Sunday, January 11, 2015

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).

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