What do you do for underground traffic light sensors?
07-07-08, 12:32 PM
#26
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This is incorrect. Induction loops work with anything conductive. Someone says this EVERY TIME there's a question about this.
The induction loop is a big metal detector. Do you think metal detectors only pick up iron? They pick up zinc, gold, silver, aluminum, anything.
Any conductive OR ferrous material in the loop will be picked up by the coil.
I have an aluminum bike with aluminum rims, fork and handlebars; The only steel on my bike is the spokes (stainless, almost no reaction to magnets) random screws, the saddle rail and the drivetrain, but around here the *properly* adjusted sensors pick it up no problem.
The induction loop is a big metal detector. Do you think metal detectors only pick up iron? They pick up zinc, gold, silver, aluminum, anything.
Any conductive OR ferrous material in the loop will be picked up by the coil.
I have an aluminum bike with aluminum rims, fork and handlebars; The only steel on my bike is the spokes (stainless, almost no reaction to magnets) random screws, the saddle rail and the drivetrain, but around here the *properly* adjusted sensors pick it up no problem.
Most people don't realize...cyclists and motorcyclists...that you have to be directly over the sensor wire to trip them. Magnets do nothing to help whether they are mounted on your shoe, your bike, or if you grind them up and swallow them.
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Stuart Black
Plan Epsilon Around Lake Michigan in the era of Covid
Old School…When It Wasn’t Ancient bikepacking
Gold Fever Three days of dirt in Colorado
Pokin' around the Poconos A cold ride around Lake Erie
Dinosaurs in Colorado A mountain bike guide to the Purgatory Canyon dinosaur trackway
Solo Without Pie. The search for pie in the Midwest.
Picking the Scablands. Washington and Oregon, 2005. Pie and spiders on the Columbia River!
07-07-08, 12:42 PM
#27
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I don't see how it could be triggered by a magnet, unless there was a magnetic reed switch, activated by a movable slab that had a magnet attached to it, or some sort of magnetic field sensor. Both are doubtful.
The switches (at least around here) are usually triggered by weight. My old motorcycle didn't set some of them off (it was a light bike, at 550 lbs + my weight, 175 lbs = 725 lbs).
Options:
1. Ride a Huffy Roadmaster.
2. Eat at McDonald's every day for a month.
3. Stop, and if the light doesn't change, run it.
I always opt for #3.
The switches (at least around here) are usually triggered by weight. My old motorcycle didn't set some of them off (it was a light bike, at 550 lbs + my weight, 175 lbs = 725 lbs).
Options:
1. Ride a Huffy Roadmaster.
2. Eat at McDonald's every day for a month.
3. Stop, and if the light doesn't change, run it.
I always opt for #3.
No. They are not triggered by 'weight'. They are triggered by the movement of a mass of metal through the generated magnetic field which changes the current in the field and is picked up by a meter. No change in current (or too small to detect), no change in light status. Automobiles have a large metal mass and thus can cause a change in current from a long distance, relatively speaking. Bicycles and motorcycles have less mass (your mass makes no difference) and thus need to be closer to the sensor to make the current change. Running you tires directly...and I mean directly...over the sensor wire will cause the current change.
In the picture, the bike wheels are right over the wires. If you break the circuit on the short leg of the square or figure 8, the change in current isn't going to read as much more than noise and won't trip.
If you can't find the wire cuts in the ground, staria, you are hosed. Sometimes you can get lucky but if you are off to either side by even a little, the chances of tripping the light are slim. The wire cuts get buried during resurfacing of the road. However, you said this was a new light and I'm wondering if it's a motion detector rather then a coil. Those are much more difficult to trip. We are a narrow target. I find doing a little 's' curve at the light helps sometimes.
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Stuart Black
Plan Epsilon Around Lake Michigan in the era of Covid
Old School…When It Wasn’t Ancient bikepacking
Gold Fever Three days of dirt in Colorado
Pokin' around the Poconos A cold ride around Lake Erie
Dinosaurs in Colorado A mountain bike guide to the Purgatory Canyon dinosaur trackway
Solo Without Pie. The search for pie in the Midwest.
Picking the Scablands. Washington and Oregon, 2005. Pie and spiders on the Columbia River!
Stuart Black
Plan Epsilon Around Lake Michigan in the era of Covid
Old School…When It Wasn’t Ancient bikepacking
Gold Fever Three days of dirt in Colorado
Pokin' around the Poconos A cold ride around Lake Erie
Dinosaurs in Colorado A mountain bike guide to the Purgatory Canyon dinosaur trackway
Solo Without Pie. The search for pie in the Midwest.
Picking the Scablands. Washington and Oregon, 2005. Pie and spiders on the Columbia River!
Last edited by cyccommute; 07-07-08 at 12:46 PM.
07-07-08, 04:04 PM
#28
Cars are for the meek.
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Do the same thing I do on my bicycle or motorcycle.....wait until there is a car that pulls up....or run it.safely of course. I am not waiting all day for that D(*& thing to change, besides I did it right in front of a cop and he laughed at me. Whether that was out of my pure gumption to run it right in front of him or he was thinking the same thing...
07-07-08, 04:57 PM
#29
Full Member
The oregon bike manual has directions on triggering the lights on page 14:
https://www.oregon.gov/ODOT/HWY/BIKEP..._manual_06.pdf
Most bicycles contain enough metal to trigger the light, but you should know where the most sensitive spots are. Look for cut lines in the pavement, filled with tar. Depending on the shape, the most sensitive spots are: 1. Diamonds: just inside one of the points. 2. Rectangles: up front, in the middle. 3. Circles: about 1/4 of the way in. If you can’t trigger the light, either move forward to leave room for a car to place itself over the loop, or go to the sidewalk and press the pedestrian push-button (unless you’re turning left). You can also lean your bicycle over the loop so more metal is closer to the wires.
https://www.oregon.gov/ODOT/HWY/BIKEP..._manual_06.pdf
Most bicycles contain enough metal to trigger the light, but you should know where the most sensitive spots are. Look for cut lines in the pavement, filled with tar. Depending on the shape, the most sensitive spots are: 1. Diamonds: just inside one of the points. 2. Rectangles: up front, in the middle. 3. Circles: about 1/4 of the way in. If you can’t trigger the light, either move forward to leave room for a car to place itself over the loop, or go to the sidewalk and press the pedestrian push-button (unless you’re turning left). You can also lean your bicycle over the loop so more metal is closer to the wires.
07-07-08, 05:10 PM
#30
Bike ≠ Car ≠ Ped.
I'm sure that all the advice for positioning over the loops and pressing the crosswalk buttons isn't so helpful for this intersection since it doesn't have any of those things installed yet......
07-08-08, 03:21 AM
#31
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The 2nd link posted by cyccommute has a short blurb on video detectors, which it appears the op is dealing with. Apparently the person with the city thinks that video detectors cannot detect a cyclist, yet the author of the article says a video detector that doesn't detect a cyclist is inoperative and should be reported to the city....
And it's really amazing how many people don't know how different types of "demand actuated traffic signals" work. There should be a section on this in driver's ed or something. We have a few of the video detector ones around town, and more than one person I've talked with has been convinced the video detectors are red light cameras. At work we have vehicle gates operated by induction loops. Sometimes a pedestrian will want to exit through the vehicle gate, and will start jumping up and down in the center of the loop and/or waving their arms around. If I have an opportunity I'll try to educate them on how it actually works, but either way it's always good for a laugh
.
And it's really amazing how many people don't know how different types of "demand actuated traffic signals" work. There should be a section on this in driver's ed or something. We have a few of the video detector ones around town, and more than one person I've talked with has been convinced the video detectors are red light cameras. At work we have vehicle gates operated by induction loops. Sometimes a pedestrian will want to exit through the vehicle gate, and will start jumping up and down in the center of the loop and/or waving their arms around. If I have an opportunity I'll try to educate them on how it actually works, but either way it's always good for a laugh
.
07-08-08, 06:41 AM
#32
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Some people go through life never seeing anything around them or questioning how things work.
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