Sunday, January 11, 2015

Power & Importance of Research #TRBAM

I blame graduate school and the internet (yes, that was new way back then) for the excitement I have for the research of transportation. I spent a lot of time during my time at Texas A&M and Texas Transportation Institute learning as much as I could on various topics that would help me be an effective engineer and leader in the future.  All of the time in Texas, I was fortunate to have access to not only the internet, but also many of the researchers who had contributed to our knowledge in the industry.

As I think about research, it truly is an essential part of transportation in many ways. The innovation that comes not only from research but by collaboration that happens at the annual TRB meeting results in leads to development and application of new processes and materials for an effectively functioning system. It is through research that the issues as defined by our political leaders and transportation practitioners can be addressed with limited resources.

The USDOT Research Plan says the following: Funding research is an investment that pays off through the application of concepts that are proven, via research, to be effective, resulting in a more efficient, durable, and convenient national transportation system.  

I appreciate that statement and support it's content, but also think that there was a key. Essays of safety missed in the content. Fortunately, safety is a big part of the document an at the front of much of the work that we do.

Comments from Professionals Against Changing the MUTCD

This post was inspired by how complicated it can be to modify a standard sign. The specific sign is shown below and is the Right Turn Yield to Pedestrians Sign.

There was significant debate on a seemingly simple topic of adding a bicycle symbol to a sign that previously had a walking person as the only option.  
There were 40 comments from across the country that included some fairly concerning perspectives that border on unprofessional. One comment that I am willing to talk about includes that by adding a bicycle symbol to the sign, "there is an impact to pedestrian travel". In other words, the simple placement of a bicycle on the sign would somehow degrade the pedestrian environment.

The specific comment was: "The R10-15 sign should only be used at intersections where there are no marked crosswalks, because the sign gives the pedestrians short shrift." Clearly the comment was made in a manner that highlights bias from the commenter. I think this reflects the challenge of people working to improve the bicycling and pedestrian environment.

Another thing that the commenters seem to forget is that the sign is optional. Clearly, if their engineering judgment suggests that the sign is not the right one for their conditions, they don't have to use it. In Portland, we have found them helpful and will continue to use them selectively to address locations where travelers may benefit from a reminder of the expectation.

There was also a comment related to "how will people on bicycle know how to use these signs". Luckily on the Committee, the point was made that the sign is not for the people on bicycles, but rather for oncoming vehicles that could use the information explicitly.

TRB Annual Meeting 2015 papers

I am always proud of the range of work that I can be involved in to advance the profession. The following is the abstract of each paper I had a small part in. I am very lucky to work with such smart people working to improve the transportation industry.

Assessment of Bicyclist Behavior at Traffic Signals with Detector Confirmation Feedback Device - 15-3409
Boudart, Jesse Alexander; Koonce, Peter J .V.
Monday, 07:30 PM - 09:30 PM
Bicycling is increasing in North America and therefore intersections have been modified to better accommodate these new cyclists. However, the increasing demand of cycling is outpacing the supply of high quality cycling markings, signing, signals, and general infrastructure at intersections. For example, recent research indicates more than 50% of bicyclists do not understand that the 9C-7 bicycle stencil symbol indicates the optimal waiting position for a cyclist to call a green light. Subsequently, people on bikes may run red lights because they don’t understand the feedback of a 9C-7 pavement marking. This cycling infrastructure shortcoming illustrates the need to study how new roadway information may impact user behavior and traffic signal compliance. This research documents the impacts of an active feedback device on cyclist behavior in an effort to improve the cycling experience for the increasing number of cyclists. A blue light feedback device was installed at a signalized intersection approach and its impact on bicyclist behavior, indicating that a statistically significant increase of people on bikes used the 9C-7 marking instead of the existing bicycle push button after installation of the blue light feedback device and especially after a sandwich board sign was installed describing the purpose of the blue light. These results indicate a blue light feedback device (accompanied with bicycle detection and the standard marking) could be used effectively in lieu of bicycle push buttons. Also, the impact of the blue light feedback device on bicyclist compliance with traffic signals (red light runners) was negligible.

Exploring Thresholds for Timing Strategies on a Pedestrian Active Corridor - 15-3025
Kothuri, Sirisha Murthy; Koonce, Peter J .V.; Monsere, Christopher M.; Reynolds, Titus 
Traditional signal timing policies have typically prioritized vehicles over pedestrians at intersections, leading to undesirable consequences such as large delays and risky crossing behaviors. The objective of this paper is to explore signal timing control strategies to reduce pedestrian delay at signalized intersections. The impacts of change in signal controller mode of operation (coordinated vs. free) at intersections were studied using the micro-simulation software VISSIM. A base model was developed and calibrated for an existing pedestrian active corridor. The base model of three intersections was used to explore the effects of mode of operation and measures of delay for pedestrians and all users. From a pedestrian perspective, free operation was found to be more beneficial due to lower delays. However, from a system wide (all user) perspective, coordinated operation showed the greatest benefits with lowest system delay under heavy traffic conditions (v/c > 0.7). In the off-peak conditions when traffic volumes are lower, free operation resulted in lowest system delay (v/c < 0.7). During coordination, lower cycle lengths were beneficial for pedestrians, due to smaller delays. The results revealed that volume to capacity (v/c) ratios for the major street volumes coupled with pedestrian actuation frequency for the side street phases, could be used to determine the signal controller mode of operation that produces the lowest system delay. The results were used to create a guidance matrix for controller mode based on pedestrian and vehicle volumes. To demonstrate application, the matrix is applied to another corridor in a case study approach.

 Estimating Performance of Traffic Signals based on Link Travel Times - 15-3371
So, Jaehyun ; Stevanovic, Aleksandar ; Koonce, Peter J .V.
Tuesday, 07:30 PM - 09:30
Recent advances in communication and computing technologies made travel time measurements available more than ever before. On urban signalized arterials, travel times are strongly influenced by traffic signals. Yet, these travel times are rarely used to deduce information about performance of the signals. This study presents a novel method, based on well-known principles, to estimate performance of traffic signals (or more precisely their major through movements) based on travel time measurements. The travel times are collected between signals in the field, by using one of the point-to-point travel time measurement technologies. Closed-circuit television cameras and signal databases are used to collect traffic demand and signal timings, respectively. Then, Volume/Capacity ratio of major movement of the downstream signal is computed based on the demand and signal timings. This Volume/Capacity ratio is then correlated with the travel times on the relevant intersection approach. The best volume-delay function is found, among many, to fit the field data. This volume-delay function is then used to estimate Volume/Capacity ratios and, indirectly, few other signal performance metrics. The method, called Travel Time based Signal Performance Measurements, is automated and displayed on a Google Map. The findings show that the proposed method is accurate and robust enough to provide necessary information about signal performance. A newly developed volume-delay function is found to work just slightly better than the Bureau of Public Roads curve. Several issues, which may reduce the accuracy of the proposed method, are identified and their fixes are proposed in future research.

G06 - Does the Bicycle Detector Symbol Change Cyclist Queuing Position at Signalized Intersections? - 15-2501
Bussey, Stefan W; Monsere, Christopher M.; Koonce, Peter J .V.
Tuesday, 10:45 AM - 12:30 PM
The Manual of Traffic Control Devices (MUTCD) includes a bicycle detector pavement marking (Section 9C-05) and accompanying explanatory sign (R10-22) which may encourage cyclists to position themselves over detection at traffic signals. This paper presents the results of an observational and survey-based study evaluating the bicycle detector marking. Three minor actuated approaches at signalized intersections with significant bicycle volumes and without bicycle detector markings were selected for treatment. Three configurations were compared: 1) bicycle detector marking only 2) bicycle detector marking with the R10-22 explanatory sign, and 3) an alternative bicycle detector installed over a contrasting green rectangle. Analysis of 688 observations, gleaned from over 300 hours of before and after video data, indicate that while all three marking options influence cyclist stopping position, the effect of the marking is not large. For the marking only, 23.5% of cyclists waited over the space where the marking was installed. This improves to 34.8% with the addition of the explanatory sign and 48.4% when the marking is applied over the green rectangle. Analysis of survey responses of 227 cyclists indicates that only 45.4% of cyclists understand the roadway marking is meant to show where they should wait to be detected. An additional 11.5% understand that the marking indicates the recommended waiting location, but do not know that it is for the purpose of detection. Finally, survey respondents expressed concern about waiting in the travel lane and preference to wait closer to the curb (a position which usually prevents them detected).

Friday, January 9, 2015

NCUTCD Bicycle Technical Committee Reviews Two Stage Queue Box

The first day of meetings of the National Committee on Uniform Traffic Control Devices Committee started off in the afternoon with a discussion about the comments that were received on new sections proposed for a future Manual of Uniform Traffic Control Devices (scheduled now for 2017). This effort is part of the review to vet the materials that are new to the MUTCD. 

It's worth describing some of the practices of the Committee and to critique how it might be better. A criticism to make the time more productive is to invite presentations of research to address the comments and to inform the Technical Committee. Presentation of research prior to the conversation to the members would increase the expertise around the table. 

Most of what goes into the Manual in the Bicycle Section is based on the best information available from the people around the table at the meeting. What NACTO was able to do was to gather information from engaged stakeholders without requiring specific travel to finish the document. A face to face review of the materials would have made it better, but if you have people engaged in the process and it is participatory, it can be very powerful (Wikipedia comes to mind as a pretty darn successful model).  At the NCUTCD there is a certain amount of discussion around the table of whether the participants know of new treatments and whether they have "worked" or not.  Portland is often cited as an example where these new treatments has been applied and there are times when the professionals in the room are not familiar with the information other than having the comments and the original discussion about how they have been written for the Chapter and some limited knowledge of how these treatments have been applied.  

There was some criticism of NACTO in that there isn't a full vetting process of some of the treatments in their documents, i.e. the general public has not had a chance to comment. The reality of the work in the Urban Bikeway Design Guide is that is that is a collection of work and practices implemented in major cities that are not represented on the National Committee of Uniform Traffic Control Devices and since it is not a standard, it's a collection of practices. NACTO uses the MUTCD concepts of options, "standards", etc.  The examples below are not uniform, but the pieces are largely similar. Uniformity at lower speeds is less necessary in my perspective and a discussion of the potential to confuse motorists has not been demonstrated in research. 

Examples of Two Stage Queue Boxes (NACTO City submissions)

In summary, the NACTO Urban Bikeway Design Guide highlights specific treatments and examples that provide information about how two stage queue boxes have been applied. Submissions by City staff involved in NACTO although not fully vetted through research, is informed by practice. A professional could argue that City staff are as knowledgeable about the effectiveness of their treatments as researchers that study the treatments for a few days in a more comprehensive way at sites in order to get a statistically valid sample. Yet, there are criticisms of that approach as well and while the NACTO guidance is not vetted in the classic research sense, the authors are familiar with the applications and the practical experience is used to adjust the treatments to make them effective based on customer complaints. 

One of the other challenges of the NCUTCD group is that the technical committees meet separately so the entire Signals Committee rarely talks to the Bicycle Technical Committee nor the Roadway Markings Committee, etc. If the National Committee is to continue to be the national experts on traffic control devices, the group has to do a better job of: getting research presented as a part of the consideration of new devices, exploring treatments that are being implemented in the field, cross training NCUTCD members on context sensitive design, and advocate for increased funding for research that identifies innovative techniques to move people safely in urban areas.