I've got a small dilemma. Here's the scenario: At one of the 4-way intersections during my commute, there is a traffic signal that sometimes doesn't recognize that I'm there. In my direction (northbound), there is a left turn lane and a straight/right turn lane. It's not a very busy street, but the oncoming traffic (southbound) is pretty busy (most of them make lefts or rights). So in the morning, ocassionally I'll pull up to the light with no traffic behind/next to me, and I'll sit through three cycles before the light will change so that I can go. It sometimes remains red for me while the traffic coming at me is making lefts and rights. Not fair!!
So, without one of those buttons on the traffic signal pole to push, is there some way I can get the signal to recognize that I'm there, waiting patiently? I've tried riding aorund in a small circle, but even that didn't work. And just going through the red isn't really an option, as the oncoming traffic making a left is usually pretty heavy traffic (12-20 cars making the left)

Here in NC, I can usually see the sensor in the ground. I stop dead center in the lane, and I hear it works by detecting metal, and they always change for me.

On some streets though, mostly places with no stoplight, if I find that its hard to make a left, I make a right and then just merge over to the left and turn around. It adds maybe 5 min when I have to do it.

Around here there are two different types of traffic signal detectors -- metal detection and photographic.

The metal detection type are the most common. You can recognize these, at an intersection, by either a 5' diameter circular groove in the pavement or a similarly sized rectangle. Embedded in these are wire loops that are used to detect cars. To trigger this type of detector position your bike over the groove. Generally this will put you on either the left or right side of the circle as you position both wheels on the groove. Similarly, with the rectangular detectors line up your wheels on the groove.

The sensitivity of the metal detection sensors can be adjusted. If they are adjusted too high they will detect the car in the next lane. If they are adjusted too low, you cannot trigger them with your bicycle. I recently encountered one that I couldn't trip. After running the red light several times I called the city transportation department. The transportation department didn't do anything. So, I contacted the police department. Within a day they had a someone out adjusting the signal. I was fortunate to be there when they were adjusting the sensitivity. The signal was adjusted using my bicycle.

The photographic signal detector is new. You can recognize these by a small camera on top of the traffic signals. The camera will generally be towards the center of the intersection. Simply pulling up to the intersection should be enough to trip this detector; at least that is what the local transportation engineer told me.

BTW, I haven't seen a weight based sensor in over twenty years.

Try going across two of the lines. Rather than lining up straight at the lights, go for 45 degrees, I have a filter lane I ride through that was giving me hassle like that, put my two wheels across the rear and the right side lines and all of a sudden its now detecting me.

https://www.instructables.com/id/EL8EH6RZ1REP286X29/

eventually I'll get around to testing that myself

Thanks everyone! I'll give each idea a shot and hopefully I won't be waiting 3 or 4 cycles any longer.

I usually lay my bike down for a second, making sure the wheels are over the wire. It will trip them if the sensitivity adjustment isn't way off.

I have a camera sensor on my route (luckily not on a busy intersection) that NEVER detects me. So, I come to a complete stop, and check for traffic...and then I run it. I feel that I've fulfilled the intent of the law, and that's good by me.

A couple of good, strong magnets zip tied to the bottom of your down tube will do the trick, too.

magnets don't work it is not a magnitc signal they way it is a mass metal signal they detect.
I tested it out with a rare earth magnet that could handle 200# of pull in a 1" package. I put it right on top of the wire and no change.

I have one that sometimes does sometimes does not. going the otehr way it catches me most of the time.

OK. I had just heard about the magnet trick from a pal of mine that rides motorcycles. He said motorcycles can run into the same issue, with not enough metal to have the sensor detect it, and they sell this magent thing that you can bolt to the underside of the bike. It was supposed to have something to do with induction and the sensor. Sounded reasonable to me, but I don't know how those signal sensors work.

there have been several traffic engineer posts on hwo they work and they all say magnets don't work. and if putting a far more powerful magnet then is included in the overpriced products right on the wire does not work how will they work from a foot away?

a simple google search
https://bicycleuniverse.info/transpo/...g-signals.html
https://kutv.com/letbillbuyit/local_story_196170128.html

Our local public works folks tell me that if you ride up directly in the middle of the lane and stop at the white line, it will trigger the signal. If you can still see the pavement cuts for the sensor loop, this is easy, otherwise you'll have to guess where to go. I've tried this at the intersections on my commute and it usually works. Just be sure to stop, because if you keep moving, you'll move out of the sensor range, and the light won't change.

I'd call the public works department in your city, and try to talk to a traffic engineer. Every city does things a little different.

i think the magnet thing is to attach the magnets to the bottom of your shoe,then place your foot near the loop inbeaded in the road.

Some signals in some areas have light activated emergency traffic control signals. Emergency vehicles use this device to changes traffic signals. No idea how it works or what locales have them - I recall reading an article about a guy who bought one of these devices on ebay. The article was about him getting arrested for using the device.

I said all that to say this, I have one light that always changes to green for me as I approach in the dark- always. even if it just turned red seconds before. I have no idea why but my theory is that something about my approach with the helmet light on is triggering one of these switches. I've been looking for the sensor but I can't find it. :shrugs:

Magnets, unless they are extremely large...like say the size of a car, won't work for a couple of reasons.

One: a magnetic field on a permanent magnet decays with distance at a pretty fast rate, if I remember my physics correctly. You can demonstrate this for yourself by seeing how close a magnet has to be to pick up even a small iron object. It's measured in inches and fractions of an inch, not in feet. If you mounted the magnets on your tires, you might see some effect but that might be more due to the moving magnetic field (see below) then to the magnet. Mounted on your frame, it's just never going to work. It'd be better to affix it to the fuel line in your car for all the good it's going to do.

Two: the magnetic field you want to disturb is the one running around in the wires buried under the pavement. You don't disturb it by waving a magnet over it, you disturb it by sliding a big piece of metal through it. That's how the induction coil works. There is a wire buried under the pavement, probably less then an inch deep. There is a box over on the side of the road that is running a current of electricity through the wires constantly. In the box is a circuit that detects changes in the current of the electricity running through the coil in the pavement. This change in the current comes from moving metal through the magnetic field that is set up around the wires. Moving metal through a magnetic field causes a current change...it's the way that an electric motor or a generator works. When the box detects the change in current, it starts the signal cycle and, viola!, you get a green light! A permanent magnet, even a really powerful one, isn't doing anything that any piece of metal moving through that magnetic field isn't doing.

The...almost...surefired way to trip a loop signal is to be over the center of a dipole loop. Look at one the next time you are at a light. There is are usually two squares cut into the pavement (I haven't seen any of the round ones in Denver so I can't help you there). The wire for the loop is laid down in the lines cut in the pavement so that it is a continuous circuit, i.e. it's one wire. To accomplish this feat of engineering, you have to make a figure 8 out of the wire. In the middle of the loop, the wires pass over each other. The nice thing about magnetic fields is that they are additive, so when the wires pass over themselves, they double in strength. That means that on the center of the squares in the pavement (I know your eyes are glazing over but stay with me a while longer) the loop is also twice a sensitive. If you ride your bike, in a straight line, directly over the center for its entire length, you can almost always trip the light! But you have to be absolutely right over the top of the wires!

Now, you have been armed with knowledge! Go forth and do battle

Okay, I bashed the magnet thing above so here goes on the 'photographic' detector. These are photoelectric detectors - no camera involved. They are exactly like the detectors that are used at your local grocery/discount/big box hardware/etc store to magically open the door upon your approached. My neighbor even has a very annoying one on his garage that snaps the light on everytime I take the garbage out and blinds me so that I trip over my wife's hydrangeas when I take out the garbage...but never mind.

The problem with the detectors on the stop signals is, again, sensitivity. If they are set sensitive enough to detect a narrow target like a bicycle, then they are going to detect birds, people, moose, lions and tigers and bears! Oh my! Sometimes I can trip the one, and only one, that I have to deal with on my commute by doing a right or left hook just as I come to a stop at the white line. By turning sideways, I present a larger target and the detector works. It doesn't work all the time but it's often enough that I keep on trying

You might be on to something there. Look for the detector at the top of the light pole. It will look like a little camera or telescope about 6" long aimed at the street. Your helmet light might just sweep across it and make it trip. I have astronomy friends who have figured out how to turn off the street lights around their house by tripping the photodetector with a laser, these might work the same way.

I've had reasonable success at tripping the induction loop sensors with my trike, by making sure my rear wheel rolls over the wire. Of course, it could be the fact that the main boom is just inches from the ground, that the sensor trips.

Someone ought to invent a hand-sized EMP device that can be brought close to the coil, then detonated. Hmmmm, a 9V battery, a big coil and a massive capacitor ought to do it...

I just make sure I stop myself on one of the induction lines, not in the middle of the loop. Once I started doing this, I tripped the sensor every time.

All I can add here is that my Surly LHT has enough steel in it to trip every sensor I've ever ridde up to..... lots of steel in my tank-errrr I mean bike

Hmmm... Like I'm really going to stop, get off the bike...line it up over a sensor and lay the bike down in the street - in the rain or whatever...This time the DOT is over the top!

Yesterday, as I approached the traffic signal, i dismounted, laid the bike to the left and rolled the frame/wheels over the loop markings in the pavement. I righted the bike, and to my amazement, the light was green! With no one at the intersection! YAY!!