Week in Review - Mid-March 2013

I took a few pictures throughout the week that I thought were worth sharing. These are random collections of various things that catch my attention and obviously are different projects that are going on or that cross my desk.   

The latest cover of the ITE Journal had Rock Miller's influence

Pavement marking for the Ronde PDX Ride

A pedestrian signal head adjacent to the Sellwood Bridge was knocked off alignment, so I emailed staff at Maintenance

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Half Signals & HAWKs or Pedestrian Hybrid Beacons

At the meeting with the Texas Transportation Institute and the Federal Highway Administration and I learned today that the difference between Half Signals and Pedestrian Hybrid beacons is not statistically significant. I came across this chart that I found with a quick google search.

Slide from a presentation from the Baltimore Metropolitan Council
Exact source: unknown

This is a little bit different than the NCHRP 3-71 study that was published in the document as NCHRP 562.

Transportation Performance Measures

I posted this to the ITE Listserv this morning:

The Portland Metropolitan area has been working on creating arterial performance measures by using data from our traffic signals and other sources (Bluetooth, transit AVL, etc) to monitor the transportation system performance. We're interested in learning from others on their experiences of producing arterial performance measures.

Transit AVL data
Bluetooth data
All Data from an Arterial (Data Capture from a variety of sources on a corridor) 

We have also used a limited amount of adaptive control and are familiar with the performance measures of some of those systems. 
 
1. What are the best ways to integrate these data sources? 
2. What is the tradeoff between the number of MAC and other roadside readers and performance measure 
accuracy? 
3. How can bus transit and traffic signal data be integrated to improve arterial performance measures?

I am hoping to hear from practitioners that have implemented systems and how they have used their traffic signal system to produce some of these measures. This might also help us in preparing our Summer meeting workshop for the Transportation Research Board Committee on Traffic Signal Systems which is coming to Portland in July. 

Historic Traffic Signal from So. Cal

      I tweeted this photo as an example of the bias the traffic industry has had. Interesting that the "Auto Club of South California" has their name on this sign that is part of the traffic signal.   The traffic signal dates from some of the earliest on record (likely in the 1920s) and the LADOT website has a nice summary of some of the work that was done in L.A. along with some of their innovations, including the first pedestrian actuated signal (which increased delay for pedestrians).

Historic Waterhouse Traffic Signal

This traffic signal was found in the Texas Transportation Institute's lobby and is a Waterhouse Traffic Signal that was in the City of Los Angeles in the 1930s.

The traffic signal has the Go indication that rotates in and out.

The industry has quite a lot of discussion about clearance intervals these days and the historic traffic signals are a great opportunities to look at what has worked. This indication did not have a yellow and show red directly from green. Thus, you're supposed to stop as soon as it changes and leave it to the next movement to determine when it is safe to enter the intersection.      

Rapid Flash Beacon Laboratory Study

    At the Texas Transportation Institute office buildings, they have a great setup for measuring the brightness of the devices or legibility of a sign and its font. The researchers here gave us some great insights into the work they are doing. With some very simple demonstrations, they showed us how we fail to evaluate things scientifically in many cases and their effects on the distance where the beacon is at its greatest intensity.
The example from this day was the importance of angle for the rapid flashing beacon on the percieved intensity. In the example, they modified the angle where the beacons were pointed by 5 degrees and it was pretty suprising what the differences were. It was also surprising how different vertical angles were and again, it made me wonder what guidance we are providing to our electrical staff to insure that the settings are within reason. It's another good example where the intent of the traffic control device needs to be confirmed by being OUT standing in the field.
The second example was the intensity of the rapid flashing beacon and measuring the intensity of the unit by measuring with an oscilliscope and understanding how the pattern of the device is affecting the perspective. It is also something that we needed to use to understand what the effect was on the people who may have epileptic episodes. One of the important issues that remain was to determine what the effect of multiple beacons was on the percieved flashing pattern. If you have three different beacons, how will that be percieved by those that are approaching the beacon? Is an overhead beacon needed? If so, is it rectangular or a circular device?
There are endless questions for this particular study and our intent was to narrow the focus of the effort to those elements that would be most valuable to the profession. I tried to emphasize the practical nature of the research problem statement. Obviously, there are neat things you can do with tools like the ones shown, but if we're not solving an existing problems, are we making the best use of the resources available? That is one of the areas where the Texas Transportation Institute research team seems to excel is that they are listening closely to the practitioners. Hopefully, they will see through the bias of each individual and make decisions that move multimodal transportation solutions forward that seek to balance the priorities of the community. Uniform traffic control devices are a noble goal, but local needs must be considered as well and the recognition that different communities will have priorities that yield differnet answers. 

Austin's Cycletrack on Rio Grande

Traffic signal just for the southbound
movement for people on bicycles.

Visiting Austin, I found they have done a lot of work to improve their cycling network and are exploring cycletracks with a significant amount of emphasis and bolstered by the Green Lane Project.  I enjoyed my time in the City meeting with my peers and found their implementation of cycletracks on Rio Grande to be inspirational.

The Rio Grande cycletrack starts with a bicycle signal (exclusive movement) to transition from the 2-way facility to a more traditional in street environment south of the traffic signal. They have employed the blue light sign for "vehicle detected when blue light on" giving people on bikes a clue that there is something different here and that we want to let you know that you have been detected. The "Bicycle Signal" sign seems to define the indication as it is exclusive for bicycle traffic. I wonder if it was intentional to define that the bicycle was a vehicle through the two separate signs.

The installation is very important in that it allows a crossing that is long through the intersection. It addresses a skewed crossing that without such at treatment would have been a significant barrier to making the movement on your bike. The City has been focusing on eliminating these sorts of spots of bicycle stress in their system. The study by Furth suggested a set of criteria based on Dutch bikeway design criteria for levels of traffic stress (LTS). LTS 1 is suitable for children; LTS 2 represents the traffic stress that most adults will tolerate; LTS 3 and 4 represent greater levels of stress. I am not sure that the signal and geometric design of the intersection results in a level of stress of #1 because it is such as large crossing.

North of the intersection with Martin Luther King Jr. Blvd and the traffic signal, the treatment is a 2-way cycletrack on the eastside of the street. The City removed on-street parking and the street is a one-way street in the northbound direction, so the southbound person on a bike is adjacent to the curb and the northbound movement is a left hand side bicycle lane. The City has taken care to have treatments at intersections, providing stop signs for vehicles and yield signs for mitigating bicycle/pedestrian conflicts.

After conditions on Rio Grande/23rd

Before conditions on Rio Grande/23rd

I surveyed the after condition and went back to google maps for the before conditions. There is construction on the east side of the street associated with some housing that is being built for the university. The traffic volumes along the corridor did not need the multiple lanes, so this example is similar to N Williams in Portland. It is interesting to think about the possibilities of the corridor and what they have done here. It's a great example of the Green Lane Project.
The visit to the corridor showed a lot of pedestrian environment and significant retail activity on the corridor. I didn't have time to explore the other potential southbound routes to determine whether the 2-way cycletrack was necessary, but I like the facility more than I thought I would and reminds me of some of the examples I experienced in the Netherlands.
The staff I met with in Austin seemed energized by the mission, excited about the NACTO Bikeway Guide (it was brought to our meeting), and interested to learn about what Portland has done with traffic signals to improve conditions for cycling.