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Old 01-26-14, 02:26 PM   #1
natnat
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In what cities do traffic lights not detect bikes AT ALL?

I'm working on a device that will trigger inductive loop sensors at traffic lights. I'm testing it in the South Bay, where 80% of lights DO detect bikes. I want to test it in a city where no intersections detect bikes -- that would be a harder test to pass.

Do any of you know of cities, preferably within Northern California, where the cities don't tune their traffic loops to detect bikes?

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Old 01-26-14, 06:46 PM   #2
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There are always a few lights on my rides that don't turn. But not a city or township as a whole.

I always wait at lights for a cycle. If it doesn't turn, then I'll run it when traffic is clear. But I always give it a chance. It would be a lot better if there was always a sensor that would detect bicycles and change the light.

Best of luck on your project!
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Old 01-27-14, 11:14 AM   #3
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I've always had a lot of trouble with the lights in Belmont, CA. They are just off the Caltrain station, I'll try and mark out the ones I have trouble (as in 0 success) with on a map.

Edited to add:
I can't seem to pin and link a map. I've not been able to trigger the light at the intersection of Ralson and 6th Avenue, coming down Ralston and turning left onto 6th Avenue. The other one is coming down Oneill avenue and turning left on El Camino Real.

Last edited by treadtread; 01-27-14 at 11:19 AM. Reason: ..
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Old 01-27-14, 01:30 PM   #4
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Monterey. There are many sensor lights, especially for left-turn lights, and none of them detect bicycles.
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Old 01-27-14, 08:51 PM   #5
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How are bikes generally detected? I know some of the signals work by camera, which has nothing to do with loops in the road. Also, the detector loops in the road usually work by detecting metal objects (cars). CF bikes don't usually set those off. To me, it's all a crapshoot, and I have no idea when I'm being detected, and what I'm being detected by...

I'd like to know more what you're trying to do, and how this could work with current bike technology.

EDIT: So to answer your specific question, there seem to be problems with detections in almost every city I ride through, I notice it more on my scooter.
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Old 01-28-14, 02:33 AM   #6
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Could it be weight that detectors sense? Once, I turned left onto El Monte by triggering the light from Foothill Expressway and a (much thinner) rider marveled to my chagrin that he couldn't do "that" (like I had really "achieved" something).
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Old 01-28-14, 09:44 AM   #7
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Quote:
Originally Posted by SClaraPokeman View Post
Could it be weight that detectors sense? Once, I turned left onto El Monte by triggering the light from Foothill Expressway and a (much thinner) rider marveled to my chagrin that he couldn't do "that" (like I had really "achieved" something).
http://en.wikipedia.org/wiki/Induction_loop

The relatively crude nature of the loop's structure means that only metal masses above a certain size are capable of triggering the relay. This is good in that the loop does not thus produce very many "false positive" triggers (say, for example, by a pedestrian crossing the loop with a pocket full of loose metal change) but it sometimes also means that bicycles, scooters, and motorcycles stopped at such intersections may never be detected by them (and therefore risk being ignored by the switch/signal). Most loops can be manually adjusted to consistently detect the presence of scooters and motorcycles at the least.

I know some roads have bike lanes between the straight through lane and the right turn lane, and within those, there is either a loop, or the camera focused on the bike lane is set to detect bikes. Most of the roads I ride on that have signals, usually also have enough traffic that I can wait for a car to trigger the signal. Other times, I'll just go to the crosswalk and hit the ped button.

I would like to know how the OP plans on helping detector loops detect CF bikes.

Last edited by cthenn; 01-28-14 at 09:51 AM.
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Old 01-29-14, 11:19 AM   #8
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Most signal light detectors sense metal. Motorcycles have this problem as well. A popular fix for this is to attach a magnet to the bottom of the bike. I assume the OP is working on something of this nature.
I had a light in my town that would not sense my motorcycle and I mentioned it to a CalTrans worker who said he could adjust the sensor which he did and now it works for motorcycles.
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Old 02-05-14, 03:09 AM   #9
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i always dread turning left at a light on my motorcycle for this exact reason. one trick to getting the light to change when on a motorcycle is to put the kickstand down directly on the loop and stand up off the motorcycle, but thats obviously not a fix for a bicycle. when im on my bicycle, i just usually make my way over the the pedestrian indicator to get the light to change.
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Old 02-08-14, 08:53 AM   #10
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Thank you for all of these responses! I'll definitely check out Monterey. Since Belmont is close, I'll check that one out the cited intersection there too.

The device I'm working on scans all the legal frequencies that the inductive loop sensor may be operating at, then when it finds a signal, it sends back a reflection signal, just as if a car (a big metal mirror) would. An LED will light when the lock is achieved, letting the cyclist know that the bike has been detected.

Eventually we'll have a model for motorcycles too.

Thanks again!
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Old 02-09-14, 12:01 AM   #11
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if you have a link or anything on your project, i can post it up for you on bay area rider's forum if you like. i know a good amount of people over there would be more interested in this than the majority of cyclists, just because its easier to ride over and hit the pedestrian cross walk button on a push bike than it is to get off your motorcycle and do the same.
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Old 02-11-14, 07:06 PM   #12
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Quote:
Originally Posted by kelsodeez View Post
if you have a link or anything on your project, i can post it up for you on bay area rider's forum if you like. i know a good amount of people over there would be more interested in this than the majority of cyclists, just because its easier to ride over and hit the pedestrian cross walk button on a push bike than it is to get off your motorcycle and do the same.
Damn hooligans. Buzzing on their fancy shmancy motorcycles on isle of 9.
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Old 02-13-14, 05:13 PM   #13
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You can generally make a loop detector work with carbon fiber bikes by just making sure the chainring/chain are over one corner of the loop. The chain is usually made of steel, so should be detected if the loop is sensitive enough.

The ingenious device to trip the loop detector may be coming just in time to become obsolete. I see more and more intersections have the cameras set up to trip the lights (the technology has gotten a lot cheaper, and they no longer have to dig into the asphalt and lay a wire). I find they are even less likely to work with bikes, since we present such a narrow head-on profile, about the same as a ped crossing the street, and they wouldn't want peds to be able to trip the lights. I have tried placing the bike sideways, but it could be risky if the light changes just as a motor vehicle approaches, having to get the bike straightened out, with the driver wondering why the heck you've got the bike sideways. At night, you cannot trip them by aiming your headlight beam at the camera (I've tried).

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Old 02-13-14, 06:07 PM   #14
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You can generally make a loop detector work with carbon fiber bikes by just making sure the chainring/chain are over one corner of the loop. The chain is usually made of steel, so should be detected if the loop is sensitive enough.
Loop detectors work with any electrical conductor - aluminum works fine and almost all bikes still have aluminum brake tracks. In fact some of the folks who come out to adjust the sensitivity of the detectors after complaints are made by cyclists just bring a single rim and lay it over the detector area. It's easier than for them to bring out a whole bicycle and gives similar results.

Locally the town south of us is experimenting with a microwave detection system that detects bicycles separately from other vehicles. That way the traffic lights can be adjusted to give cyclists enough time to clear the intersection when they are present but to have a shorter interval when there are no cyclists.

Last edited by prathmann; 02-13-14 at 06:14 PM.
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Old 02-14-14, 04:14 PM   #15
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Quote:
Originally Posted by cthenn View Post
How are bikes generally detected? I know some of the signals work by camera, which has nothing to do with loops in the road. Also, the detector loops in the road usually work by detecting metal objects (cars). CF bikes don't usually set those off. To me, it's all a crapshoot, and I have no idea when I'm being detected, and what I'm being detected by...

I'd like to know more what you're trying to do, and how this could work with current bike technology.

EDIT: So to answer your specific question, there seem to be problems with detections in almost every city I ride through, I notice it more on my scooter.
pretty much my experience as bicyclist and motorcyclist. i'm often forced, even on my motorcycle, to resort to treating a light as a stop sign. i'm waiting for the time i get pulled over and must explain myself. i hope the LEOs are taking note.
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Old 02-14-14, 04:19 PM   #16
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Loop detectors work with any electrical conductor - aluminum works fine and almost all bikes still have aluminum brake tracks. In fact some of the folks who come out to adjust the sensitivity of the detectors after complaints are made by cyclists just bring a single rim and lay it over the detector area. It's easier than for them to bring out a whole bicycle and gives similar results.

Locally the town south of us is experimenting with a microwave detection system that detects bicycles separately from other vehicles. That way the traffic lights can be adjusted to give cyclists enough time to clear the intersection when they are present but to have a shorter interval when there are no cyclists.
this his caught me out a couple of times. the "smart" lights sometimes, when they out"smart" themselves, leave the light green for only a second or two. i'm convinced that this "feature" is the cause for a number of otherwise inexplicable automobile accidents (some fatal) in the Contra Costa county area. like the intersection of Marsh Creek Road and the route 4 bypass around Brentwood. people don't expect lights to stay green for only a second...

my apologies for the mostly OT post. i suppose it should be in another forum.
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