Assessing the Transferability of the Highway Safety Manual Predictive Method for Urban Roads in Fortaleza City, Brazil
Publication: Journal of Transportation Engineering
Volume 141, Issue 1
Abstract
AASHTO’s Highway Safety Manual (HSM) provides guidance to safety professionals and is becoming a standard of practice, particularly for regions that require urgent action because of persistently high crash frequencies that have resulted from an overall lack of safety investments. Differences in crash data systems, local enforcement, driving behavior, and other factors have prompted studies assessing the international transferability of the HSM predictive method. The recent increase in crash occurrences in Brazilian urban areas and the World Health Organization (WHO) Decade of Action for Road Safety initiative have motivated a nationwide joint safety research effort. One of the fundamental questions in this project is related to the applicability of HSM safety performance functions (SPFs) for the Brazilian urban environment. This paper presents the initial results regarding the transferability of the HSM SPFs for estimating the expected average crash frequency of urban intersections in Fortaleza City, Brazil. The procedure consists of two major steps: the first step investigates the estimation of the calibration factor according the procedure outlined in the HSM and is followed by a model validation effort using a different data sample; the second step is comprised of an analysis of the overdispersion parameter , either using the original estimates from the HSM or recalibrated estimates using local conditions. The results suggest that for the Fortaleza case, the calibrated HSM baseline SPFs can be used with caution. It is, however, worthwhile to analyze the effect of the calibration sample size on the model stability, and efforts to produce SPFs using local data must be considered.
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Acknowledgments
The authors would like to acknowledge the Brazilian Council for Scientific and Technological Development (CNPq) for funding this research.
References
AASHTO. (2010). Highway safety manual, Washington, DC.
Chen, Y., Persaud, B., and Sacchi, E. (2012). “Improving transferability of safety performance functions by Bayesian model averaging.”, Transportation Research Board, Washington, DC, 162–172.
Davis, G. (2004). “Possible aggregation biases in road safety research and a mechanism approach to accident modeling.” Accid. Anal. Prev., 36(6), 1119–1127.
Ferraz, C., Raia-Jr, A., Bezerra, B., Bastos, T., and Rodrigues, C. (2012). Road safety, NEST/USP, São Paulo, Brazil.
Ferreira, S., and Couto, A. (2013). “Traffic flow-accidents relationship for urban intersections on the basis of the translog function.” Saf. Sci., 60, 115–122.
Fridstrom, L., Ifver, J., Ingebrigtsen, S., Kulmala, R., and Thomsen, L. K. (1995). “Measuring the contribution of randomness, exposure, weather and daylight to the variation in road accident counts.” Accid. Anal. Prev., 27(1), 1–20.
Haleem, K., Abdel-Aty, M., and Mackie, K. (2010). “Using a reliability process to reduce uncertainty in predicting crashes at unsignalized intersections.” Accid. Anal. Prev., 42(2), 654–666.
Harwood, D., Council, F. M., Hauer, E., Hughes, W., and Vogt, A. (2002). Prediction of the expected safety performance of rural two-lane highways, Federal Highway Administration, Washington, DC.
Hauer, E. (1997). Observational before-after studies in road safety, Pergamon Press, Oxford, U.K.
Hauer, E., and Bamfo, J. (1997). “Two tools for finding what function links the dependent variable to the explanatory variables.” Proc., ICTCT Conf., Lund, Sweden.
Hirst, W. M., Mountain, L. J., and Maher, M. J. (2004). “Sources of error in road safety scheme evaluation: A quantified comparison of current methods.” Accid. Anal. Prev., 36(5), 705–715.
International Traffic Safety Data and Analysis Group (IRTAD). (2011). Road safety annual report 2011, OECD/ITF 2012, 342.
Lord, D., and Mahlawat, M. (2009). “Examining the application of aggregated and disagregated Poisson-gamma models subjected to low sample mean bias.” Transportation Research Record 2136, Transportation Research Board, 1–10.
Moreira, M. E. P., Neto, W. A. P., Cunto, F., Aragão, D. P., Jr., and Santos, J. B. (2011). “Integrated system for traffic crash data collection-iSiat.” Proc., XXY ANPET - Congresso de Ensino e Pesquisa em Transportes, Associação de Pesquisa e Ensino em Transportes-ANPET, Brasil.
Oliveira, M. D. (2004). “The standard nature of the spatial-temporal variation of the urban traffic volume: Case study of Fortaleza.” Master’s thesis, Universidade Federal do Ceará, Fortaleza, Brazil.
Persaud, B., Lord, D., and Palminaso, J. (2002). “Calibration and transferability in developing accident prediction models for urban intersections.”, Transportation Research Board, Washington, DC, 57–64.
Queiroz, M. (2003). “Spatial analysis of traffic crashes in Fortaleza city.” Master’s thesis, Universidade Federal do Ceará, Fortaleza, Brazil.
Sacchi, E., Persaud, B., and Bassani, M. (2012). “Assessing international transferability of the highway safety manual crash prediction algorithm and its components.” Transportation Research Record 12279, Transportation Research Board, Washington, DC, 90–98.
Sawalha, Z., and Sayed, T. (2006). “Transferability of accident prediction models.” Saf. Sci., 44(3), 209–219.
Sistema de Informações de Acidentes de Trânsito (SIAT-FOR). (2009). Annual statistical report of road accidents in Fortaleza-2009, Fortaleza, Brazil.
Sun, X., Li, Y., Magri, D., and Shirazi, H. (2006). “Application of ‘highway safety manual’ draft chapter: Louisiana experience.”, Transportation Research Board, Washington, DC, 55–64.
Vogt, A., and Bared, J. (1998). “Accident models for two-lane rural segments and intersections.”, Transportation Research Board, Washington, DC, 18–29.
Wood, A. G., Mountain, L. J., Connors, R. D., Maher, M. J., and Ropkins, K. (2013). “Updating outdated predictive accident models.” Accid. Anal. Prev., 55, 54–66.
World Health Organization (WHO). (2013). Global status report on road safety 2013: Supporting a decade of action, Geneva, Switzerland.
Xie, F., Gladhill, K., Dixon, K., and Monsere, C. (2011). “Calibrating the highway safety manual predictive models for Oregon state highways.” Proc., 90th Annual Meeting of Transportatioon Research Board, Transportation Research Board, Washington, DC, 1–9.
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© 2014 American Society of Civil Engineers.
History
Received: Jan 2, 2014
Accepted: Jul 9, 2014
Published online: Aug 11, 2014
Published in print: Jan 1, 2015
Discussion open until: Jan 11, 2015
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