View Full Version : How do you get change?

11-18-2008, 11:37 AM
Traffic signal heading north on 29th at nw29th and Nicolai is a 5 second green. This is coming off a dead end road that has a cut through for bikes. This is on a route that anyone who works at Chris King might take on a commute. I ride it daily myself. THe problem is trucks and buses that use this route are heading south and turning left to go up towards NW Vaughn and NW 23rd part of town. They know the light only lasts 5 seconds so they don't like to wait for bikes going straight. They start the turn before I clear the intersection and this makes me very nervous. I don't blame them, the light is to short. So seems solution is simple. How and who do I approach to get this changed. BTA, City of Portland or just wait until someone gets hit? I realize nothing is simple and a lengthy review process will be required... but I am not exaggerating this is a 5 SECOND LIGHT!!!! Any help/suggestion is appreciated.

11-19-2008, 10:16 AM
B-c, sounds like it's a fairly simple signal timing issue, something the City's Signals folks have the ability to adjust as needed. If you can accurately describe the problem to them, they'll either fix it or give you a reason why they can't or won't.

Your person to contact is:

District: NW - except Pearl/River District
Tod Rosinbum

Also, calling 823-SAFE would be an alternate route, albeit somewhat slower.

11-19-2008, 04:24 PM
Thanks for the info. I will e-mail PDOT and see what happens.

11-20-2008, 01:23 PM
b-c, by all means, report back on results, or lack thereof.

11-20-2008, 03:31 PM
E-mailed Tod as you suggested and copied BTA and Chris King Precision parts (Chris King is located within a mile of this intersection). I thought it couldn't hurt to try to get some support from others with more clout than I.

01-11-2009, 07:44 AM
No change since October... i have heard no response. Any further suggestions?

01-14-2009, 10:28 AM
I'll e-mail this thread to Tod. That may help.

01-17-2009, 08:10 AM
b-c, here's what i got yesterday in an email from Nelson Chi, a City signals technician:

"I checked the signal operation and determined that longer green is needed for 29th Ave to accommodate the bike. The timing is adjusted and should work better now. Additionally, we were going to install an overhead sign "LEFT TURN YIELD TO ONCOMING TRAFFIC" for the southbound NW 29th Ave approach as result of traffic investigation. "

check it out. I don't know what happened to your original request, seems like they might have lost it somehow..?

01-17-2009, 10:56 AM
My commute takes me down NW Wardway St on to NW Nicolai St around 5:45 to 6:00 in the morning. Traffic ranges for non-existent to waves of 3-6 autos.

Google map of area for reference (http://tinyurl.com/9j9fum)

Before the recent change the green light would cycle from southbound 29th to northbound 29th(only when triggered) to east bound Nicolai St and finally Wardway St.

Within the last two weeks the northbound 29th signal always comes on whether there is traffic to trigger it or not. It also seem to last longer, though all it does is increase my wait at the Wardway light.

01-24-2009, 07:44 AM
I have been bike commuting this route for over a year and never observed a separate North bound South bound light cycle on 29th. It always has turned both north and south 29th light at the same time. Thus the stated danger of the short light cycle, since most vehicles are turning here and short light did not allow everyone ample time to yield and still make the light. While the 29th loops to trigger the light work most of the time there are times when I have sat through several cycles waiting my turn (the latest just yesterday). The signal light cycle for 29th does appear to have lengthened, but the loop still seems to need a bike or vehicle to trigger the loop. I have recently observed it not changing when no one is on the loop, there is no need to cycle 29th signal when no traffic is present unless the loop fails to trigger which in my experience is the rare exception. As for the additional 3 to 5 seconds added to the 29th av light I hope this small improvement in safety does not lengthen

01-24-2009, 07:53 AM
does not lengthen your commute to much, but it does improve safety greatly for those that take 29th. While I do ride in traffic when I must I readily avoid NW Wardway by taking Raleigh to 28th to Upshur to 29th. This makes for safer option that does not add significantly to my commute time.

01-24-2009, 08:01 AM
Bikieboy, Thank you so much for the change! and also thanks to PDOT for taking the time to check into it. I am still a bit puzzled on why I received no response from my original e-mail. Do you have connections in city hall? I am still unclear on how to get change, since what I tried did not work without your help. Anyway, if the opportunity arises I owe you a cup of coffee, or a beer. Thanks again, Bobcycle

01-24-2009, 12:27 PM
Let me start by acknowledging that wire loops are a real PITA. It's especially annoying in Washington County, where the engineers are more interested in avoiding false signals (thus slowing down cross traffic) than they are in allowing legitimate road users to safely share the road; they routinely set the sensitivity to be markedly less than the nationally recommended standard. :mad:

That being said, I have found that 95% of these wire loops can be triggered, if you understand their principles of operation and apply those principles properly.

First of all, the wire loops use induction, not magnetism, in order to sense your presence. Induction is like when you put your hand on a cheap AM radio and the reception improves. Anything that conducts electricity, including titanium, magnesium, aluminum, or salt water (which is what you are mostly made of) have inductive properties. (These little magnets you're supposed to buy and put on your bottom bracket are pure snake oil!) The traffic light control recognizes when inductance on the sensor exceeds some cumulative threshold.

Second, the sensors are designed to not change the light if the inductance threshold is triggered only momentarily. Thus, the steps that one takes to exceed the inductive threshold must be maintained until the light changes. Stay put! Don't try to trigger the light and then move forward or to the right afterwards.

Third, these wire loops are most sensitive near the wire itself. The sensor triggers when the total inductance exceeds some threshold that is specifically tuned by the field engineer.

So, here's what I do. First of all, suppose it's a diamond shaped sensor; you've got four quadrants (upper left, lower left, upper right, and lower right). In this case, I stop over the sensor with my entire front wheel exactly over and parallel to the upper left quadrant. The rear wheel intersects the low left quadrant, and my left foot crosses both the upper left and lower left quadrants at the corner where I'm standing. I then hold the position until the light turns.

One could also mirror this right-side with a right-footed stop. However, I usually feel safer on the left side since I'm further out in the intersection and controlling the lane.

The round sensors are much harder to trigger. I know, it's not supposed to be that way, but there it is :mad:. I angle my front wheel to the right (like before), positioned so that it touches the pavement slightly inside of the circle and crosses the circle both in front of and behind the contact point. In geometric terms, I want the wheel to trace a "chord" that passes as close to the wire as possible. My rear wheel I try to position so the point of contact is directly on the wire loop. I then place my left foot directly on the wire loop at my left.

Like I said, this almost always works. There's only one complication that you should be aware of: rain. If the pavement over the wire loop is very wet (like in a heavy rain), the wire loop's sensitivity is further reduced. When you think you've mastered the wire loops on your route, a day will come when you have to trigger the light while standing in a real toad strangler. Just be forewarned: just when you realize you're getting really wet and cold, you'll just have to take your life into your hands and run the light. (Case in point is eastbound Butner Road at Cedar Hills Boulevard. Don't go there, Dorothy; it works just fine if it's dry or just damp....)

Finally, at least here in Washington County, the authorities are generally receptive to adjusting lights that won't change for bicyclists. They just don't tune them correctly to begin with. Just last week I saw a traffic engineer adjusting the left turn lane from northbound Murray Road onto Cornell Road. He sat at the control box and waved a full size pickup back and forth as he calibrated the sensor. "You pinhead!" I wanted to scream at him, "you should have a 100 pound middle schooler on a 30 pound mountain bike out there instead of a pickup truck!"

But now I'm just getting grumpy. Seriously, you'll find that most wire loops are perfectly tractable if you treat them property. Be safe!