Improving Road Safety Using Intelligent Transportation Systems (ITS): A Comparative Before-and-After Evaluation of an Integrated ITS Framework in an Urban Corridor, Baghdad, Iraq

Abstract

Road traffic crashes are among the major contributors to fatalities and morbidity in the world, but infrastructure-based road safety measures are becoming inadequate in the context of busy and congested road systems in urban areas. This study aims to assess the role of ITS in improving road safety through application of analytical applied, quasi-experimental before-after methodological approach on a signalized urban corridor of Baghdad, Iraq. The ITS under evaluation comprises adaptive traffic signaling, speed detection cameras, red light violation cameras, variable message signs, automatic incident detection, pedestrian warning system, and emergency coordination center.Ten indicators were compiled from traffic-police records, ITS camera and controller logs, emergency-service dispatch records, and structured field observation, and were synthesised into a composite Road Safety Performance Index (SPI) computed as the equally weighted mean of five sub-scores covering crash reduction, violation reduction, response-time improvement, intersection safety, and pedestrian safety. Before-after differences were tested using a Poisson rate-ratio z-test with 95% confidence intervals, and compositional changes were tested using chi-square tests of homogeneity with effect-size reporting (φ, Cramér’s V). Following ITS deployment, total accidents fell significantly from 126 to 82 (−34.9%, p = 0.002), recorded traffic violations fell significantly by 38.7% (p < .001), and total emergency response time fell from 27.4 to 16.3 minutes (−40.5%); the composite index rose from 48.2 to 72.8. The chi-square analysis further showed that the relative severity mix of accidents did not change significantly (p = 0.811), indicating that the decline in accident severity was driven by the reduction in overall crash volume rather than a selective reduction in the most severe crashes — while the 60.0% reduction in fatal accidents specifically, based on only five and two events, did not reach statistical significance (p = 0.257), underscoring the importance of reporting significance alongside percentage change for rare, high-severity outcomes. Based on these results, it is clear that the use of ITS technology as part of an integrated approach to road safety could generate significant improvements on a statistical level as well as on other levels. It is suggested that ITS needs to be considered as a holistic approach to road safety planning and assessment in terms of a system-level approach to urban corridors in the area.