Not quite true, the inductive loop trigger senses a change in the frequency of the magnetic field. A car with enough conductive material will trip the sensor, a bike, doesn't have enough conductive material. A powerful enough magnet will trip the sensor.

There is an instructable on how to make one. It was intended for a motorcycle, buy you could easily make one for a bicycle.
Traffic Light Trigger

I'd say that more than 90% of the lights I come across trigger just fine for my Randonee... it's just a matter of sitting in the right spot and being patient... most of the lights I cross at are on MAJOR roads... with very long light cycles.

The magnet makes not one bit of difference. The induction loops are set up to detect the mass of metal moving through the inductive loop. Adding a little magnet, even a strong one, to a bike doesn't influence the current flowing through the loop.

Most people who say they can't trigger an induction loop don't know how. The best article I've found on how to trigger them is here. No magnets needed.

Yeah you might want to double check that, in case next time there is a ticket. In California if light is "broken" it can be legally treated as a yield.

In California the traffic courts would not consider such a light broken. During the rare times that a cop is nearby, use the crosswalk. Otherwise, run it. California has a very much zero-tolerance policy for red light running, especially where I live where it is a lucrative form of revenue.

I'd just scooch over to the sidewalk, push the button, and scooch back. Or run it. If cities are going to use sensor based lights there really should be a law allowing you to run them when they malfunction. It's not like they even work anyway: http://www.columbustelegram.com/arti...9359981032.txt

Detection of Bicycles by Quadrupole Loops

http://www.humantransport.org/bicycl.../detection.htm

How to Turn Signals Green

http://www.humantransport.org/bicycl...nals/green.htm

These are the best articles I've seen, and written by Steven Goodridge, PhD--an active member of bikeforums. (let's try not to hold that against him)

Most of these detectors work, but either the cyclist doesn't know how to trigger them, or the cyclist is too impatient to wait for them to switch the light. I've often geven up on detectors, ridden through the red light, then looked back to see the light finally turning green.

Well, that will teach me to open my mouth before I do research!

Hey, thanks for the links. I've always assumed my bike won't trip them, so I wait a suitable amount of time and treat it as a stop sign (defective light). If a car is coming up behind me I wait until it trips the signal for me. One thing I can say for sure, the colder it is, the shorter I wait.

Will try these suggestions and see what happens.

FWIW, sometimes they won't trip even in a car if you roll past them and stop too far up. A number of times I've sat at one in particular and as soon as I back up a few feet it will go.

Huh, boy was he looking for something to do!

I sit and wait. And probably look like a nerd as I wait for some of the city lights to go thru their set of changes - and if after a looooong set of seconds where it did not change for me, well then I go thru it (safely). My club actually has in a handbook written by a well known bicyclist of how to lay your bicycle down in the certain area so as to change the light. Ugh.

I like the idea of the magnet - have to look into it. But until then - I will wait, very impatiently, thru a series of lights and if my light doesn't change - I'll do it. But actually in a busy section, where I've been at lights where I have not triggered it and - it's gone thru the sequence and I don't make a difference - I have gotten pissed off and jumped sidewalks (busy streets). I do not normally do that.

This is kind of a problem I've been having. I am skeptical about every sensor I come across and simply assume it didn't detect me (because a lot don't). Some detect, some don't, so I just assume they don't and proceed through the intersection with caution when all clear.

It would only count if you're *convicted* of the offense the cop's charging you with. A ticket is a summons. If you send in the fine, you're pleading guilty. Tell them you want a trial, and show up at the court.

Also, if you are convicted of whatever it is, I believe you have 5 days (or ten???) to appeal it.

These lights are triggered by a change in electronic field density. Anything can change them as long as they are set to be sensitive enough. I regularly trigger the lights with my carbon fiber bike. There were a few lights in my area that couldn't be triggered with a bicycle but they been fixed. What I regularly do is to stand in the square cut out on the ground and wait for the light to change.

But do you have to show your drivers' license? If so, I might stop bringing it with me

Yeah, cops really like it when we make suggestions like that.

;)

Problem with that is where to park your bike while you go to court, and where to put your tools and patch kit that most of us carry with us since most courts these days won't allow you to carry tools into the courtroom. And I'm not about to leave my seatbag on the bike while I go into the courthouse. This does not take into consideration the hassle of having to take the time to go to court.

Bicycles and motorcycles, I'll either sit and wait and then make a judgement call, or I'll find a different route. Some signals that I've learned from experience that won't trigger for me I will just use them as a stop sign and proceed with caution.

Once when I lived in southern California I actually had an officer driving past on the main road as I sat there at a light to turn left tell me over his loudspeaker to just go when it's safe. He got a smile and a wave, and after that I never spent more than 10 seconds at that light.

If you're really in a ticket zone then just start logging calls to the roadway department, and keep a log of what number you called, when you called (day and time), and what light and direction the faulty signal was at. Then if an officer tags you again just pull out your little pocket pad and show him you've called in 30 times.

Excellent links, I will try the second link tomorrow morning (my ride home there is plenty of traffic to change the lights for me).

This is mainly a problem on my morning commute 'cause as I said I leave my house at 4am so there are not a whole lot of cars on the road. If it is still a problem I will report the light as defective, and use side streets to avoid this light.

You really shouldn't be asking someone in another country for information about your LOCAL laws. Do some research and find out.

This has been a problem in Portland (tickets) from what I've been reading, though I think it mostly has to do with the local Critical Mass rides causing problems (taking both lanes on a bridge, come on guys...).

They have also been targeting fixed gear bikes without a brake, which I kinda support as many of the fixed gear riders now are n00bs and really can't stop their bikes properly. For the more experienced fixed gear riders it is not a problem.

That's really funny. Since when do you need a driver's license to get a job? Half the people in NYC must be unemployed.

this happens on motorcyles ALL THE TIME.

a lawyer I know that specializes in traffic law, has won many many cases over the last 20 years, stating that "a traffic light that will not change for motorcycles, bicycles, or pedestrians, that causes them to cross the intersection against the light, illegally, is MALFUNCTIONING, and should be treated as any traffic light thats not working properly: it's a 4 way stop."

this is well documented in california traffic law (not sure about oregon) and I have beaten several tickets using that as my defense. (motorcycle, not bicycle mind you, but I don't think it makes a difference.)

(I dont have time to read all the replies if this is stated ignore me)

You can get a very high powered magnet and place it at the bottom of your bike and sometimes that does the trip. The magnet acts as a "huge object" for the sensors underground and can sometimes help you. I know motorcycles use these all the time. Should be no different for a bike.

As others pointed out there are ways to trigger the sensors. I have >90% success stopping on middle of the dipole sensors. Just a single aluminum wheel is enough for many of them.

Also consider that some left turn signals may require more than one vehicle to trigger, however in those designs you just don't get a protected left. Or others you have to get to more than a moment before the thru light turns green to get a left signal otherwise you have to wait a 2nd cycle.

So yeah, if you can't trigger it, then proceed as if a stop sign. But also call authorities and report it as malfunctioning.

Al

As I just wrote that is my experience too. Some major road crossings can take 3:30min to change after being triggered. 3-4min feels like a long wait.

Al