traffic signal actuators

[mimitabby]

this is true in Seattle; not sure about where you live:

"As far as bicycle detection is concerned, I suggest that you center the bicycle in the center of the lane with the front wheel approximately 2 feet from the stop bar or crosswalk bar. If you have a particular intersection that does not seem to "see" you, I would like to know about that as well. We are often able to change the sensitivity of the detector to help better detect bicycles.”

I received this information from a city streets employee.

oh, and hey, on some of them, it works.

If any of you seattle people know of a bad actuator, PM me and i'll give you the lady's email and contact info

[Thorn]

Most major cities and/or counties have a similar contact person. Our local contact was so helpful he managed to get a light just outside of his jurisdiction adjusted.

In Wisconsin we have a 45-second rule (might be 30-seconds, but I give it 45just to be safe). If a motorcycle or bicycle is at a signal-controlled intersection without any motor vehicles to trip the switch and they have waited 45 seconds, we can legally run the red light.

However, the intersection I reported has 55mph traffic (posted speed limit, so you know they're going faster) on a curved road with a slight hill to make visibility even worse. I requested that the sensors be adjusted and now have no trouble getting the light to switch. Much nicer. Take the time--it is worth it.

[JaneE]

Gee, I never knew this was even possible!

We live in a semi-rural area with a number of intersections with this types of signal control (as well as 55 mph speed limits). When there are reasonable breaks in traffic we've been known to, on occasion...ahem...run the red light. Otherwise you could sit there until H*ll froze over waiting for the green light if another car didn't happen along.

I will definitely pursue this. Thanks!

[OakLeaf]

There are two types of signal actuators: the new optical ones (lives on top of the light, and looks similar to a red-light camera), and the old magnetic ones. I'm pretty sure it's impossible to trigger a magnetic actuator unless you have a steel frame. Traffic authorities are supposed to adjust the sensitivity of the actuators, but they're not going to replace their whole system.

I'd give it longer than 45 seconds, too, many lights have a longer cycle than that!

Also, if you're at an intersection that has some traffic so there's a car behind you, pull way up so that they can trigger the light. A lot of times cars hesitate to get too close, so beckon, and holler at them if they don't get the message!

[kelownagirl]

I wonder if that works here too? Ours are magnetic... We usually have to go over and push the cross walk signal to get the light to change. If there's no traffic, I sometimes run the red....

[mimitabby]

Also, if you're at an intersection that has some traffic so there's a car behind you, pull way up so that they can trigger the light. A lot of times cars hesitate to get too close, so beckon, and holler at them if they don't get the message!

I used to do this too, just pull up way forward IN CASE a car would come, as well as staying to the far side of the lane, so i would miss the actuator!!

now i just go right for the center of the lane and IT WORKS! (but not all intersections)

[Eden]

There are two types of signal actuators: the new optical ones (lives on top of the light, and looks similar to a red-light camera), and the old magnetic ones. I'm pretty sure it's impossible to trigger a magnetic actuator unless you have a steel frame.

This is a common misconception, but the buried type of traffic detectors use induction (similar to a metal detector), not magnetism or weight. Any type of metal will set off an induction loop, so an aluminum or ti frame should set one off just as easily as a steel one (I suppose if you could drag around a bike made of gold that would work too ;) ) . Even a CF bike, if it has metal rims/spokes will set trigger a traffic light that is set up to be sensitive enough.

If you can see the cut out in the road the best place to position yourself is along the edge of the cutout, front wheel angled along the top of the cutout, the whole bike leaned a bit into the loop. Basically making the metal parts of your bike look as big as possible to the detector.

[Pax]

I had a guy on a motorcycling forum suggest a strip of rare earth magnets sandwiched between two strips of electrical tape. I put it on with zip ties and it works like a charm.

[mimitabby]

oh yeah, and a bike buddy of mine told me that he saw a Seattle traffic engineer working at an intersection with a bike wheel in hand, checking the actuator!

[kfergos]

This is a common misconception, but the buried type of traffic detectors use induction (similar to a metal detector), not magnetism or weight. Any type of metal will set off an induction loop, so an aluminum or ti frame should set one off just as easily as a steel one (I suppose if you could drag around a bike made of gold that would work too ;) ) . Even a CF bike, if it has metal rims/spokes will set trigger a traffic light that is set up to be sensitive enough.

Huh. I have a light I go through that recognizes me on my steel bike, but never on the aluminum one. :confused:

Speaking of solid gold bikes: http://living.oneindia.in/automobiles/two-wheelers/2008/eco-friendly-bike-060608.html

Also, I think here in Massachusetts, you have to wait two minutes before it's legal to run a red light. Two minutes feels like an eternity!

[TahoeDirtGirl]

There is another type of traffic signal. Timed. I have alot of timed lights where I am. You can always tell they are timed because at 3 a.m. they always change for a car that just isn't there. I happen to like these because I don't have to figure out where to stand or if it can see me.

[sb-gal]

Sometimes - if I'm the only person (read no cars) I don't stop :eek:. Of course I make sure NO one is coming. I do the first part of my commute at 6:30 am. Most of the lights on the commute should be stop signs, there's just no enough traffic to justify stop lights. Perhaps 5-6 times a year they're necessary if a big event is in town. I never go through the big ones on a red, too risky.

If I do have trouble getting a light to change or if I have my son with me (I never even run stop signs with him, bad example :D) I will hit the crosswalk button and then re-align myself on the road.

[PscyclePath]

Here in Little Rock we have mostly induction actuators, where they work best if you position your bike directly over the cut that's perpendicular to the roadway. The work okay with my steel Surly and the aluminum mountain bike, but they balk at recognizing my CF road bikes.

Of course, the engineering wizards in the city Traffic Division position them six car lengths in front of the red light, so they only work when you have at least 5 to 6 cars backed up... :mad:

Tom

[pardes]

I'm trapped in my subdivision behind two actuator traffic signals. Like Blanche in "Streetcar Named Desire," "I've always depended on the kindness of strangers" for their cars to trip the light. But now that I'm commuting to work....I had to take matters into my own hands. So I "borrowed" six big honker rare earth magnets from work and threw them in my backpack.

There I was at the subdivision traffic light that night trying everything including getting off the bike and dragging my backpack over the acutator lines. Nothing. Then I noticed that three cars were behind me taking all this in and deciding that that lady down the street with the new bike REALLY IS CRAZY.

[bikerHen]

I've got one fairly isolated light that never changes for me and there is rarely traffic to activate it. I usually just wait for cross traffic to clear and go. Last night I rode home after dark and tried shining my helmet light back and forth across the sensor up by the light. It worked!? :D But then again, maybe it was because I was on my steel bike instead of my carbon fiber Ruby. The light did a random change for me the other day (while riding my steel bike). In fact I missed my green light cause that's where I usually stop to take a swig of water and blow my nose. Never looked at the light until I noticed the cross traffic stopping. :rolleyes: bikerHen

[TrekTheKaty]

YOU GUYS ROCK! Who knew? I JUST SENT AN EMAIL TO MoDOT. Not only do we have a light that doesn't trigger for us, if a car triggers it from the left turn lane--it is the shortest light you've ever seen! We can't get across before it changes.

[Becky]

I emailed DelDOT yesterday about a light that doesn't trip for bikes. This is the response that I received:

"However, in regard to setting traffic signals to detect bicycles, we have not historically set signals to detect bicycles. I’ve been told the problem with doing this, is that most bicycles do not have enough metal for the detection to pickup."

Help me write an educated response, ladies! I wanted to ask the guy if he was advocating bicycles running red lights, but decided that wasn't the most politically-correct way to handle it....

*wanders off to find the 2000 DelDOT Bicycle Policy online*

[Biciclista]

you can direct them to this person:


You stated that your steel frame bicycle does not actuate the signal. It may take some information on how to position your bicycle across the sensor, but it should be able to "see" your bicycle. Even if there was a malfunction and you did not get detected, the eastbound and westbound through-traffic movements are quite heavy, and the vehicles that are waiting behind you will actuate the signal when it is your turn to go.

I have sent a request to our crews to double-check the sensitivity of the detection and verify that bicycles are being detected. If they find that they are not, we will address the problem immediately; it is one of our goals to be bicycle-friendly, and that includes having detection that is sensitive enough to serve the commuting bicyclist. If you need information about how to position your bicycle to ensure good detection, all of the local bicycle clubs have this information and are always happy to share.

I hope that I have addressed all of your concerns. If you have any other questions, feel free to contact me directly at (206) 386-4529 or chris.faulkner@seattle.gov.

[Eden]

Becky, that sounds totally bogus to me.... many of our intersections even have a little "T" painted on the optimal place to put your bike to change the signal... and you can contact the DOT if a light won't trigger - they actually do come and re-calibrate the device to pick you up. Even my CF bike has enough metal (rims, spokes, cranks/chainrings on mine) to be "seen" by a properly set up signal.

[Becky]

I'm inclined to agree, Eden... I can't wait to live somewhere bike-friendly.....*sighs*

I found this in the DelDOT Bike Plan: "Support facilities such as parking devices, transport racks on buses, and signal detection for bicycles shall be considered for incorporation into transportation projects during planning and project development. Bicycle friendly drainage grates shall be used to replace parallel bar grates on all roadway reconstruction and rehabilitation projects or replaced individually upon request."

I work for the gub'mint. I know what "shall be considered" means....."we'll toss this idea around and then chuck it out the window, just to say that we considered it." Methinks that I'm out of luck. I intend to email our Pedestrian and Bike Coordinator, just to see what his take is on it.

FWIW, I did find this article about traffic sensors while Googling: http://www.humantransport.org/bicycledriving/library/signals/detection.htm. Very informative!

[Eden]

That's a very cool article!

[bikerHen]

I've been playing with my isolated signal, trying different approaches. Riding up to the stop in the middle of the lane does seem to activate the signal regardless of which bike I'm riding. Which is kinda cool, but on the other hand now I can't stop at the curb to drink and blow my nose. :p bikerHen

[TrekTheKaty]

Here is the response from MoDot:

"Thank you for contacting the Missouri Department of Transportation. The
traffic engineer informed me that, unfortunately, there is nothing we can
do to increase the sensitivity for bicycles. We encourage you to contact
us with any future questions or concerns regarding the maintenance of our
state roads."

[Becky]

Here is the response from MoDot:

"Thank you for contacting the Missouri Department of Transportation. The
traffic engineer informed me that, unfortunately, there is nothing we can
do to increase the sensitivity for bicycles. We encourage you to contact
us with any future questions or concerns regarding the maintenance of our
state roads."

I wonder if Delaware's traffic engineers went to the same school as Missouri's :rolleyes:

[Eden]

You should both forward your respective DOT's the article Becky found!

[OakLeaf]

Trouble is, if it's a magnetic sensor vs. the new optical ones, and you don't have a steel frame, there truly is nothing they can do (short of spending the however many tens of thousands it would be to go to an optical sensor).

When I rode steel, I always found that a hand's breadth to the right of the oil slick would trigger the sensor 9 times out of 10. You don't want to be on the curb in traffic anyway ;)

[Eden]

Trouble is, if it's a magnetic sensor vs. the new optical ones, and you don't have a steel frame, there truly is nothing they can do (short of spending the however many tens of thousands it would be to go to an optical sensor).

When I rode steel, I always found that a hand's breadth to the right of the oil slick would trigger the sensor 9 times out of 10. You don't want to be on the curb in traffic anyway ;)


No traffic sensors *do not work by magnetism* - as the name implies - induction loop sensor, its inductance - like a metal detector, so they can detect many types of metals. In fact if you read the article that Becky posted the sensors should be better at detecting aluminum than steel. The only reason a car is easier to detect than a bike is the size of the vehicle. The sensitivity is adjustable and there seems to be no reason that a good traffic engineer should not be able to set them up to detect bicycles of all types - with perhaps the exception of a person riding a full carbon bike with carbon wheels, spokes and cranks.

I have no problems being detected around here with my carbon bike - I have aluminum rims and spokes. In fact the lights I tend to have trouble with are the optical ones as I am too small to be detected by the camera.....

[TrekTheKaty]

I sent an email back to MoDot and requested more info about the type of signal and received this:

"There are cameras out there which have several zones about half the size of
a vehicle centered in the vehicle lanes. (They should be able to see the
cameras up on the signal mast arm). The front grill on a vehicle is what is
most noticeable to the camera. Cyclists can try turning to increase their
visible surface area, make themselves as "wide" as possible. It may help.
Found this webpage that talks about how to trigger green lights but it
mostly talks about loops. They might find it helpful.

http://www.wikihow.com/Trigger-Green-Traffic-Lights"