BIKEPGH MESSAGE BOARD ARCHIVE

That's happened to me me.I rode across the intersection on my bike when there was no traffic.Option B or C would be,(in my opinion),the correct answer.

B.

I think there are times when it is judicious (and likely safer) to safely go through a red light rather than wait for the green and deal with traffic. I typically go through the intersection of Negley and Center during the pedestrian walk light because it gives me almost three blocks of separation from traffic. That seems far safer for all involved that dealing with rush hour traffic through that corridor.

Missouri recent passed a law concerning this issue:

http://www.cyclelicio.us/2009/08/new-missouri-law-cyclists-may-run.html

I usually follow B, but it depends on the situation.. if its late at night, I do B for my own safety, on my routes anyway, during the day, another car is along is 15-30 seconds that will trigger the light for me.

As a note, the lights are triggered by an induction loop, not weight, so when a metal object passes over them it creates an electrical current, triggering the light. Sometimes the loop is too deep or not sensitive enough to "detect" the amount of metal in some bike. Usually big steel frame bikes have no problem triggering lights, but carbon and some lighter aluminum bikes might.

B. I don't know where it's at, but i think there's the exception for bicycles and motorcycles in the law if they've been waiting

Usually big steel frame bikes have no problem triggering lights, but carbon and some lighter aluminum bikes might.

+1

I can't find it at the moment either, but I know there is an exception for bikes/motorcycles that says if the induction loop does not detect your bike, you can treat the light as inoperative/malfunctioning. At that point, for you, it bcomes a 4-way stop and you can go after yielding to everyone you should yield to. This does you no good, of course, if there is fast moving cross traffic that never stops, but it does give you the legal option to ignore the constantly red light.

Im not sure where its at either, but the law says if the light wont change you can assume it it malfunctioning and proceed with caution.

edit: guess i should read ALL the posts first sorry for repeating

I have this problem on ELB quite frequently. If a car doesn't show up within a few minutes or so, Option B is what I do.

I've often thought it strange that there are no buttons anywhere that you can push to cross the street. Where I grew up, they always had those on the light posts so that pedestrians could change the lights. However, I think that there could be a better design for bikes still on the street so that you don't have to wander over to a sidewalk to hit the button. That always used to bug me----but I will say that the street sensors back there were also pretty darn sensitive and that I could trigger them even with my lighter aluminum-frame bike.

It doesnt just apply to bikes, but all vehicles.

Section 3112:

Subsection C)

(c) Inoperable or malfunctioning signal.--If a traffic-control signal is out of operation or is not functioning properly, vehicular traffic facing a: (1) Green or yellow signal may proceed with caution as indicated in subsection (a)(1) and (2).

(2) Red or completely unlighted signal shall stop in the same manner as at a stop sign, and the right to proceed shall be subject to the rules applicable after making a stop at a stop sign as provided in section 3323 (relating to stop signs and yield signs).

B, usually. The light in Brighton Heights at California & Benton usually does not detect my bike.

The light I see most often, though, at Perry & Perrymont in McCandless, I apply B except when there's a car coming up behind me, wanting to make a left. I've been snarled at for "running" a red here (after sitting still for 30+ seconds), so I sit there out of spite, to teach people a lesson that the light sometimes does not detect bikes. Only when they lay on the horn, then I "run" the light.

Call me an ass if you want, but it's part of the mentality of being a cyclist in the car-dominated suburbs.

It doesnt just apply to bikes, but all vehicles.

@netviln's point is a good one. According to the code, you are a vehicle and have to comply with all vehicle laws unless there are special provisions in the bike section. So if it's not in the bike laws--then you follow the same rules you would in a car/truck tec.

http://www.dot.state.pa.us/BIKE/WEB/bikelaws.htm

From the PA guide to safe cycling - http://www.dot.state.pa.us/Internet/Bureaus/pdBikePed.nsf/infoChapterNine?OpenForm

WHEN TRAFFIC LIGHTS DON'T TURN

Always stop and wait for red lights. You not only ensure your safety, but also increase respect for cyclists as law-abiding road users.

But some traffic lights don’t turn green until they receive a signal from a metal detector buried in the pavement. A bicycle doesn’t have enough metal to make many of them work.

Recognize the detector by a square or octagonal pattern of thin lines in the pavement, where slots were cut for the detecting wires. The detector is most sensitive if you ride along one of the wires.

If your bike doesn’t trip the detector, you have to wait for a car to do it, or else you have to go through the red light. Going through the red isn’t against the law, because the light is defective. Refer to Sections of Title 75 (Vehicle Code in this pamplet) pertaining to pedalcycles Section 3112.

Detectors are made that work for bicycles, at little or no additional cost. Federal design guidelines exist for these detectors. If you put enough pressure on your local and state government, bicyclists can avoid the crashes and the city can avoid the lawsuits which may follow.

What neviln said. I try to stay out of the suburbs, so I don't run into this kind of light very often. I have only experienced this problem once that I can remember, and that was with the aluminum-framed tandem. I asked a pedestrian to push the walk button.

I have been told that the aluminum in your wheels should be enough to trigger the sensor, even with a carbon-frame bike, if you put the wheel sideways-ish, so more of it intersects the induction loop. Rather than try to find the exact spot where the pavement is cut, I just drop my bike to a 45-degree angle over the sensor wires. Works for me.

B, I ride home from work at night and this is a frequent occurrence, haven't had a problem yet.

Also, beware, if on foot or pedacycle, of the lights near the end of carson st, by the works. With all the construction going on and side streets closed some cars are treating reds like yields. Just saw a cop reprimand someone not ten minutes ago, the guy tried to run a red with the cop standing in the middle of carson street. The cop yelled 'Its red, when its green you can go.' as if speaking to a child.

I have been told that the aluminum in your wheels should be enough to trigger the sensor, even with a carbon-frame bike

Aluminum wheels with a magnetic loop sensor?

I used to have this issue on motorcycles, and I bought some rare earth magnets and put them on the bottom of my bike. $5 solution.

When it happens to me on a bicycle, I just wait until it's clear and go.

Thanks for the tips! I didn't realize it was induction. I just assumed it was weight. Cool!

The one I'm specifically thinking of is the one at River ave and the 30th St. bridge (from Herr's Island). That light takes forever to change anyway. Next time I'm up there, I'll try riding over the wires and see if I can get it to turn.

Next time I'm up there, I'll try riding over the wires and see if I can get it to turn.

Strictly speaking, it's the inside of the loop itself that is the inductor, so the wire edges don't particularly concern us.

I actually thought the idea wasn't induced current, as netviln said, but rather a change in induction. Induction depends on what the "core" of the inductor (e.g. wire loop) is made of (a metal will raise the inductance a whole lot). When you stand on top of an inductor (and are made of metal), it sees you as part of its core. So the traffic light circuit is just running an RL circuit and waiting for the value of L (inductance) to change.

On the other hand, I don't see how passing non-magnetized metal over an inductor would induce current.

Uh...end nerdy science nitpicking? Sorry netviln. Also if I'm wrong (could be) this'll be awesome.

yeah.. i was trying to generalize for the non physics and electrical engineering majors

I would also assume that non ferrous metal would not cause a change in induction and therefor not activate the light. But very few bikes have no iron or steel in them. Bottom brackets, bearings, chainrings, sprockets, etc.

I will say that I think I have had luck moving my bike back and forth over a loop to trigger the light, it could be my imagination tho. It would make sense tho since its the movement of the metal that changes the induction.

Non-ferrous metals don't cause a change in induction? Then how do metal detectors work?

Back to freshman physics!

The light at River & 30th just takes forever to change, is all.

The change in inductance has to do with the permeability of the material. So, I would think even dia- and para-magnetic materials should at least change the inductance, though maybe not as significantly as ferrous metals.

So if we're concerned about a bike not being quite enough metal to trip it, then non-ferrous metals probably aren't helping the case.

You know, we ARE on the internet - we could look this up. But that wouldn't be much fun, would it?

Kittens. Loop Detectors are tripped by kittens...

http://www.humantransport.org/bicycledriving/library/signals/green.htm

more than you probably wanted to know about this:

http://www.humantransport.org/bicycledriving/library/signals/detection.htm

very interesting post - I am always amazed at how many ppl think that those are "like scales" and detect weight when I always thought it was pretty much common knowledge that electromagnetics was the trigger.

in any case, with a stubborn sensor, try laying your bike down on its side between your legs while holding onto one side of the handlebar or brake lever housing

.....wow, actually this was a great review of physics b/c I (really) did forget that you need some electromagnetic material to trigger the coils. Thank you! (Seriously!)

Even so, I think that some are more sensitive that others. For example, in the neighborhood where I grew up, some of the intersections barely required you to stick the nose of a car over a small part of the trip area for the light to change. In other areas of the city, you had to sit there for awhile. And maybe that's not so much the coil, but rather the light timing.

Having a slippery (or slippy, as this is Pbgh) personal philosophy allows me to rationalize that once I stop and my foot goes down, I have become a pedestrian and am "merely" jaywalking when I run the red light on my bike.