Friday, March 22, 2013

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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Friday, March 8, 2013

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 
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. 

Thursday, March 7, 2013

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).
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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.      
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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. 
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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.

Safety Treatments for Pedestrian Crossings - Crosswalks, Rapid Flash Beacons, and HAWKs

Research on crosswalk markings and their detection

The Federal Highway Administration research panel meeting for this project was held in College Station, Texas and it was a great opportunity to view the test course that was used to discuss the effectiveness of safety treatments for pedestrian crossings. There is a wide variety of treatments that we can use and there is a need for guidance on when the treatments are appropriate. There is a lot of bias in these guidelines and challenges with their use.

The first part of the research is for crosswalk markings and they tested three different types of crosswalk markings on different streets and speed limits. The research showed that the continental crosswalk markings are detected at a further distance than transverse markings. One of the questions that wasn't answered is how the marking types are affected by limited maintenance practices, which are common in these resource constrained times. In Portland's case there a blog devoted to the crosswalks that have been neglected. One of the considerations I asked for is to determine the long-term changes associated with these different maintenance practices and how transverse markings look more like continental over time.  

The other study was for the effectiveness of the rapid flash beacons and the size of their display. The study on the test course was the rapid flash beacon and the testing of the various configurations and shapes.

Setup of the circular rapid flash beacon on the test course.

The night time setup of the rapid flash beacon. Distance from 150' shows how hard
it is to identify pedestrians near the sign without street lighting. 
I can't disclose information from the research on the rapid flashing beacons because it is still underway.  

The testing on the test course had several limitations, but offered a great first attempt to identify the issues associated with their application. The nighttime observations were very interesting and offered some very interesting results. 

One of the great things about working on this panel is the collaboration with the agencies that are involved and seeing what others are doing. The City of Portland has done several things to modify their treatments at intersections to time the vehicle signals on the pedestrian hybrid beacons so that the safety of pedestrians is paramount. The difference is that we wait to allow the flashing red (for main street vehicle traffic). That choice is not currently allowed in the MUTCD. Apparently, the new edition of the Manual will allow what we do. I learned on this trip that D.C. has also lengthened the solid red on their pedestrian countdown which is consistent with the National Association of City Transportation Officials Pedestrian Hybrid Beacons version of this with the exception that they don't use the bike signal in DC.

Tuesday, March 5, 2013

Everyday Maintenance - Telling the Story

I work with professionals that repair the infrastructure that gets damaged from people travelling within and through the City every day. It is easy to overlook this work because often we're responding within hours of a crash to make the street or sidewalk safe for everyone that comes across the incident. 
As an engineer, I never learned much about maintenance. Calculations about how you deal with equipment that has been damaged are difficult (messy), we can't make a lot of assumptions that we can count on. We're trained to work on projects where we start fresh and you have a blank slate. That's not possible with the real world day to day maintenance, so we do what we can with what is available in some cases. 
The repair that these professionals in the field make are impressive when you think about the wide variety of things they come across. Here's just one example. 

This particular example is from September 2012 at NW Broadway at Davis.

We don't have this type of ornamental poles at the ready, so we had to take a few days to order the pole and replace it the following week. The challenge with this ornamental pole is that the rods that are part of the foundation are over sixty years old (some of them are from the 1920s). Not exactly your perfect world engineering calculation. 

Monday, March 4, 2013

Bike Signals State of the Practice

North American cities have been making huge leaps in creating safe places to bike in recent years. The National Association of City Transportation Officials (NACTO) recently published the Urban Bikeway Design Guide to describe the best practices that can be used to improve conditions for cycling and includes a section on bicycle-specific signals. Bicycle-specific traffic signals are used at intersections with conventional signals to specifically control cyclists’ movement and were recently reported on by USA Today. Though use of bicycle-specific signals are limited by the US Manual on Uniform Traffic Control Devices (MUTCD) there is still considerable experience with bicycle-specific signals in North America.
The morning rush on the Broadway Bridge in Portland, OR. Signals controlling motor vehicles, bicycles and streetcar keep orderly flow. The photo inset shows the detail of the bicycle signal head. Photo P. Koonce

In a soon to be published paper in the TRB’s Transportation Research Record, researchers at Portland State University—in collaboration with engineers from the Portland Bureau of Transportation and the Oregon Department of Transportation—summarize the results of a recent state-of-the-practice review related to bicycle-specific signals. The review included two components: 1) a review of related engineering guidance documents:

·         Manual on Uniform Traffic Control Devices (MUTCD) (FHWA, 2009)
·         Traffic Signal Guidelines for Bicycles (Transportation Association of Canada (TAC), 2004)
·         Manual of Uniform Traffic Control Devices for Canada, 2008 update (TAC, 2008)
·         Design Manual for Bicycle Traffic (CROW, 2007)

and 2) a survey sent to jurisdictions with known bicycle-specific signals.  Survey responses were received from 15 of the 21 jurisdictions, representing 63 intersections which contained a total of 149 separate bicycle-specific signal heads. Jurisdictions included in the survey are shown as black boxes within the figure:

Jurisdictions identified with bicycle-specific signals and survey respondents. Note numbers following the “:” denote the number of reported signal heads at that location, jurisdictions with a ‘U’ value did not respond to the survey.

The paper summarizes both physical and operational design guidance. Physical elements reviewed include details about the suggested size of lens, the use of bicycle insignia within the lens, color and presence of backplates, and placement of the signal head. The review of the operational elements include details about the bicycle-specific signal’s detection, phasing, restricted movements for other modes, accompanying signage, and intervals for cyclists to safely cross the intersection. Overall, while there were minor differences between the guidance documents, the guidance was generally consistent.

This survey requested detailed engineering aspects about each jurisdiction’s bicycle-specific signal that they were operating, the topics of which were previously mentioned (placement, mounting height, lens diameter, backplate and housing color, type of actuation, interval times, use of louvers, and performance). The survey of practice found a variety of design elements: lens size, use of insignia, utilization of louvers, mounting location, and the means to designate that the signal head is for bicyclists. These elements could have significant impact on bicyclist and motorist comprehension, as well as the ability to utilize the bicycle signal head in a variety of intersection configurations. Some consensus appears on the use of the lens insignia and accompanying signage. Another part of the survey asked for motivating reasons as to why the jurisdiction had decided to install a bicycle-specific signal at each respective intersection, allowing multiple reasons to be cited. Responses were grouped into five categories: ‘cyclist non-compliance with previous traffic control’, ‘presence of a contra-flow bicycle movement’, ‘a diagonal (or otherwise unique) cyclist path through the intersection’, ‘safety concerns for cyclists’, and ‘other’. The survey responses indicated that bicycle signals are most commonly installed when cyclists are moving against motor vehicle movements, taking a non-standard path through an intersection, or when there are safety concerns for cyclists at that intersection. Many signals in Vancouver, BC and Montreal, QC are used to control contra-flow movements on two-way cycle tracks.

Bicycle-specific traffic signals are common in many places throughout Europe, however, they are a new tool for transportation engineers in North America. The availability of engineering guidance has improved substantially over the past few years with the release of the California MUTCD, NACTO’s Urban Bikeway Design Guide, and AASHTO’s guidance. While there are minor differences, there is generally consistent guidance. To some extent, the guidance documents reflect the lessons learned by the surveyed jurisdictions since installation of the bicycle-specific signals is limited to those places willing to experiment. The survey of practice found a variety in some design elements: lens size, use of insignia, utilization of louvers, mounting location, and the means to designate that the signal head is for bicyclists. Some consensus appears on the use of the lens insignia and accompanying signage. Given the accelerated deployments of bicycle-specific signals and the new guidance documents, it is likely that there will be less variety in future designs. Adoption of minimum guidance in the U.S. MUTCD would also likely improve consistency and practice. The National Committee on Uniform Traffic Control Devices is presently considering language addressing bicycle-specific signals.

Saturday, March 2, 2013

SW Broadway Bike Lane

  I was so surprised to see SW Broadway carrying 16 people on bicycles during a single cycle this past week (it was February and pretty cold) that I tweeted a picture that was picked up by and he made the case that the street needs a better bikeway. Here's a shot from the 2008 Tour de Fat parade that has SW Broadway with a critical mass of riders on a Sunday morning enjoying the warm August morning trip from the Waterfront to the Pearl District and back again. New Belgium Brewing knows how to throw a fun summer party, it would be great if a local brewer would take on this sort of model to raise money for the Bicycle Transportation Alliance!
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