without a shadow of a doubt that rotating metal at a high rotational velocity to generate or increase a magnetic field is complete and utter crap.
• i know this is crazy, but i just throw the kickstand down tap it on the ground once or twice then kick it back up. i always make sure im in neutral and that there’s no traffic around….
• Being both a motorcyclist and bicyclist, I have found that the sensor can be tripped sometimes by something as light as an 16-lb CARBON FIBER bike, as long as the rims are metallic (aluminum, in most cases). I have fairly good luck by riding along the wire in the ground, and on the motorcycle or bicycle, stopping with the front wheel at the left or right “front corner” of the loop wire. On my bicycle, the rim is a 400-gram hoop of aluminum, but it is only 7/8 of an inch or so off the ground, putting that small amount of metal fairly close to the wire (unless the little crevice the wire is in was cut too deep). On my RT (120/70 section tire) the rim (though much more massive) is about 3-1/4″ from the ground but the heavier rim and disc brake rotors give a better chance of activating it. My 650 with the 90mm front knobby on a lighter rim sometimes will not trigger a light that I regularly get to trip with my bicycle… Annoying, but I have found that if I got pulled over after safely making a left when the traffic was clear, I’ve been able to talk my way out of it. One time involved the mention of filing a suit against the county and Caltrans that all signals be calibrated to trip when any legally registered vehicle passed over it… While he and I both knew that probably wouldn’t go anywhere, it would be enough of a pain in the A$$ and cost enough to deal with that he dropped the issue.
  
  Sure like to know if there is anything out there that would work for the thumper!

• I’ve heard of other two solutions:
  A) pull down your centerstand (providing your bike have one) with your left foot so that it slighly increases the amount of “metal” near the sensor.
  B) Find out who’s in charge charge in your city/district, and have the sensitivity of the sensors for that specific traffic light increased.

• Hey Alex,
  I’m a frequent reader of Motorcycledaily.com! I just read your rant on traffic lights. I too run into the traffic light problem. I’m working on research project at UCSD titled, Vision Based Traffic Light Triggering for Motorbikes. Basically I’m researching ways in which video footage can be used to detect motorbikes rather than an inductive loop. I’m still in the early stages of my project but I have a lot of hope for it. One of the herustics I’m trying to take advantage of is that all motorbikes are required to have their headlights on. Because of this, image processing can be done to find such an object out of a background. Please check back in a few weeks!
  My progress can be traced on http://motorbikevision.blogspot.com/

• Regarding the inductance loops for light triggers, most of the tips as mentioned in the article don’t work. The wires can’t sense motor rpm or charging system output. They do sense the magnetic material in a vehicle to trigger the signal. (stangely enough, ever notice how many loops are placed in the pedestrian crosswalk? Check it sometimes – it’s crazy how many are too far forward) Anyhoo, if you have a steel kickstand, place the kickstand down on one of the wires in the loop while you wait for the next light cycle. Works everytime.
• First off, let me say that I am a senior computer engineering undergrad with a focus on hardware studying at Texas A&M University. While I am not an electrical engineering major, electrical circuits play a large part in my course study. I had to bust out some old textbooks to get the gritty details, but I think (hope) I can make it an easily understood thought.
  
  Contrary to popular belief, traffic lights do not operate on pressure sensors nor are they magnetic. Only a conductive material is necessary for the inductive loop type. The link in the article that explains how an inductor works is operating on a very basic DC circuit. While it is true that an iron core in the inductor raises the inductance, in an A/C circuit this happens only at low frequencies, like 60 Hz for instance. Reading around some on the internet found that most inductance loops for traffic signals operate around 20-30 kHz, though they can range anywhere from 10-60 kHz. At these higher frequencies, though, any boost in inductance from an iron core is overpowered by the induced electrical eddy currents which serve to reduce the inductance of the coil. In the traffic signal application, a car, motorcycle, or bicycle can be substituted for the iron core. So in fact, while the linked article claims the inductor loop circuit is looking for an increase in inductance, it is actually a decrease.
  
  Inductive loop detectors operate by sensing disturbances in the electromagnetic field created by the coil of wire built into the pavement. When any material composed of conductive materials passes over the loop, the magnetic field created by the A/C signal running through the embedded coil actually produces a small electrical current through the material overhead which in turn creates its own small magnetic field in opposition to that of the embedded coil. Simply put, the opposing magnetic field of the material therefore decreases the effective inductance of the coil which is then detected by the circuit through the resulting change in resonant frequency. The signal control unit now knows there is a vehicle present.
  
  The key, though, is knowing where in that loop or the area bound by that loop is the coil’s magnetic field the strongest. Where it is the strongest is where one will have the best chance at affecting it.
  
  The usual inductive loop seen on the streets is a rectangle with its corners cut off. The magnetic field produced by this loop is most easily accessible on the long, straight cuts in the pavement running parallel to the direction of travel. As the A/C current runs through the wires, a magnetic field develops around the wires in a circular pattern. For example, if you placed a wire directly in the center of a length of 6″ pipe, the remaining volume in the pipe would be the magnetic field. The field lines would be running in a clockwise pattern around the entire length of the wire, assuming the current is traveling away from your vantage point. By placing the wheels of a motorcycle, or a bicycle for that matter, directly above the wires, the magnetic field lines running in that circular pattern around the length of the wire will then pass through the loop of the wheel. We call this the amount of flux through the wheel. The larger the number of field lines that pass through the wheel in turn creates a larger opposing magnetic field which, as stated earlier, will cause events to trigger the light. If the wheels not positioned directly above and in line with the embedded wire, the effect will not be as great as the flux is reduced. This is the reason why many bikes that come to a stop in the middle of the loop at a light have trouble tripping it as not many field lines are running through the wheels.
  
  Taping magnets to the bottom of your bike is going to have an effect on the inductive loop as it obviously creates its own magnetic field. The kicker here is, again, placement of the magnet (ie, bike) in the lane and how strong the magnet is. Turning your bike off and then back on will create a magnetic field for a small amount of time as the starter uses a coil. Running current through the coil will produce a magnetic field, but placement of the bike in the lane and if the short burst of current through the starter coil would be sufficient are issues with this idea of triggering the stoplight. I have never heard of people revving their bikes to trigger the light, but I guess I can see where they might think it has an effect. I doubt it truly does, though, as the alternators on bikes are quite small and they are pretty far, relatively speaking, from the embedded loop in the pavement to have much effect in my opinion. Besides, why create excess noise and irritate other drivers on the road when there are other perfectly good solutions to the problem.
  
  Whenever the cuts in the pavement are obvious, I always park my wheels directly over them and in line to have the greatest chance of triggering the light. I would have to say I have a success rate of at least 95%. It doesn’t cost anything to plan ahead when you are coming to a stop at the light, nor do I have to secure any extra weight to my bike in the form of a magnet.
  
  Lastly, thanks guys for a great website. I truly enjoy it and glad yall haven’t gone “subscription” mode only like some other ones.
  
  —
  
  I forgot to add, I ride a 2001 Aprilia Falco. My wheels are aluminum, my engine cases are all aluminum, and obviously so is my frame. Off the top of my head I can’t think of anything on my bike that is substantial in size made of a ferrous material.
  
  I just wanted to add that in case anybody was skeptical of the whole magnectic materials vs. non-magnetic materials for triggering the inductive loop at lights. As I said in my previous email, I have no issue at lights when I park the wheels appropriately over the embedded wires.

• Traffic lights (in the Bay Area) were a big problem with my little Beemer 650 single, which didn’t seem to have enough metal to trigger the sensors. Re: hard braking. I know that the sensors don’t detect weight, but sometimes I would brake hard over the sensors to try and get the mass of the bike a little closer to the sensor wire, in the (often vain) hope of tripping them. Anyway, the solution for me was a little magnetic device that attached to the bottom of the bike (I think I bought it from Aerostich). I didn’t do any scientific studies, but I didn’t seem to have any trouble at the lights any more. Love your site, read it every day. Thanks!
• Hello, I have been riding since 1966. Never had any problems with stop lights until they got high tec. . What works 95% of the time for my Honda VTX is “The Green Light trigger”. It’s not that high priced, and it works. You have to install correctly, and cushion it against the mid-lower-frame of the bike; I used some Heavy-Duty sheet rubber [black]. Cut the rubber not to excess; neatly. use [3] black zip-tys, and no body will ever know it is there, except BIG RED LITES! 🙂 . www.greenlightstuff.com
• Hey Alex
  
  I live in Denmark and I have the same problem every time a new loop is installed in the tarmac somewhere and I can tell you that there’s only one solution thgat really solves the problem. Give the local authorities in charge of the road and traffic lights a call (they problably have different names, depending on where you live) and tell them about your problem. If they are worthy of their pay, they’ll send a technician out to adjust the trigger level of the sensor. I know for a fact that they can be adjusted to be triggered by a bicycle – that’s all the metal needed if adjusted correctly.
  
  If no one calls them, they are gonna continue to install them with the way to high trigger level, because it won’t give them any false triggers – hence no complaints – that’s until you all strat to complain that they aren’t sensitive enough.

• I tried one of those magnetic traffic light triggers; it just attached to the underside of the bike with a couple of wire ties, but it didn’t trip the traffic lights as claimed. What usually works for me, is to stop my bike with my wheels resting on the wire buried in the pavement. This puts my engine (where all the steel is located) as close to the wire as possible. On stubborn traffic sensors, I shift into neutral and put my sidestand directly on the wire and that usually gets the job done. But don’t forget to pull up the sidestand before putting the bike in gear and causing it to stall. (blush)
  
  Motorcycle Daily has been my home page for years, keep up the great work.

• Alex:
  
  Nothing seems to work consistantly in my town (central British Columbia, Canada), so I have, on file, a letter to the Mayor, explaining the problem, and asking him to rectify the situation.
  
  Then, if I am pulled over for running a red light (after coming to a complete stop), I intend to use this evidence in my defence if I am cited.
  
  I cannot think of any other reasonable way to deal with the problem of “unsensing sensors”.

• Dear Alex,
  
  I live in England but I worked in the US for 9 years in the 90.s, Arizona then California. I came across this problem particularly in Arizona (no lane splitting etc) and one suggestion was to switch the headlight on and off. Again, a similar idea to revving the engine, a current surge causing a fluctuating magnetic field, triggering the sensor.
  
  Did it work? Well I think sometimes it did but you know what perceptions are like. It.s quite a simple thing to try you perhaps some of guys over there can give it a go.

  I just don.t have the problem over here, so many cars I.m never alone at the traffic lights;-).

• For the last 2 bikes I had this problem until I installed a couple of very strong magnets on the bottom of the bikes. The problem went away. I have several intersections that are on my main travel routes that employ the sensors. I would get stuck there until another vehicle came along, some times this could mean several cycles of the lights depending on the the time of day. I decided to try a magnet, and thought the more powerful the better. http://www.kjmagnetics.com/ has neodymium, I bought a pair, slipped them into a 3″ section of heat shrink tubing and zip tied them to the bottom of the frame(Yamaha V-Star), or on the center stand (Suzuki V-Strom). I can verify that these work, and I have had not problems with my bike.

  The ones I bought cost 2.60 each http://www.kjmagnetics.com/proddetail.asp?prod=BX084.

  Cheap effective solution.

• Hi Alex, thanks for posting this article–I don’t have any of the gadgets to trigger the sensors but I do wear steel toed boots, and I usually maneuver so I can put
  my foot right on the spots where the “lines” cross each other—I’m not for certain if it works but the lights do change when I do that—I try to get my toe right on the lines.

• How bout we give MythBusters a call!
• A motorcycle has not enough metal mass existing close enough to the pavement to disrupt the Magnetic field at most red-light. There is a sensitivity setting the traffic engineers can set to accommodate for this but a Call to the local city traffic and request would have to be made for each intersection that causes you loss of time.
  I have bought the strong Magnet, installed under my motorcycle without much success. Of course it is a dual sport so it sits very high off the pavement/ground.
  What DOES work is to pull up next the buried wires and put your kick stand down on top of the wire. This connects the entire metal mass of the motorcycle to the inductive Loop (magnetic field) and makes a fluctuation of the magnetic field causing the Hall effect transistor to switch and the Light will change to green.
  I have proved this time and again on motorcycles of all sizes, even a small scooter with a side stand.

• I was told that the corner or end of the loop is the best place to trip the sensor as it.s supposed to be the most sensitive location of the loop. So as you pull up to the light you want to be looking for the loop and position your bike just inside the box. Seems to always work for my Ducati and Buell.
• Regarding detecting traffic sensors with motorcycles:

  Why don’t you mention this as a potential test to Mythbusters?

  They could test the various methods, report back and all the non-motorcyclists could help take up our plight.

  OK, I’m naive… (but the Mythbusters suggestion was real.)

• Washington ST recently passed a law allowing motorcycles to pass on a red light if they have already sat thru a complete light cycle. It is better than the ticket they used to give, no matter how long you sat it was a red and you got a ticket.

  http://www.leg.wa.gov/pub/billinfo/2005-06/Pdf/Bill%20Reports/Senate/1466.SBR.pdf

• I’m not sure if this can apply where you are but here is my prefered method from down under. Being a simple fellow, my solution is both cheap (free) and effective (100% barring faults with the traffic lights. Once stopped, i turn off the bike, walk over to the lights, and press the pedestrian crossing button. If i’m not mistaken, this sometimes triggers lights faster than cars can (depending on the intersection), and has the added bonus of allowing me to have a quick stretch of my tired joints.
• You will undoubtedly be overwhelmed with responses to this irksome issue. The answer, for some readers, is really quite simple. As noted with an inductive loop, it’s both the mass and distance of the metal required to trigger the signal. Mass is the enemy of most cyclists, so enough said about that. Distance, however, can be modified for those with centerstands on their bikes. A centerstand is usually a fairly significant sized hunk of steel hanging off the underside of the bike, and most importantly it’s moveable. For someone with a centerstand, all they need to do is stop directly on one of the loop lines, gently reach back with a heel and lower the center stand until it touches the ground above the loop and hold it there. I went for three years without driving cars, and while my CBR was the quickest, the slower bikes with the centerstands always got me through town faster at night – because I could trigger all of the lights.
• It’s best to stop in the middle of the loop. Moving in and out of the loop can help. In Virginia, they’re going to IR sensors mounted near the lights. I have no problem running the light after one missed cycle (after checking carefully for the Man).
• I recently read about a method for triggering traffic lights that I have tried a few times: deploy the bike’s sidestand directly on the loop wire. (The first time I tried this I was reminded of my bike’s sidestand kill switch! Bike must be in neutral to keep engine running.) This method only worked once in the few times I’ve tried it. Urban myth? Maybe.
• Tripping the traffic sensor:

  1) Put the bike in neutral;
  2) Put the sidestand down;
  3) When you see the yellow light come on, put the sidestand up;
  4) Shift into first gear;
  5) When your signal turns green, go.

  Maybe they’re not all bozos in Washington.

• Here in Brevard County Florida, most of the traffic sensors are
  new enough, and utilize sensing devices that any vehicle on
  the road should trip it. I ride a GoldWing and a NightHawk
  750 and there are no sensors in Central Brevard County that
  have not sensed my bikes. Also, I have not seen any vehicle
  that would not trip the sensor.

  Strictly my opinion: based on what little I know about the
  sensors, they should be able to detect anything from a
  cement mixer to a bicycle if installed correctly and the
  sensing equipment in the controller box is advanced
  enough.

  Again my opinion: most of the sensors that don’t work
  well with bikes are probably older and need replacing.
  Also here in Florida we don’t pave our streets nearly as
  often as they do up north. On my periodic trips to
  Kansas I’ve noticed that they sometimes just pave right
  over the sensor loops and don’t reinstall the loop after
  repaving. Also, the winter weather, frozen water in the
  street and in the loop can’t be good for them.

• I.m not an expert on induction, but in addition to owning a motorcycle, I bicycle frequently in areas that use these loops.

  If you think a motorcycle lacks sufficient metal to trip these sensors, you should try doing so on a machine that weighs under 20 lbs total, a fraction of that being conductive metal.

  If you want a chance at tripping these sensors, pull up with your front and rear wheels directly on one the long sides of the loop. This will put your entire bike as close to the loop as possible. That usually works for me, even on a carbon-fiber bicycle. In fact, based on my experience, you don.t need to have any iron (well, more than trivial amounts) on your vehicle to make this work. I.ve done this on aluminum-framed and carbon-framed bicycles as well as steel ones. All had aluminum rims.

  It doesn.t always work, and sometimes I proceed thru the red after waiting at least a couple minutes. Most timing cycles are less than that, and if the light was going to change on its own, it would have. At that point I treat the intersection like one with a malfunctioning light. Since crossing traffic has green, I proceed only when it.s safe.

• Alex, this doesn.t speak to the devices you asked about, but instead Tennessee has offered a better solution. Some time in 2005 (maybe early 2006) a law was passed that allows us to .run. redlights that don.t respond, as most don.t. You of course have to sit a reasonable time, watch traffic and proceed when safe, but at least you aren.t stuck there waiting for a car. Presumably you could get in an argument over the length of time you sat, but for lights you generally hit first thing Sunday morning, it.s really been a nice law.
• Hey, you missed one idea/solution, that seems to work for me [and others] – position your bike over one of the lines in the road that runs in the same direction you are traveling, deploy the sidestand down, rest the bike for a moment right on top of this wire/line. Since the vast majority of side stands are made from good ole fashioned STEEL, to resist bending and breaking from the weight of the motorcycle, this is usually enough to trigger “The Effect”… the idea is not to place any weight on the wire, but to get that hunk of Steel as close to the Loop as possible , to interupt the Halo effect…….. Remember to have the bike in Neutral , or the bike will Kill the engine when lowering the sidestand while in Gear…
• I’ve read your recent article on Motorcycle daily and I havea simple cost free solution to this common problem. Rather than bore you with scientific conjectures and equations, I’ll get staright to the point. If you look at the etchings in the ground for most of the traffic light sensors, you will notice two distinct loops within one road lane. (These are the inductance loops that you read about.) All you have to do to induce inductance accross these loops is provide a magnetic source across both loops simultaneously. To achieve this as a single ridier it simply means angling your bike across the centerline of the etchings in the ground. I have been riding for almost 2 years now and this works for me 90% of the time. If you want to set off these sensors while riding with two or more, you simply make sure your riding partner is positioned as close to the centerline (or prefferably in the center of 1 of the 2 loops) while you position yourself in the opposite loop.

  Scientifically speaking, I’m pretty sure that revving your engine doesn’t increase your magnetive properties largely (unless, you count your stator motor, which, for most bikes is located toward the shifter peg). The devices that you can buy in the magazines, usually work by supposedly increasing the size of the magnetic field present under your motorcycle, and given my method, probably arent worth the cost. There are times when my method proves ineffective. I attribute it to a faulty install, because I usually have problems at those same intersections in my car. And in those places in particular, I don’t mind running the light (provided the situation is 150% safe) in instances where no car is around.

  Oh, and if you are looking for more credentials. I am a recent graduate from the UNiversity of Central Florida’s Computer Engineering program. May not mean a whole lot to you :-).

• I have adopted a procedure that seem to work for me.

  As I approach an intersection with traffic actuated signals, I look for where the area is by seeing the marks cut into the pavement. I try and enter that area on one side, then ride diagonally across the sensor area. Since I’ve started this approach, most times I have not had any problems.

  Just an observation, no statistics to prove it.

• Lucky for us motorcyclists (and bicyclists, for that matter), the trend these days is to utilize camera detectors on top of signal mast arms to detect objects approaching and objects are at the stop bar. So, hopefully the inductive loops will eventually be phased out. Some towns/states are slow to switch though, as it’s expensive.

  The loops are supposed to be calibrated properly to detect cycles, but sometimes they are not. One thing that works at most signals in my area is to look for the sawcuts where the loops were put in, and drop your kickstand down onto it. Oftentimes, that extra proximity to the wire is enough.

  Also: There are periods in a timing cycle when loops are “turned off” (actually ignored) by the controller. Most commonly, the loops are ignored just before the signal enters a yellow phase. So if you arrive just before yellow and you are the only one in the left turn lane, a fully or semi-actuated controller may skip giving you the left arrow. They can also be ignored during some initial periods of opposing green. So when you put the kickstand on the loop is also important.

  One more thing: Don’t bother revving the engine or turning it off and on.

  Thanks for your site. It’s my home page.

• From a technical standpoint, I can’t help you. It’s possible probable there are different design elements that you’ll have to get from the manufacturers. You might also inquire from Design News magazine. They typically investigate engineering issues. I don’t know the circuit but don’t mind sharing my personal speculation. An inductive loop probably detects the vehicle’s mass by it’s effect on the resonant frequency of the loop. That said, I have installed driveway vehicle detectors that are sensitive enough to register the metal on a person (change, belt buckles, etc?) Therefore, the detectors may be adjustable in sensitivity. Again, I don’t know. What I think it boils down to is a bureaucratic/legal issue. If the local DOT can adjust the sensitivity, do they have standards in place that have them intentionally high to avoid false trips? When they appear to be slovenly, consider the enormity of the task they have to deal with. How many traffic lights are there? How do we get them to change? You can approach the bureaucracy. OK, good luck – how do you effectively do this? Individually? Concerned citizens groups? Motorcycle helmet groups have had some luck, for better or worse, changing the laws, but never the bureaucracy. That leaves the Law. I have a particular traffic light in Wake Forest, NC that does not register in one lane. Even my car. You have to be in the other of two turning lanes to get a left turn light. I have, on a couple of occasions sat at the light and called the local Police and asked what to do. Their advice is practical – to wait until it is safe and run the light. Have you ever noticed that dangerous situations (intersections, etc.) get changed after a few accidents and maybe, God forbid, deaths? My final suggestion is to get ahead of the curve. Engage you local law enforcement. Get them on your side (quite a few ride motorcycles on the off hours too). If the interim, or maybe final solution for a given light is to run it, at least when somebody’s mother calls to complain the Police are aware of it and can explain to other concerned citizens.
• Short of buying special devices to increase the likelihood of being detected by inductance loops, I would like to offer two pieces of advice for motorcyclists that are having problems being detected at a signalized intersection.

  First, look on the pavement for evidence of the detector loop. If the detector loop was installed after the pavement, the rider will see evidence of the saw cuts used to install the detector loop. If you can see the saw cats, place your motorcycle directly over one of the saw cuts where the inductance field is strongest. With a TD-1C .quadra-pole. detector loop (see attachment), positioning your bike over the center saw cut will give you the best chance of being detected. With a TD-1A detector loop, position your bike over either of the side saw cuts, typically 3. to either side of the lane center. If you can.t see the saw cuts, assume a TD-1C quadra-pole loop and position your motorcycle over the center of the lane. (I understand that this is counter to the conventional wisdom that you should avoid the oily center of the lane. But I also think that this practice is why bikes are sometimes not detected.)

  Second, if you and your motorcycle have a problem being at a particular intersection. TELL SOMEBODY! The loop detector amplifiers are adjustable for sensitivity and can usually be adjusted to pick up your bike. (The sensitivity level is normally set fairly low so as not to accidentally pick up vehicles in the adjacent lane.) Call your City.s Public Works Department and ask to speak to Traffic Operations. Tell them the name of the intersection and on which approach (street name & direction) you.re having the problem. This is an easy fix and we.d be happy to do it, but you have to let us know there.s a problem.

  Call us. It.s what we get paid to do.

  Edward

  Traffic Signal Systems Supervisor

  Public Works – Traffic Eng & Ops

  City of Hampton, VA

• I’m not an electrical engineer, but I do work with magnetism quite a bit and understand the concept of the traffic light sensor. Basically it’s a “magnet” that “senses” a vehicle (usually a car) over it due to the change in current and polarity because of the steel contained in the car/SUV/truck is attracted to the current. I used to ride a ’94 Honda Magna that sat fairly low to the ground and most of the time the engine (and steel frame) would set off the sensor with a little bit of hard braking involved to make the front end squat. If that didn.t work I’d press/tap the Start button. The current jolt from the starter motor was always enough to trigger the sensor. When I traded in my Magna for an SV650, I knew I wasn.t going to be able to make the front end squat enough to get the motor close enough to trigger the sensor and the frame wouldn.t help either. So when I came to a stop light (particularly a left turn) I would just automatically tap the Start button. Worked like a charm every time.
• I have employed the practice of running my tires along the visual left-side edge of the patch in the pavement, coming to rest alongside. It has worked for me in most cases but not always. So if there’s a loop underneath I may be close to being on top of the left side of it. Coming to rest directly in the middle of the patch seems to net me the worst results.
• Depending on the intersection I just pull passed the sensor and urge the car up over the sensor to trigger the light. In the case of no one around and the light cycles passed me once, I then treat the light as a four way stop then just go whether its legal in Florida is not known to me but we all understand the frustration we deal with waiting at lights.
• I purchaced at a harley shop a magnet (about $15) and strapped it on the bottom of my 99 harley dyna in about 2 minutes (me, the non-mechanic). I can verify that it consistently worked at a lonely traffic light where I needed to make a left turn early in the morning. Previously, I would be forced to make a right on red and then find a place down the road and u-turn, or alternatively, force myself to turn left on red when it was safe. My ZRX is without one, so I utitlize the alternative methods on that bike. I think the best method is to communciate to law enforcement that turns on red in such situations are inevitable.
• Alex, I was wondering if you could also include in your research some info about whether you can legally get a ticket for running a stop light if it is not working. There is one light that I consistently run because I have sat there for long periods of time in the past. Now, if I get to the light on my bike and I can safely go, I run the light. Note that turning right on red at this light is not an option because that puts me onto a 4-lane highway headed the wrong direction. It won’t make any difference in my actions, but I am curious if a cop can make a ticket stick for running a light that “doesn’t work”. One of these days I may find out… 🙂
• One method I have employed to trip lights that seems to work to some extent, is to put the bike’s kickstand down on the line in the pavement where the sensor is, and then move the bike back and forth at bit. This something a friend taught me long ago and sometimes I think it works and at other times it doesn’t help.
• We teach the Canada Safety Council (roughly MSF equivalent) m/c course here in Ottawa. We also have a website that features a rotating ‘tip of the week’ feature. Here is one the tips – apparently not many people know about the ‘sensitive dots’. I know they work, but I also know that not all of the sensor loops in the world have them.
• The way I am able to make the trigger work on the problem lights is to lower the side stand directly over the wire loop. But most of the time if you center the bike over the loop, which here in the south is a rectangular .pad..just ride up to the light directly over one side or the other and it triggers. I ride a Suzuki DL-1000 V-Strom.
• I have had very good luck by just putting my front and back tires on top of the wire cuts in the road, nearest the light. Whether it is the big city(San Francisco) or small town(Tehachapi) I rarely get stuck at a light.By the way the motorcycles that I ride range from my ST1100/R1150R to my little bikes CB350/CL450. Just keep in mind this also works without the help of cars. I don’t do anything special, but sit at the light. Maybe I’m just lucky, but I’ll take it.
• I can only offer hope for the future. My company supplies components to the traffic control industry. One of those components is a video control cable which connects a video camera to the traffic light control mechanism. The camera replaces “loop cables” by sensing the presence and lane location of vehicles and sending that information to the control mechanism. Although the video system is a more expensive initial purchase it more than pays for itself through lower maintenance costs. No pavement to tear up and repave for servicing.
• I.ve been reading your site for a while now and have always enjoyed it. I thought this time I might be able to contribute something myself. I.ve been out of college for almost two years now with a B.S. in Electrical Engineering and riding most of my life, I currently ride an 06 Kawasaki ZX-6R. While motors and windings aren.t my specialty I know the basics behind inductance. I don.t know if the coil packs in a bike are strong enough to create an EM field strong enough to obstruct the current flow in the loops of wire in the ground, but you should try and stop your bike in the very center of the loop in the concrete. The metal in your bike will be most effective at the very center. I know this isn.t always good practice as I try to avoid driving in the very center especially at stop lights since this is where cars usually leave oil on the road, but it will allow the magnetic metals in today.s super sport bikes to be the most effective.
• Don’t know where I read it, but a technique I use that sometimes works is to push down the center stand against the pavement. If I don’t have a center stand, I’ll put the bike in neutral, deploy the side stand and lean over to make contact. The idea is to bring some metal as far into the magnetic field as I can get it.
• A buddy of mine recently took the beginner MSF class and told him they suggested putting the kick stand down right in the middle of the sensor square. He mentioned they talked about kick stands normally being metal and the metal being closer causing the light to trigger. I unfortunately have a left turn on my way to work with a sensor light, which does not get much traffic. The kick stand method has actually seemed to work for me most of the time.
• How about putting down the side stand on the wire? I read somewhere that this is supposed to do the job, although I have never tried it. Hope someone will confirm this.
• Some states, Arkansas for one, have passed laws allowing motorcycles to proceed on red after stopping and waiting long enough for safe passage. That is the perhaps the best answer in a motorcycle ignorant society.
• Wisconsin recently enacted another solution to inductive light sensors –

  A motorcycle at a light that does not change is legally allowed to procede through the red light after a set time (45 seconds) and when traffic conditions allow him to do so safely. I believe several other states have similar laws.

  Here is a link to an AMA and ABATE blurbs on the new WI law:

  http://www.amadirectlink.com/news/2006/WIlaw.asp

  http://www.abatewis.org/page.php?section=4&subsection=1&alert_id=75

• Hello sir. I have no triggering device on my bike, but I wanted to tell you what Idaho did to help us with this. As of July 2006, if a stop light cycles twice without giving a motorcycle a green light, you can proceed on red if the way is clear. Like a yield sign in a way. It is not perfect, but it is better than nothing. Would other states do this??
• I have had this problem a lot here in Mass. and what I end up doing is waiting for the cars coming the other way to pass me and then I head across the intersection, ready to tell the cop that the bike will not trip the light, which they know. Maybe steel toe shoes would trip the light.

  Sometimes I wait for someone to pull up behind me, which at busy intersections does not take long and is safer than running the light.

  Ride a Buell which has the muffler under the bike! 🙂

• Ya know, there is a third option available: political. If we motorcyclists make our presence known, we can work to find a solution. (Hey, wait a minute. Isn.t there already a group that.s supposed to be doing this? Why hasn.t the AMA addressed this problem?) Maybe it.s along the lines of California.s .lane splitting isn.t legal, but it isn.t illegal, either. system. Bikes that are first in line at a stoplight (if a car.s in front of you, it.ll trigger the light for you) get to proceed in a safe manner if they wait a certain amount of time. That length of time would be tied to the length of a light.s cycle. Although that might vary from light to light, so maybe a better way would be to say that after sitting through a complete light cycle you can go when it.s safe to do so. Any accident resulting from a motorcyclist proceeding through a red light would be automatically deemed the motorcyclist.s fault. And, penalties for not waiting long enough would be enough to discourage cheating.

  Now, this doesn.t do a biker any good if there are no breaks in oncoming traffic and his bike isn.t triggering the light. Really, we pay the same taxes car drivers do (gas, sales, licensing, etc.). If the folk who decided to use that money to purchase inadequate triggering systems can be held accountable, we (motorcycle riders) should make sure it happens. Letters to the editors of mainstream press outlets, bills in state legislatures, maybe a well-publicized day when bikers go through red lights at intersections with stupid lights, anything to raise awareness. Because, if bikers make up 10% of the motoring public, you can be sure that 90% of the motoring public is completely oblivious to the problem.

• I’ve had limited success on my Vmax triggering these rogue lights by, pulling up to the “loop” in such a way, that I can put my kick stand down, directly onto the loop.

  I know this does work for a couple of rogue lights in my area (Northern VA), other wise I would still be there, waiting for the light to change!

• Just read your article on stoplights/motorcycles.

  Yep, a problem UNTIL I bought one of those cheap magnets advertised in a rag. In fact I bought two. I ride a Road King Classic, so if a “big” bike was going to trip the lights every time, mine should have. Problem was it didn’t. So the purchase. The cost was less than $30 three years ago for the two. Bought them over the net and don’t remember what the brand name was. Installation was as simple as cleaning a spot (cleaning solution provided in the “kit”), pealing off the tape covering the “sticky” side of the magnet and pressing them on. I put ’em under the front part of the bike. They worked as advertised from the get go. Maybe cause I bought two, maybe that wasn’t necessary, who knows. But very satisfied with the result. Haven’t had to wait for a car/truck since.

  My guess is that one could do the same thing by just buying a good sized magnet and putting on yourself and save a few bucks. You might try that to see if it works for you as an “home brew” and give your readers an alternative.

  I’d say mine was a good “investment”.

• After having problems with numerous lights near my home I installed a .Green Light trigger. device on my Valkyrie Interstate. Installation took about 5 minutes. It seems to help at some of the lights that were problematic before, but it is not foolproof. For the money I.ll keep one on my bike to help.
• Great article. But you’ll probably wind up with a bunch of “urban myths.” 🙂

  I live in the Santa Clara, CA area – aka, Silicon Valley. The town of Santa Clara uses the inductive loops, generally a box about 4′ per side. What’s unique is that the sensor box has an image of a bicycle and an arrow painted dead center of the loop. In other words, “ride here to be detected.” They seem to work. Given a lot of bicycles now are made from aluminum, carbon fiber, and other non-ferrous materials, and the only steel is in the pedal crank, I’d have to say that riding in the middle is the way to go.

  Now this make sense if you think about it. The current flow through the loop creates a magnetic field around the wire. This field can be envisioned as a donut with the wire passing through the hole in the middle. The trick for traffic engineers is to tune the circuit so that the edges of the left and right donuts (magnetic fields) slightly overlap. This results in the best sensitivity.

  Riding directly over one wire, left or right, may not work because the field is strongest closest to the wire and may not be sufficiently disrupted to trigger the circuit.

  San Jose uses a double loop running the length of the lane – two rectangles about 8′ long. This is nice because it keeps you off the grease line, which is the main problem with Santa Clara’s setup, and gives you a better chance of being detected because the two wires are closer together.

  As for adding steel or magnets to the bottom of your bike, these can work because of the increased ferrous mass. But again, it all comes down to how sharp the traffic engineers are in tuning the circuit.

• I actually purchased a large magnetic traffic light trigger, and it did work on most traffic lights that had vexed me previously. There were two that were still obstinate and wouldn.t go. Then I discovered that putting your side stand down almost always works. Just put the side stand down and let the bike sit on it. Try it you.ll be surprised. I.ve got six bikes, and it works on the bikes without the magnet device as well.
• I have been an urban rider for about thirty-eight years now, mostly in the Albuquerque area. The advent of the “loop” signal controllers has been a big problem here. The city has taken the position that motorcycles are of no concern to it’s schemes of traffic management. The current may, Mary Chavez, is oblivious to our problems. His biggest concern is increasing fines for the new, and excessive, use of cameras at intersections and on radar guns.
  Some time ago, I was sitting at a light – sitting there a long time – when I saw a cop coming. I decided to make an issue of the situation, so I ran through the light. Of course, he stopped me down the road. After the usual preliminiaries (“License and registration, please, sir.”), we had a good conversation about the problem motorcycles have with the loop sensors. He declined to give me a ticket, and said he would report the light problem to his suspervisors. Amazingly, a short time after that, I noticed that the particular light where he stopped me was adjusted to accept the mass of my motorcycle. I do not have trouble at that light anymore. This proves that the sensitivity of the loops can be adjusted to accommodate a motorcycle.
  I suggest that more bikers should make an issue of the matter.

• All that has to be done is get the stupid traffic engineers to set the sensitivity higher, it’s just electronics after all. Unfortunately, there doesn’t appear to be any city governments that give a hoot about motorcycle accommodation. There is even a possibility that the nearly inevitable “wait and run the red light” by a motorcyclist may be considered a revenue enhancement tool for the local city government coffers.
• There is another alternative which we practice. Stop, wait and then go when safe whether or not the signal changes. The object is to proceed safely without being hindered by bad traffic engineering that failed to consider motorcycles.

  If stopped by an officer, state, “if I’m ticketed, I’ll bring a class action suit against your municipality and all others which discriminated against motorcyclists for this design”. Problem is, we haven’t been caught yet to try this out. But it may work in the face of a legal challenge.

• I’ve seen a post somewhere that putting the bike on its kickstand will trigger the sensor and give you a green light.
• Put the bike in neutral and put the kick stand down directly on the pad.

  Have had some success with this method, could also be that it simply leans the mass of the engine a little closer to the sensor.

  I have one light that if I come up to it on the right side of the pad it won.t trigger, but on the left side it does!

• Where I work (NASA Glenn Research Center), we have a group of bicycle riders that face the same problem (even worse for bicycles) and they had a web page describing a way to drive over certain parts of the inductor loop to trigger the traffic light.

  http://www.grc.nasa.gov/WWW/AdvisoryGroups/GO-BIKE/loops.html

  I.m hoping this is not an .internal. only website so I apologize if you cannot read this. Basically they say if you drive over the lines that you see in the road, the lines going parallel to your driving direction (most of the loops here in the greater Cleveland area are rectangular) you should be on the most sensitive portion of the loop and thus have the greatest chance of triggering the signal.

• I used to work at a traffic control device manufacturer. I emailed a guy there to see if he can explain how the loops work and what to do to combat the problem. If he has time and is up for it I.ll pass your email addy along.
• An other way of triggering light change is to get off your bike and press the pedestrian button.
• Can’t comment on the effectiveness of the gizmos being sold, but TN does offer motorcyclists a unique solution. In Tennessee, if the rider notes the sensor is not picking up the bike, he may treat the red light as a stop sign, and proceed when it is safe to do so. I use this all the time, and it cuts my commute time a bit not having to wait for a car to come up behind. Now, if they’d only allow lanesplitting like I used to do when I lived in San Diego…
• My old 93 Yamaha XJ600 Seca II always had a problem with traffic lights. The engine had an aluminum block so there was not enough iron on the bike to be and the bike would rarely trigger the traffic light sensor. I was able to rectify the problem with the use of a High-Energy Ceramic Magnet. I just attached the High-Energy Ceramic Magnet to the bikes frame under the engine. Installation took about 10 seconds and the magnet was only $1.99 from Radio Shack. The rectangular Radio Shack High-Energy Ceramic Magnets are not marketed for this application, but they are cheap and they have a strong enough magnetic field to be picked up by the inductive loop of the traffic light sensor. The High-Energy Ceramic Magnet was only held on to my bikes frame by it’s own magnetic force, and it did not fall off in over 20,000 miles of riding. It was a great $2 investment.
• I alway place my kickstand down right over the inlaid sensor and that usually
  works at most lights. Some of these lights cycle several times (over 5 times) without
  a turn on your lane of direction if it does not sense a vehical. In 110 degree heat dressed in leather this could be dangerous.

• It is my opinion that most of the aftermarket products sold to eliminate this problem most likely will not work.

  Usually, the problem with motorcycle detection is associated with either a failed detector loop in the roadway, or the sensitivity settings of the loop detector card (the sensor that measures and picks up the changes in the magnetic field which is located in the traffic signal controller cabinet) are not set correctly. Most public agencies try to have the loop detector cards sensitivity settings set to detect the presence of the majority of vehicle sizes when the detector card is initially set up. BUT, in my experience, unless a motorcycle is in the area when the setup of the detector cards in the controller cabinet is being done, the technicians usually just gauge their sensitivity settings on the available traffic which is running through the intersection when they are doing the setup.

  95% of the time, a motorcycle is not specifically used when setting the sensitivity of the detector cards. The techs just set it up for the traffic they have available at the time they are there (mostly cars & trucks) and then walk away, happy that they have .done their job.. Unfortunately they have not truly set up the detector to pick up the smaller vehicles, which should include motorcycles. Years ago in California, the Caltrans Specifications for set-up and commissioning of new traffic signals included the requirement that the installing contractor provide the .smallest legally operable vehicle. for use when setting up the detector cards. We (as an installing contractor) used to use a Honda CT 90 for this purpose as that was the smallest legal vehicle per the Vehicle Code at the time. We used to have to set the sensitivity to pick up the CT 90, but not have nuisance false detections from a bicycle or whatever else, as false detections make people mad due to getting stopped when there is nothing waiting on the cross street. I don.t believe that this requirement is still in effect, or it is simply not being enforced any more. This is the biggest reason that these traffic signals continue to be a problem for motorcyclists.

  Also, lack of maintenance contributes to this issue as the .in-road. detection systems degrade over time and need maintenance to properly pick up motorcycles when/if they are properly set-up

  Good news is that current technology is slowly replacing the old style .in-road. detectors. New technology detection systems now use microwave radar and video detection to replace the in-road detectors, but they are expensive and with budget constraints are not being used as often as we would like. Microwave and/or Video detection will pick up any size of motorcycle 100% of the time and do not have the maintenance problems of the old style detection loops.

• I am an electrical engineer and patent attorney and what you are asking about is a fairly basic electronics question.

  You are correct that most traffic signals are triggered by an inductive loop. An inductive loop is a very simple inductor and you described the operation well.

  The best way to perturb (that is the technical term for modifying or interfering with) the inductive field is to place something (an inductive mass) that affects the field within the field.

  A sufficiently large inductive mass such as steel, iron or nickel, but unfortunately much larger quantities of aluminum and magnesium, are one way to perturb the inductive field.

  Unfortunately motorcycles typically do not have sufficient quantities of inductive mass.

  Distance from the inductive field is also an issue. A inductive field intensity diminishes as a square of the distance from the source. For example if an inductive mass of 10 pounds of steel is required to sufficiently perturb the signals inductive field at 4 inches above the coil in the road then it would require 100 lbs of steel at 8 inches and 10,000 lbs of steel at 16 inches and so forth.

  Another way to perturb the field is to place something that produces an active inductive field of its own within the traffic signal sensor’s inductive field.

  One simple source of an inductive field is a large electrical current flow such as created when starting the engine. Every electrical current flow produces an inductive field around the wire with the current flowing through it. This is why some people have had positive results with starting their bike. This would probably work best on bikes with the starter located low like on many Harleys, but would not work very well on most sportbikes with the starter located higher.

  One way to improve the results of this method is to use a very long cable between the starter and battery and run the cable along the bottom of the engine and thereby generate an inductive field low on the bike. You could also increase the density of this field by wrapping the battery cable in a coil. You can even further increase the field by wrapping the battery cable around an iron pipe or a large bolt and the iron pipe or bolt acts as an inductive core and concentrates the inductive field.

  CAUTION: You must also be aware of three things though with this method: First, the inductive core must be secured to the battery cable core or the core could be propelled out of the battery cable coil like a missile (do a search on “rail gun” and you will get the idea). Second, the longer battery cable and the coiled battery cable will both reduce the current that gets to the starter and therefore make starting the bike more difficult. Third, the inductive filed created will likely erase any magnetic media (audio, video, floppy disk and even many hard drives) within the range of the inductive field.

  Revving the engine MIGHT also help because as the engine revs up, the electrical current generated by the alternator also increases (to a point) and the current flowing from the engine to the battery increases. Also some alternators increase their own inductive field as they generate more electrical current so again revving the engine might help.

  All of that is much too complex though because every magnet has its own magnetic field. A magnetic field and an inductive field are very similar and as a result a magnetic field acts as a much larger inductive mass than the magnet that generates the magnetic field actually is. For example: a 8 ounce magnet can generate a magnetic field sufficient to perturb the inductive field of the sensor like 10 or 20 pounds or more of iron.

  As a result, the simplest solution (and I use this on a couple of my bikes) is to attach a 1 pound magnet to a lower frame rail (or a centerstand) of the bike. The magnet artificially acts like having a 20 pound steel plate bolted to the bottom of the bike. I use a couple of hose clamps to secure the magnet to the bike. This is not always sufficient but it works most of the time.

• As a bicyclist, I have the same problem. I use the “cleat” on the bottom of my cycling shoes. The cleat that I’m using is either steel, or a piece of plastic with significant steel hardware attaching it to the bottom of the shoe. I pull up to the light, and drag my foot across the “loop” of the sensor, preferrable near an intersection of the wire or a corner. Works about 95% of the time! I’ve seen people embed a chunk of magnet into the heel of their shoe/boot, this is a great way to do it as well.
• Your research is correct, the traffic sensors work by sensing the change of inductance in a coil of wire. The change of inductance is proportional to the mass of metal and the distance from the coil. A large mass may be farther away, but a small mass must be closer to change the inductance enough to trip the sensor. The best a motorcyclist can do is to position their bike as close as possible to the coil and hope for the best. The coil will be in the rectangular cuts in the surface. I use this method and it work almost all the time.

  The only magnetic field generated by a spinning engine is from the alternator. This field is small and should not change significantly with rotation speed. Stopping and starting your engine may produce a transient magnetic field, but the field would be of such short duration that the electronics in the sensor would filter it out as noise.

  I have not tried this, but one urban legend that may work is to lower you side stand and place it directly over the coil. You all know the danger of this one!! Don’t forget to put it up before you move.

• Alex, I’ve tried the magnetic signal trigger device that’s sold in the Marketplace section of several major moto-magazines. No go. No discernable effect whatsoever. But after discussing this with other sport-touring riders, another approach was suggested. By placing the side-stand of my Honda ST1300 directly on top of the inductive coil in the pavement, the signal changed. I tried this several times at different intersections and every time it worked quite well. I ride with several law enforcement motor officers and they confirmed the side-stand technique is what they use. It’s free and it works!
• I would like to shed some light on this issue. Inductance sensors work by “inducing” a current flow thru a conductor by passing a moving magnetic field across it, or likewise by passing a moving conductor thru a magnetic field. Alternators, generators, transformers, and many other devices use this property of an expanding or moving magenetic field to “induce” a current thru a conductor. So the sensor device consists of at least a single loop, but usually more, of magnetic material and a conductive element embedded in the asphalt that will deliver a small, but measurable electric current within itself when a vehicle crosses the magnetic field produced by the loop. the loop connects to a sensor that will trigger the light timing mechanism for the signal light to change when this current is generated. Unfortunately, vehicles with a large amount of aluminum will not induce any current, and therefore not trigger the light timing sensor. I have used the aftermarket magnets available, mounted on the inside bottom on my fairing with pretty good success. Though where it’s mounted does not allow the magnet itself to stay strong as it is not in direct contact with any magnetic material. So effectiveness will degrade over time. But this is the best solution I have seen so far.
• I have employed the method involving shutting down the bike and starting it back up again with the bike positioned inside the induction loop for several years now, and it has ALWAYS worked for me. My belief/understanding is that it is the large magnetic field generated by the cranking of the starter motor that trips the sensor. Obviously if you have a motorcycle that only uses a kick-starter, this method will not work. Since I usually encounter these loops at traffic light controlled freeway on-ramps, to speed things along I will often hit the kill switch as I approach the sensor, coast into place, and then quickly restart the bike once I am over the sensor. The response by the sensors and the lights is almost instantaneous.
• The solution is really quite simple. Look around you, if the coast is clear, no cops, no approaching vehicles, proceed through the red light with caution. Been doing this for years, works for me
• When I was young and my only transportation was a 10-speed bicycle, I thought that the lights were triggered by weight. I didn.t bother trying to understand how I could activate the lights with my bike if I rolled up to the light so that my tires were directly over the groove. Sometimes, I would bounce my wheel slightly over the groove as I sat waiting for the light. It generally worked and the light would change. In retrospect, I realize it was the steel bicycle wheel being close enough to the wire loop to cause the sensor to trip.

  Since I still believed it was a weight sensor when I started riding motorcycles, I.d ride up to the middle of the .pad. and the lights would never change.

  I don.t remember who enlightened me, but I don.t have too much trouble triggering lights anymore. I ride up the groove, stop with my front tire contact patch at the corner of the loop, and if that doesn.t trigger the light, I wait until it is safe to proceed and then go on my merry way.

• One way I could usally get the sensor to trip was to lower the kickstand and put it on the grooved perimiter of the concrete-covered sensor loop. When that failed, having the kickstand in on the grove, turning off the bike and restarting it did the trick.

  But I got tired of both of those methods and now I just use the ‘traffic light trigger’ magnet on the center stand. It works great. So far I have not found a light that it won’t trigger.

• I had the same issue on the normal route I take home everyday. I called the local city traffic engineers and they can out and reset the sensitivity on the sensors I was complaining about and now they sense my bike with no problems. More then one way to skin the proverbial cat.

  Folks probably won’t get the same results in all cities.

• Down here in Oz, flicking the pass switch on the left switchblock seems to do the trick.
  I’m guessing that closing the electric circuit does the trick.

• My friend Sid reads your site and by coincidence, I had just e-mailed him this review I found.
  

  > I thought you two might be interested in this. It’s a $20 super magnet kit
  > that straps to the bottom of you bike and ensures that the induction loops
  > in turn lanes will “see” your motorcycle.
  >
  > http://www.carbibles.com/productreviews.html#signalsorcerer

  I have never used this, and I don’t know the reviewer.

• Good subject for some input.

  First, another homebrew method to consider: putting you kickstand down directly on one of the sensor lines in the hopes that getting some steel close to the ground will trigger it. I’ve had mixed success with this. My normal operating procedure is to stop over the centermost part of a loop. Unfortunately, this is usually the greasiest place on the road, so you have to be careful. It’s not a good place to do a heavy stop. By the way, those heavy stoppers you mentioned may just be trying to get some metal closer to the road, not make their machines weigh more.

  Second, “modern” traffic light sensors, at least in my town, are little motion sensing cameras posted atop traffic light or street light posts. These work very well for motorcycles in my experience. Motorcyclists typically don’t have much clout with Public Works departments, but it never hurts to ask your local authorities to invest in new technology, especially if a particular intersection is slated for an upgrade.

  Third, the alternative to sitting at a recalictrant red light until you run out of gas or your bladder bursts is to treat it as an inoperative signal–stop, look both directions, and proceed when safe. It would be interesting to hear from your readers on how many do this, whether anyong has been ticketed for it, and whether they were able to fight the ticket using the “inoperable signal” defense. I ride to work early in the morning and sometimes get stranded at the signal on my offramp. If no one’s coming, I run it. The CHP office is just down the street and around the corner, so I’ll probably get to try the “inoperable signal” defense myself on of these days.

• I use the HP version of “light trigger” and it works for me. I ride a Yamaha 1100 Vstar.

  www.greenlightstuff.com

  How it works. http://www.greenlightstuff.com/tech.html

• I am a retired electronics technician.

  You have it right when you say that it is the mass of the vehicle and the inverse of the distance that have the greatest influence on the signal gain of the inductive loop.

  Since engineering in the US is at a very high level, I would expect the answer to this mess is for the highway departments to increase the sensitivity on the inductive loops by turning that small dial inside the switchbox at the intersection.

• These are adjustable in sensitivity, and are supposed to work for motorcycles. If you’re lucky, there will be just a few problem intersections on your ride to work – call the city and tell them about each one. I did this (Columbus, Ohio) and they sent someone out who adjusted the sensor (from a box by the side of the road) then checked it by swinging a shovel over it. Note that this is hardly a sensitive testing method, so it’s not surprising that loops differ significantly in whether they are triggered by motorcycles. Second note – Having this problem, I spoke to three different Ohio law enforcement officers on three separate occasions, one of whom was a motorcycle cop. All three said that if you are stuck through at least one full cycle of light changes, just LOOK CAREFULLY and go when it’s clear. If you by chance were pulled over for that, you would either not get a ticket or would have an excellent chance of having it dismissed. No kidding. If the light doesn’t change for a legally registered vehicle, it counts as defective and that’s the procedure for dealing with a defective signal.
• I have used the simple, magnetic light-tripper devices and they seem to work. I lived in Portland, Oregon, for a while and every traffic light in the whole city seems to be wired to such sensors. I was riding a BMW K75S at the time and just stuck the magnet in the chin fairing with a drop of glue to keep it from bouncing out. Could not have been an easier installation.

  A few points:

  1) The price is right because all you buy is a fairly powerful (for its size and weight) magnet. Given that’s all you are buying, the price should be even lower for these products.

  2) Since one seems to work pretty good, would two work better? I asked my smart nephew (PhD in high energy physics, builds atom smashers, knows a lot about magnets) what would be the best way to configure two ordinary magnets so they would be an improvement over a single magnet. His response was illuminating. He pointed out that since the strength of the magnetic field varies with the inverse of the square of the distance between the magnet and the sensor (like the gravitational attraction between two bodies decreases according to the inverse square law – look it up in your high-school physics textbook), it is better to have a weaker magnet that is close to the sensor than a stronger magnet that is farther away from the sensor. Since you cannot see the sensor buried in the asphalt, if you are going to use two magnets, it’s best to place them far apart but as low as possible on the frame or fairing of your bike. You want the magnets as low as possible to minimize the distance between the sensor and your magnet and you want the two magnets far apart to increase the chance that one of them will be closer to the sensor than the other. In brief, the distance between the magnet and the sensor is more important than the strength of the magnet.

  3) Mounting multiple magnets might be detected and interpreted by the sensor as multiple vehicles. Possibly a good thing.

  4) The magnets that I have seen sold as traffic light tripping devices have all been ceramic magnets, not iron or nickel. Ceramic magnets tend to have a more powerful magnetic field for their size and weight than do metal magnets. However, ceramic magnets are more delicate. Hit it with a hammer and you will get several smaller, weaker magnets. Trying to drill holes through a ceramic magnet to make it easier to mount on your bike probably would not work but you never know until you try. As I mentioned in (1) above, they’re cheap.

  5) It would be possible to create an electromagnet using a big nail, winding wire around it, and attaching the ends of the wire to your alternator. This would probably be total overkill.

  Thanks for running a great on-line news source and keeping a good attitude towards safety and riding.

• Hi, Alex,

  I love to read your articles, keep up the good work.

  I live in Quibec Canada and when i stop at the light, i position my motorcycle not in the center of the lane, but at the left, directly over the wire.

  That seems to work well.

You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.