traffic signal actuators

[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/bicycl.../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. 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

[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"