Traffic operation and safety condition analysis of signalized intersections

Radha, Mustafa Mohamed; Ewadh, Hussein Ali

doi:10.30772/qjes.2024.149964.1245

	Traffic operation and safety condition analysis of signalized intersections
Al-Qadisiyah Journal for Engineering Sciences
Article 6, Volume 19, Issue 2, June 2026, Pages 203-210 PDF (7.87 M)
Document Type: Research Paper
DOI: 10.30772/qjes.2024.149964.1245
Authors
Mustafa Mohamed Radha; Hussein Ali Ewadh^*
Department of Civil Engineering , College of Engineering, University of Babylon, Babylon, Iraq
Abstract
In situations where reliable crash data is unavailable, Surrogate Safety Measures (SSMs) become valuable tools for traffic safety research. This study focuses on assessing traffic safety at signalized intersections, specifically examining how traffic operations such as stopped delay time and Level of Service affect hourly traffic conflicts using surrogate measures. Three four-leg signalized junctions in Karbala City were selected. Data on traffic volume and conflicts were collected using video cameras managed by the Karbala Traffic Police. The VISSIM software was utilized for traffic operation analysis, which then served as input for the Surrogate Safety Assessment Model (SSAM) software. The results show that simulation-based hourly traffic conflicts increase as stopped delay time increases, with a correlation coefficient between them ranging from R² = (0.9127-0.7533). Specifically, stopped delay values ranged from 117 seconds at the Sayed Jawda intersection (considered high-risk) to 79 seconds at the Al-Sofaraa intersection (considered low-risk). Rear-end conflicts accounted for the highest percentage of total conflicts, reaching 63%, 58%, and 66% at the respective intersections. This high percentage is attributed to rear-end conflicts predominantly occurring within the same approach in the traffic queue. This research provides valuable insights into evaluating safety at signalized intersections in urban areas and serves as an additional reference for future road safety studies. This study differs from previous research by emphasizing the correlation between stopped delay time and the frequency of hourly traffic conflicts using SSAM software. This study provides a more nuanced understanding of the relationship between operational characteristics and safety at signalized intersections.
Keywords
Traffic safety; VISSIM; SSAM; Four-leg intersection; Traffic operations

References
M. B. Mahdi, A. K. Alrawi, and L. V. Leong, “Compatibility between delay functions and highway capacity manual on iraqi highways,” Open Engineering, vol. 12, no. 1, pp. 359–372, 2022. [Online]. Available: https://doi.org/10.1515/eng-2022-0028 H. Joni and M. Hikmatt, “Assessment at al-ameer signalized intersection in samawa city,” in MATEC Web of Conferences. EDP Sciences, 2018, p. 01039. [Online]. Available: https://www.matec-conferences.org/articles/matecconf/abs/2018/21/matecconf bcee32018 01039/matecconf bcee32018 01039.html Transportation Research Board, Highway Capacity Manual (HCM 2010). Washington, DC: National Research Council, 2010. [Online]. Available: https://www.sciencedirect.com/topics/engineering/highway-capacity-manual T. G. Abate, “Evaluating the performance of signalized intersection and the associated economic impact of congestion: A case study on ras mekonnen street of addis ababa, ethiopia,” Master’s thesis, Addis Ababa University, 2014. F. L. Mannering and C. R. Bhat, “Analytic methods in accident research: Methodological frontier and future directions,” Analytic Methods in Accident Research, vol. 1, pp. 1–22, 2014. [Online]. Available: https://doi.org/10.1016/j.amar.2013.09.001 World Health Organization, Global Status Report on Road Safety 2015. World Health Organization, 2015. D. Lord and F. Mannering, “The statistical analysis of crash-frequency data: A review and assessment of methodological alternatives,” Transportation Research Part A: Policy and Practice, vol. 44, no. 5, pp. 291–305, 2010. [Online]. Available: https://doi.org/10.1016/j.tra.2010.02.001 C. Caliendo and M. Guida, “Microsimulation approach for predicting crashes at unsignalized intersections using traffic conflicts,” Journal of Transportation Engineering, vol. 138, no. 12, pp. 1453–1467, 2012. [Online]. Available: https://doi.org/10.1061/(ASCE)TE.1943-5436.0000439 S. Abd-alzahraa and H. Ewadh, “Simulated surrogate measures to assess the effectiveness of countermeasures at signalized intersections,” Heritage and Sustainable Development, vol. 6, no. 1, pp. 21–32, 2024. [Online]. Available: https://doi.org/10.37532/hsd.2024.6(1).21-32 V. Astarita, C. Caliendo, V. P. Giofr`e, and I. Russo, “Surrogate safety measures from traffic simulation: Validation of safety indicators with intersection traffic crash data,” Sustainability, vol. 12, no. 17, p. 6974, 2020. [Online]. Available: https://doi.org/10.3390/su12176974 H. A. Ewadh, “A sustainable strategy to upgrade safety at traffic system,” Journal of Kerbala University, vol. 13, no. 1, pp. 124–130, 2017. Central Statistical Organization Iraq, Ministry of Planning, Republic of Iraq, “Statistical report,” Ministry of Planning, Republic of Iraq, Tech. Rep., 2022. C. Hyd´en, “The development of a method for traffic safety evaluation: The swedish traffic conflicts technique,” Lund Institute of Technology, Department, Tech. Rep. 70, 1987. [Online]. Available: https://trid.trb.org/View/239059 National Research Council (US), Transportation Research Board, Task Force on Development of the Highway Safety Manual, Transportation Officials, and Joint Task Force on the Highway Safety Manual, Highway Safety Manual. AASHTO, 2010. D. Gettman and L. Head, “Surrogate safety measures from traffic simulation models,” Transportation Research Record, vol. 1840, no. 1, pp. 104–115, 2003. [Online]. Available: https://doi.org/10.3141/1840-12 S. Y. Koh, Doina, and H. C. Chin, “Traffic simulation modeling vissim,” National University of Singapore, Faculty of Engineering, Civil Engineering Department, Tech. Rep., 2009. D. Gettman, L. Pu, T. Sayed, and S. G. Shelby, “Surrogate safety assessment model and validation,” Turner-Fairbank Highway Research Center, Tech. Rep., 2008. [Online]. Available: https://rosap.ntl.bts.gov/view/dot/35896 D. Muley, M. Ghanim, and M. Kharbeche, “Prediction of traffic conflicts at signalized intersections using ssam,” Procedia Computer Science, vol. 130, pp. 255–262, 2018. [Online]. Available: https://doi.org/10.1016/j.procs.2018.04.037 T. Sayed and S. Zein, “Traffic conflict standards for intersections,” Transport Planning and Technology, vol. 22, no. 4, pp. 309–323, 1999. [Online]. Available: https://doi.org/10.1080/03081069908717634
Statistics Article View: 452 PDF Download: 215