Bike Signals Presentation at 2012 #TRBAM

The CROW Manual is a great
resource for bicycle design.

Putting the finishing touches on the Bike Signals presentation and it is helpful to refocus some of the efforts for the coming months and years. Reflection on something as simple as a bike signal shows not only how far we have come, but also how much we have to do to make cycling safe in Portland.  
There are a wide variety of elements that we have used on the nine bicycle signals that we have built. The map that I have been using to inventory the system and planned indications is helpful to keep straight all of the work that is in the works.
View Portland's Bicycle Signals in a larger map

The NACTO Bike Guide presentations were very good overall. I learned quite a few things and did a bit of binge tweeting with nine tweets in about 4 hours.

Preparation for my presentation caused me to review the Guide in more depth and I found a few things that I disagree with in the signals portion, most notably the Clearance interval issue, which is something that's an ongoing debate at the Institute of Transportation Engineers and National Cooperative Highway Research Program efforts that have been worked on by VHB and Wayne State University. It's a project that originally proposed an arbitrary increase in yellow time for all cases where people on bicycles are present. All in the name of safety. I contend (consistent with the research) that the longer you make a clearance interval the more people will learn the constraints of the system and they will make decisions based on the known risk factors. The higher the clearance interval (yellow and all red) the higher likelihood for variable behavior. Higher speeds contribute to this issue and it falls back to the fundamental concept for how speeds are set in the U.S.