Tripping Traffic Light Detectors (again . . .)

[bmurphypdx]

Here's an interesting short video with information I hadn't heard before:

Linky

 

The "secret"? - Placing your wheels on the edge of the detector loop.

[mneblett]

Works well if you have steel wheels (like a bicycle wheel rim).

 

Not so good with non-ferrous wheels (like our Al alloy wheels) -- the detectors don't see them.

 

You can try holding your centerstand down with your left heel against the pavement over the loop, but even that may not be enough steel -- that never worked with one particular light near my house. Fortunately, my city is going away from in-ground induction loops to optical detectors mounted up on the bar that holds the stop lights -- at least with these I have a slightly better chance of finally getting a light to change.

[upflying]

No secret there, that's how I do it. If all else fails, go through the red..carefully. Unofficial advice of course.

[Dave39]

Works well if you have steel wheels (like a bicycle wheel rim).

 

Any bicycle with steel wheel rims must be an antique or Walmart special....even my heavy touring bicycle has AL alloy rims.

 

http://en.wikipedia.org/wiki/Bicycle_wheel

[Mister Tee]

I use the kickstand trick - I set the kickstand down on the loop. Works pretty well.

[motorman587]

Or make a right turn, and then a u-turn, where/if legal.

[4wheeldog]

When all else fails, I have had some success with shutting off the bike and restarting........The electromagnetic action of the starter operating can be enough, sometimes.

[CarrotNC]

...city is going away from in-ground induction loops to optical detectors mounted up on the bar that holds the stop lights...

 

I was curious how they worked, so googled a bit and found ITS Signals, check on the bottom right for Vehicle Detection.

[nrp]

It is only a requirement that the wheel rim conduct electricity to change the inductance of the search coil. The rim(s) need not be magnetic. (Lenz Law effect)

 

There is also an effectiveness that is inverse to the distance between the metal and the coil. That's why the kickstand placed directly on top of the coil is effective even though the amount of metal is small.

 

Otherwise the video is technically accurate per what I found talking operating details to another engineer at Traffic Control Corp (or something like that) a couple of years ago.

[basilr]

I just found this on the City of Reno Nevada site. It may just be a new use for a coat hanger, who knows. It could be held on with a magnet, that is also supposed to work.

 

"How come the detector won't pick up my motorcycle?

 

With very small vehicles such as a mo-ped or some motorcycles, the detector may not be sensitive enough to pick it up. Most cyclists do not notice a problem during the day as there are enough regular cars to actuate the loops. The problem becomes very apparent at lightly used intersections or in the early am or evening. Make sure you are stopping in the correct location, that is behind the white line or crosswalk. The most sensitive areas of detection are to either side of the lane, not in the middle. Machines made mostly of alloys or aluminum that are high off the pavement will be more difficult to detect. While signal staff has not verified it by experiment we have been told by police officers that installing a small loop of wire with several turns (go around in a circle two or three times) about nine inches to a foot in diameter under the frame of the motorcycle parallel to the roadway surface will make the detector work every time".

[mneblett]

It is only a requirement that the wheel rim conduct electricity to change the inductance of the search coil. The rim(s) need not be magnetic. (Lenz Law effect)

That's the difference between theory and the real world. Different materials differ greatly in their effect on a field -- in my experience, with Aluminum, unless you have a big bloody chunk of the stuff right at the ground, it is totally unnoticable to a ground induction loop. So, my comments were directed to what reliably works -- either a lot of steel (like a car) or something that can generate its own E-field (starter, running current through a wire loop, etc.). My RT's wheels and engine certainly don't qualify!

[scaudy]

What about an item called signal sorcerer? Supposed to be a small highly magnetic piece of metal that will trip the light. I have one but can't say for sure if it has an impact. I can say though I very rarely get caught by a light I can not trip.

[4wheeldog]

What about an item called signal sorcerer? Supposed to be a small highly magnetic piece of metal that will trip the light. I have one but can't say for sure if it has an impact. I can say though I very rarely get caught by a light I can not trip.

 

I had a signal minder.....Same idea as your sorcerer. It didn't seem to do much, so being a good old 'merican who believes "If some is good, more is better, and too much is just right" I hung a fair sized rare earth magnet in the bottom of my fairing. Didn't do a damn thing.

I am going to try the wire loop though......Not that we have many traffic signals here in the NM mountains, but I do travel from time to time.

[Peter Parts]

Old, sad topic.

 

Toronto is a beehive of bicycle enthusiasm but sure hasn't clued the city elders to the problem of the many loops around here.

 

Complaining might help. When I have, the authorities swear they will send a technician out to raise the loop sensitivity a notch. Not sure I've ever found a difference, but feels good.

 

My understanding is that when there is a "failure" of this sort, you can legimately take matters into your own hands and do what you must. Often you have to break some law when stuck at a loop, so it might as well be the law that gets you on your way best.

 

Hard to do a comprehensive "study" of this problem. My impression is that no advice I've ever heard works. And I am generally quite an optimist.

 

Oddly cool in Toronto. And this is hard even on an optimist.

[EddyQ]

It is only a requirement that the wheel rim conduct electricity to change the inductance of the search coil. The rim(s) need not be magnetic. (Lenz Law effect)

That's the difference between theory and the real world. Different materials differ greatly in their effect on a field -- in my experience, with Aluminum, unless you have a big bloody chunk of the stuff right at the ground, it is totally unnoticable to a ground induction loop. So, my comments were directed to what reliably works -- either a lot of steel (like a car) or something that can generate its own E-field (starter, running current through a wire loop, etc.). My RT's wheels and engine certainly don't qualify!

 

How about a big sheet of Mu-Metal? This stuff has higher permiability than steel.

 

Anyone know the frequencies used by these loop detectors?? A loop with the same frequency mounted under the bike should be very effective. But, I think the frequency is not consistant and therefor you may need to detect the frequency first.

[Selden]

I have had reasonably good luck with two techniques:

 

1. Approaching a light with a loop detector, just before stopping, ride diagonally from full right side of the lane to the left side. This moves the motorcycle's mass over several detectors, often with the desired result.

 

2. While stopped over a detector wire, fan the center stand.

 

If technique neither works, either jump off the bike and run over to a pedestrian cross button (and hope you can get back on the bike before anything happens), or wait until no traffic is visible in either direction, and drive through the red light.

[nrp]

The signal control people told me that mu-metal would not be of any advantage when compared to regular metals. They emphasized that it is not a magnetic sensor.

 

The frequency of the loop excitation is in the tens of KiloHertz. It is adjustable by the user (why??), but the number of 80 KHz sticks with me as being typical. It is surprisingly high.

 

Maybe a copper disc/plate?

[Spike]

Red light? What read light?