Status of signalized intersection safety-A case study of Kolkata

Urban signalized intersections in Indian cities experience a high share of fatalities and serious injuries. However, assessment of safety using rigorous statistical technique is still in an early stage in India, primarily due to challenges in obtaining crash data, road geometric and traffic data. This study intended to focus on safety issues associated with the planning, design, and operation of signalized intersections, and identify the risk factors affecting the frequency and severity of crashes. Assuming that user behavior is influenced by the design and traffic operational characteristics of a location, this study specifically aims to investigate the effects of geometric, infrastructural, traffic control and land use parameters on the number of crashes and their severity across 52 signalized intersections of Kolkata. These data were associated with crash records from 2011 through 2014, to extract important insights, using statistical tests such as correlation analysis and independent samples t-test, as well as multivariate regression analysis for crash prediction purposes. Based on the assessments carried out in this study, there is evidence that factors such as total approach traffic volume, blocked carriageways, traffic configuration, presence of protected right turning phase, type of minor road, tram stops, etc. significantly affect the frequency of crashes while presence of all-red time, protected right turning phase, blocked carriageway, non-motorized traffic, and visibility of road markings affect the severity of crashes at signalized intersections of Kolkata. In the absence of other road traffic safety studies involving rigorous statistical analysis, these findings can significantly contribute to policy-making decisions that are aimed at improving the safety of signalized intersections in the city of Kolkata.