Reliability Analysis of Minimum Pedestrian Green Interval for Traffic Signals
Publication: Journal of Transportation Engineering
Volume 139, Issue 7
Abstract
The current method of computing the minimum pedestrian green interval for intersection signal timing assumes that the component variables are deterministic. This paper presents a probabilistic method in which the pedestrian start-up time and walking speed are random variables. To establish pedestrian characteristics, data were collected at 14 intersections in downtown, suburban, and tourist areas. The method is based on a safety margin that is defined as the difference between the supplied and demanded green intervals, where the demanded green interval is a random variable. Relationships for the mean and standard deviation of the safety margin of the demanded green interval are developed on the basis of the first-order second-moment analysis. A closed-form solution for the minimum supplied green interval is then derived as a function of the relevant variables, including the vehicular intergreen interval and its component variables. A procedure for establishing the walk and the flashing “don’t walk” intervals is presented. Graphical aids for determining the minimum pedestrian green interval were developed, and application of the proposed method is illustrated using numerical examples. The sensitivity analysis shows that the minimum pedestrian green interval is much more sensitive to the walking speed than the start-up time or their correlation.
Get full access to this article
View all available purchase options and get full access to this article.
Acknowledgments
The authors are grateful to two anonymous reviewers for their thorough and most helpful comments that have motivated some ideas presented in the paper. This research is financially supported by a discovery grant from the Natural Sciences and Engineering Research Council of Canada. The assistance of the following individuals in the data-collection process is acknowledged: Young-Ji Byon, Rana Salah, Udai Hessien (Toronto); and Yang Yang, Di Yang, and Chun Xu (Nanjing).
References
Alhajyaseen, W. K., and Nakamura, N. (2010). “Estimating the minimum required width of signalized crosswalks considering bi-directional pedestrian flow and different age groups.” Asian Transp. Stud., 1(2), 181–198.
Ang, A. H., and Tang, W. H. (1975). Probability concepts in engineering planning and design, Wiley, New York.
Coffin, A., and Morrall, J. (1995). “Walking speeds of elderly pedestrians at crosswalks.”, Transportation Research Board, Washington, DC, 63–67.
Easa, S. M. (1993). “Reliability-based design of intergreen interval at traffic signals.” J. Transp. Eng., 119(2), 255–271.
Federal Highway Administration (FHWA). (2009). Manual on uniform traffic control devices for streets and highways, U.S. Dept. of Transportation, Washington, DC.
Fitzpatrick, K., Turner, S., and Brewer, B. (2007). “Improving pedestrian safety at unsignalized roadway crossings.” ITE J., 77(5), 34–41.
Golani, A., and Damti, H. (2007). “Model for estimating crossing times at high occupancy crosswalks.” Compendium of Papers, 86th Annual Meeting of the Transportation Research Board (CD-ROM), Transportation Research Board, Washington, DC.
Guerrier, J. H., and Jolibois, S. C., Jr. (1998). “The safety of elderly pedestrians at five urban intersections in Miami.” Proc., Human Factors and Ergonomics Society, 42nd Annual Meeting, Human Factors and Ergonomics Society, Santa Monica, California, 171–177.
Haukaas, T. (2011). Mean-value first-order second-moment method (MVFOSM), 〈http://www.inrisk.ubc.ca/process.php?file=probabilistic_methods/mvFOSM.pdf〉 (Jul. 30, 2011).
Knoblauch, R. L., Pietrucha, M. T., and Nitzburg, M. (1995). “Field studies of pedestrian walking speed and startup time.”, Transportation Research Board, Washington, DC, 27–38.
Lam, W. H., and Cheung, C. (2000). “Pedestrian speed/flow relationships for walking facilities in Hong Kong.” J. Transp. Eng., 126(4), 343–349.
Langlois, J. A., Keyl, P. M., Guralnik, J. M., Foley, D. J., Marottoli, R. A., and Wallace, R. B. (1997). “Characteristics of older pedestrians who have difficulty crossing the street.” Am. J. Public Health, 87(3), 393–397.
LaPlante, J., and Kaeser, T. P. (2004). “The continuing evolution of pedestrian walking speed assumptions.” ITE J., 74(9), 32–40.
LaPlante, J., and Kaeser, T. P. (2007). “A history of pedestrian signal walking speed assumptions.” Proc., 3rd Urban Street Symp., Transportation Research Board, Washington, DC.
Milazzo, J. S., Rouphail, N. M., Hummer, J. E., and Allen, D. P. (1999). “Quality of service for interrupted-flow pedestrian facilities.”, Washington, DC, 25–31.
Smith, G. N. (1986). Probability and statistics in civil engineering, Nichols, New York.
TranSafety. (1997). “Researchers study the walking speeds of older pedestrians.” Road Manage. Eng. J., 〈http://www.usroads.com/journals/rej/9704/re970404.htm〉 (Jan. 23, 2012).
Transportation Research Board (TRB). (2000). TRB Special Rep. 209: Highway Capacity Manual, 3rd Ed., Washington, DC.
Zegeer, C., Seiderman, C., Lagerwey, P., Cynecki, M., Ronkin, M., and Schneider, R. (2002). “Pedestrian facilities users guide: Providing safety and mobility.”, Federal Highway Administration, U.S. Dept. of Transportation, Washington, DC.
Information & Authors
Information
Published In
Copyright
© 2013 American Society of Civil Engineers.
History
Received: Feb 3, 2012
Accepted: Feb 11, 2013
Published online: Feb 13, 2013
Published in print: Jul 1, 2013
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.