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How to make that light turn green

Posted by on December 8th, 2006 at 7:52 pm

A traffic signal technician at PDOT just released a really cool document titled, “Vehicle Detection: Or, Getting a Green Light on a Bicycle at an Intersection.”

Here’s an excerpt from the, “How we mark for bicycle detection” section:

“Whenever we receive a request to mark an approach for bicycle detection, our electricians use a bicycle to test the loops. Once we verify a location where a loop consistently detects a bicycle, we paint the spot with a temporary white mark in the shape of two small arrows facing each other (see Figure 3). Then we notify the good folks in the Pavement Markings Section and they put down a permanent mark with hot plastic in the shape of a small bicycle (similar to the bike lane mark only much smaller). There are some locations where the sensitivity of the loop has deteriorated and is unable sense a bicycle. We replace those loops as time and budget permit.”

The signal technician then offers some helpful hints:

“The detection does not lock in a call at most traffic signals. Therefore, you must stay on the mark because as soon as you leave the mark the traffic signal controller will drop your call for a green light and it may take another cycle before you get served.

Also keep in mind that some traffic signals have very long cycle lengths and it may take a while to get served on a side street. Cycle lengths may be as long as one hundred and twenty seconds and although two minutes may not sound like a long time, it may seem like an eternity when waiting for a green, especially if you are impatient like me.”

Here’s the full PDF (188K) with more details for all you signal detection junkies.

NOTE: We love your comments and work hard to ensure they are productive, considerate, and welcoming of all perspectives. Disagreements are encouraged, but only if done with tact and respect. If you see a mean or inappropriate comment, please contact us and we'll take a look at it right away. Also, if you comment frequently, please consider holding your thoughts so that others can step forward. Thank you — Jonathan

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Cheesus Christ
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Cheesus Christ

This is a good idea for an article, but sadly it does not point out the ease of getting a light to change, even with out the bike marking. We are becoming to reliant upon being told where and how to ride our bikes
Simply finding the cut out where the loop is, which is generally pretty obvious, and laying the majority of your bicycle( mainly frame) mostly flat to the road on top of it,will trigger most of these.
I have used this method for many many years myself, and it is generally very effective.
All intersections that work with this loop will work for bicyles, even if not marked, as long as you apply you bike frame properly.

Hi Class Ho
Guest
Hi Class Ho

What about non-ferrous frames like Aluminum, Carbon or Metal-Matrix? I think all the steel that’s left on my bike at this point are my shifters, brakes and drivetrain!

tonyt
Guest
tonyt

Been there, done that. I’m tired of these damn things. (sorry Jonathan)

I’m not going to sit there as some mindless detector decides whether it’s safe or not for me to cross while I’m getting rained on, late at night in the middle of February. Period.

These detectors are notoriously inaccurate and, well, damn frustrating.

I’m an adult. I can figure out what’s going on, and more than likely, it’s a better and safer use of my time to look for traffic and go. I stand there and try to get my bike to trigger some magnet and wham, some drunk comes up and nails me and . . . gets a ticket.

I appreciate PDOT’s effort, but it’s the car paradigm applied to self-propelled people. It’s dumb, and anyone who spends any significant time on a bike will more than likely agree.

A legal solution? Stop signs and red lights should = yield signs for bikes. That means on occasion we have to yield, but we don’t have to sit there looking like an idiot while some clock ticks. A decent trade if you ask me.

Rob Garrison
Guest

I don’t mind waiting on a light if I must. If I minded getting wet, I wouldn’t cycle this time of year. I don’t feel “like an idiot” for following rules meant for the safety of everyone on the road.

Caleb
Guest

For the most part, in practice, I agree with Rob. I’m happy to follow the rules. If nothing else, I think it serves to better relations between us and cars – It really annoys drivers to see “arrogant” (thier words) cyclists breaking the laws they can’t. On the other hand, I agree with tonyt for his late-rainy-february-night scenario. When I am on one of those side streets on off-hours with a 120-second cycle, with a questionably working loop, and there isn’t any traffic there, I am most certainly not going to wait for 5 minutes, and then give up and walk over to the cross walk, press the button, and wait another two, only to go onto the next intersection and do the same. Ack.

I commute mostly the same route every day and at similar times. I can learn which signals “work” and which don’t. Especially if it is cold and wet, I’m not going to waste my time waiting at a broken signal.

I had (wrongly) assumed that those little icons meant that PDOT had installed a special “bike sensor”. Knowing that it is just a mostly-works-for-bikes spot on the car sensor will make me even more impatient. They really ought to install a sensor engineered with bikes in mind, or, they shouldn’t expect us to respect the sensors.

Darrell
Guest
Darrell

Here is a potential solution to those of us with non-ferrous frames:

http://www.instructables.com/id/EL8EH6RZ1REP286X29/?ALLSTEPS

The comments listed after the instructable have good info in them as well. As it turns out, the person who came up with idea lives in Portland.

josh m
Guest
josh m

Rob, are you telling me that you come to a complete stop at every stop sign on side streets?

I ride main streets for the most part.. being that a lot of blind side street intersections have no stop signs and in NE people tend to just fly through them w/ their cars. Anyway, when I am riding w/ traffic, I stop at all lights and wait until I have a green.
When I am riding and there is no car traffic on either street, I go through the light.

Cecil
Guest
Cecil

I stop at all stop signs and I stop at all red lights. I patiently wait for the red light to turn, and if it doesn’t the first time around, I go over and press the walk button. I ride a steel bike and manage to trigger the signal most of the time, but sometimes I don’t. I would love it if the city could somehow install “real” bike sensors for those times when there isn’t also a car around to trip the signal, but frankly I am in never such a hurry that I feel the need to just blow the light. Call me an anal geek (or any other names you want) but I ride thousands of miles a year and have never been hit by car and never been ticketed. That said, is there any data on how much it would cost the city to adjust the sensors on the most heavily biked routes so as to ensure they would pick up even those fancypants steel-free featherwieght bikes? Or install a signal change button within reach of bikes, like the ones at 41st and Hawthorne, 17th and Umatilla, 41st and Burnside, 39th and Taylor, 82nd and Springwater Corridor, etc.?

Cheesus Christ
Guest
Cheesus Christ

The cost to make such things bike specific would be staggering, I am sure you folks would find.
And, inmy personal opinion, it would just turn out to be the pretty much the same thing.
The reality of the situation is you stop.
If it is safe, after looking, to proceed, do it.
If this is not your thing, or you realize it is not safe, wait out the light, or try to get the detector to work.
This issue is another fine result of bicycles being lumped together with motor vehicles by law.
The hardest part of changing bicycle yield laws will be the fact that we are required to follow the same rules as cars to a large degree.

Cecil
Guest
Cecil

Here’s something I have been pondering based on the various threads that have questioned whether it is proper to subject bicycles to the same laws and regulations as motor vehicles. Many posters have expressed frustration that those of us who rely on bicycles as our primary mode of transportation are not treated with the same respect as those who rely on cars. But are we really seeking equal treatment? Or are we looking to be accorded superior treatment? Some of the ideas posted, such as allowing us to treat red lights/stop signs as optional, are going to be viewed by drivers as granting us preferential treatment – allowing us “special rights,” so to speak. That, in turn, could lead to increased resentment, and more car on bike aggression, as opposed to less. . .anyway, just wondering what it is we are all really looking for here.

NPBike
Guest
NPBike

IMO…Bicyclists are the most difficult people in the world to please. Every positive story on this site about the city’s efforts to improve conditions is immediatley discounted as either a waste of time/money or having not gone far enough. walk before you run people…

Sara
Guest
Sara

Wow, I didn’t realize the sensors were magnetic. I have a Chro-moly frame, which I understand to be non-ferrous. So I guess I can’t trigger any of them. So far my solution has been to run over to the pedestrian crosswalk button, push it, and run back. But that is dangerous, so I don’t like doing it.

We do need a solution so that people are not encouraged (or forced, in some people’s minds) to run red lights. I don’t understand how running a red light can be safe. You could fail to see a car coming (say, if they don’t have their lights on), and the driver, not expecting cross traffic, wouldn’t even look for the cyclist. I think running red lights, whether in a car or on a bike, is one of the most dangerous driving moves. And not only is it dangerous, but it makes drivers angry with cyclists. I don’t want to deal with anti-cyclist drivers any more than I have to.

However, I can understand that some people may feel like they don’t have a choice if the lights won’t trip for them. Does anyone have better ideas than epoxying magnets on our shoes? What about a button placed on the ground that we could push, like a crosswalk button, depressed into the ground enough that cars wouldn’t drive over the button. However, I bet that would be very expensive.

Cheesus Christ
Guest
Cheesus Christ

Chrome Moly frames are steel, then chromed, by the way. A chrome moly frame will set off the sensors, I know, I own a few.
And I personally would not “run” a light, as would most not do so either.
The difference between running a light, and slowing, looking, then looking more (remember, left, right, then left again as we were all taught) then going through the clear intersection is great.
If you cannot properly gauge traffic, you should of course stop and wait for the light to change.
If the intersection is not clear, you should of course wait for the light.
if you continue to use the term”running a light” to refer to effective yeilding, you are doing us all a injustice.

Javen
Guest
Javen

Thanks for finding that. That was a fun read.

Cecil
Guest
Cecil

If the light is red, and you got through it, you are running it.

Adam-8
Guest
Adam-8

I don’t think cyclists are asking for superior treatment, just appropriate treatment. In some cases that may be superior to what cars are allowed, as in this case, and in other instances not. I just get sick of being subjected to rules that weren’t designed for me and don’t make sense for me to follow.
~Adam

Carl
Guest
Carl

“Chrome Moly frames are steel, then chromed, by the way.”

Yes. Chromoly is steel…but “chromed” it ain’t. Pity. Chrome is so pretty and shiny.

“Chromoly” just describes a type of alloy steel:
http://en.wikipedia.org/wiki/Chromoly

I can’t afford bikes that don’t set off these sensors.

mechanic Mark
Guest
mechanic Mark

I’m with you, Adam. Bikes are not cars, and should not be subject to the same set of rules. I don’t mean no rules, just different ones. As for “special rules” and “preferential treatment,” how about the multi-billion dollar freeway system which is closed to non-motorized traffic? I think a few concessions to bicycle traffic would hardly offset that gross imbalance. The freeway system is in place so that car and truck traffic can move freely, avoiding congestion on the smaller streets. Sensible laws for cyclists would allow bike traffic to move more freely, thus avoiding congestion on smaller streets. Hmmm…

Anonymous
Guest
Anonymous

Mechanic Mark, thanks for putting it under perspective. We are so used to cars and what it implies that we don’t realize how much goes into maintain the automobile network…

tonyt
Guest
tonyt

Carl, most bikes at Fred Meyer are aluminum anymore, so actually the notion that aluminum frames are the expensive ones is no longer true. Chromoly frames are now, more often than not, the premium ones.

Rob, I guess I didn’t do a good job of explaining myself and the situation to which I was refering.

I don’t feel like an idiot waiting for a light to change when I know it will change. But I know of a number of lights where the light WILL NOT change and the little sensors do not work. In my part of town, one offending intersection is heading south on Greeley at Portland (I think it’s Portland) where I once was waiting and daydreaming away before I realized that I had sat there while the light cycled through 3 times without giving me the green light. At that point I AM an idiot if I just sit there like a well-trained monkey waiting for the light that won’t come. I’m sorry, at that point I’m just going.

And yes Sara “running a red” light is dangerous, but no more dangerous than passing through any intersection that doesn’t have a light. And the false sense of security that a green light seems to give some cyclists can be deadly. You need to be very aware as you approach ANY intersection, regardless of what the light says. I know more cyclists (myself included) that have been hit when they have the green light then have been hit for running a red.

Sara
Guest
Sara

tonyt, I think your concern with any intersection is exactly why I am concerned with running red lights or effective yielding at red lights. Whether I am in my car or on my bike I am aware as I approach an intersection. I have seen too many motor vehicles completely blow through a red light not to. I think what makes people able to safely interact on the roads is predictability. So any time someone does something other road users wouldn’t expect (even when necessary), it makes me worried.

But like I said, something needs to be done about this. Effective yielding, running over to the side to hit the crosswalk button, sitting there for ages waiting for a motor vehicle to arrive, laying the bike down on its side, wearing magnets on your shoes, none of these are real solutions.

Mr. Know it All
Guest
Mr. Know it All

I hear Lars “Bike-Hater” Larson badmouthing the money spent on any transportation project that isn’t specifically for automobiles. Thus, I’m sure he would resent cyclists even if every one followed the law. He would resent cyclists because of the money spent on bike lanes, bike lane signal sensors, bike trails, bridge crossings and anything else for bicycles. He’s said so many times on his radio program (station is 750 AM). Soooo, why follow the rules made for cars? Those people who are stupid enough to hate cyclists will still hate you! (One reason to follow the rules is that the cops are also stupid and hate cyclists and will give you a ticket for a frivilous violation to prove it! They do have the power so you cannot fight them.)

To treat red lights/signs as yields is not asking for superior treatment – it’s just practical for bicycles. Especially for stop signs. Stop lights perhaps should be treated as stop signs and no, you do not have to put your foot down in order to “stop”. If you slow to less than 2 or 3 mph that is the same as a “stop” when you are talking about a bicycle. There is nothing superior about it- it’s just practical. Those who are competent on a bike understand this – those who are not competent on a bike do not understand it. THAT’S OK – let those people ride as if they are driving a car – there is nothing wrong with that if that is their choice – but competent riders will choose to go when it’s safe. It’s just practical.

Cecil
Guest
Cecil

Obviously we all have our points of disagreement on this, but do not assume that those of us who obey the letter of the law do so because we are not “competent” riders.

Cheesus Christ
Guest
Cheesus Christ

In the city of Portland a track stand is considered a stop. You don’t have to put your feet down.

SKiDmark
Guest
SKiDmark

And while you are stopped doing a trackstand, Barnum & Balzey will come along and give you a ticket for no brakes.

Two ways to handle if the sensor won’t work: Look both ways (for cops) and go. Or roll up on the side walk, hit the walk button and wait about 30 thirty seconds and go with the blessing of following the rules.

Chromoly frames are ferrous, a magnet sticks to them, Stainless can be non-ferrous, and so is titanium.

Roger Geller
Guest
Roger Geller

Non-ferrous frames will be detected by the sensor. There is enough steel in the drivetrain to do that–at least at the loops that have been made especially sensitive. It’s not particularly expensive to sensitize the loops. We send out a crew with a bicycle and they find the hot spot and then make it hotter, if needed.

I’m not aware of any special bike loop; these are just the standard loops adjusted to make them more sensitive and/or marked to let cyclists know where the hot spot is.

If you find a loop that’s not working for you–either marked or not–call the bicycle hotline: 823-CYCL, or send in a request via our website: http://www.portlandonline.com/transportation/index.cfm?&c=34818; we’ll then adjust and mark the loop.

josh m
Guest
josh m

Some of us use our ears, just not our eyes, at intersections… that’s how you know about cars w/ out lights, or blind intersections. works for me. I’ve yet to be hit breaking these laws, only when I’m following laws do I get hit or almost hit.

Bill Kloos
Guest
Bill Kloos

I manage the Signals & St. Lighting Division for the City of Portland. Just to add a little more beyond what Roger has already added.

First, our inductive loop detectors are activated by materials that conduct electricity, but don’t need to be ferrous. Aluminum will be detected. This article provides more technical details.
http://www.humantransport.org/bicycledriving/library/signals/detection.htm

Second, our goal is to have all of our inductive loops detect bicycles as well as cars. Our 6′ diameter round loops are capable of doing that with the special electronics that we use. As noted in the first response post above, you don’t need to have the bike marking to activate the signal. We put in the markings to make it clear where you should place your bike. If there are no bike markings, just remember to “put your tires on the wire”. The scare in the pavement covers the buried detection wires, and is generally the most sensitive part of the detection field.

Third, if you find a signal approach that’s not working for you, let us know! Use the contact info noted above by Roger. If we don’t know it’s broken, we can’t fix it.

Garlynn
Guest

I’m with Tony. We need to change the laws to match existing behavior:

http://undergroundscience.blogspot.com/2006/12/lets-expand-idahos-bicycle-code.html

More specifically, we need to take Idaho’s proven law (referenced in the link above) and just wholesale adopt it in Oregon.

In fact, this should be a priority for the upcoming legislative session, now that there’s a Democratic majority in both houses as well as a Democratic governor!

Who’s willing to help make this happen?

cheers,
~Garlynn

one road one set of rules
Guest
one road one set of rules

Aside from if the city should or shouldn’t be spending more or less money on traffic control devices.
I am a firm believer that as long as a traffic device is in place you should obey it no matter what vehicle you are on.
If you don’t like the set of rules stay off the road, or get the rules changed.
Don’t break the law just because it’s not meeting your needs.
I do not think anyone should get special treatment no matter what the vehicle of choice is.
One road one set of rules

Cecil
Guest
Cecil

Josh said “Some of us use our ears, just not our eyes, at intersections… ”

Funny, I would say the majority of the bikers I have seen blowing stop signs and red lights have had iPod/Walkman/mp3 player headphones on/in their ears. They may be using their ears, but it obviously ain’t to listen for cars.

adam
Guest
adam

BTA has a mission to do this. http://www.bta4bikes.org/at_work/statewideadvocacy.php

not sure why they are unsuccessful. anyone know why they cannot make change happen?

Eli
Guest
Eli

make sure that Inductive-loop traffic detector detects you.

http://science.discovery.com/brink/kip-kay/green-light/green-light.html

link to how to make your car get through lights