Investigation of traffic conflicts at signalised intersections in Warsaw

Although traffic safety situation in general is improving, the numbers of pedestrians and cyclists hit when crossing a road have not significantly decreased recently. Based on police accident records for years 2010-2014, some 735 pedestrians and 505 cyclists were hit by motor vehicles in Warsaw. Investigation reported in this paper is a part of the European project InDeV. One aim of the project is to find correlation between accidents and traffic conflicts and thus provide a solid base for using surrogate safety measures as safety diagnostic tools. Three typical signalised intersections in Warsaw were selected for video recording. Relevant encounters between motor vehicles and vulnerable road users (pedestrians and cyclists) were identified and analysed using programs RUBA and T-Analyst. The paper describes the semiautomatic video data processing and problems regarding some technical and methodological aspects of conflict detection. Based on video analysis of 24 hours of recording for each intersection, preliminary characteristics of encounters between pedestrians/cyclists and motorised vehicles have been developed. Statistical distributions of encounter parameters such as time-to-collision (TTC) and post-encroachment time (PET) are presented. These will be used in the development of appropriate safety indicators