Building the European Road Safety Observatory. SafetyNet. Deliverable 5.8: In-depth accident causation database and analysis report

The SafetyNet project is an Integrated Project (IP) which was developed as part of the European Commission’s 6th Framework programme. SafetyNet has built the foundations of a European Road Safety Observatory (ERSO) which can be used by the European Commission for the purposes of policy review and development. The SafetyNet project is divided into seven main Work Packages each of which deal with specific aspects of road safety research (see www.erso.eu). The objective of the SafetyNet Work Package 5, Task 2 was to develop an in-depth European accident causation database to identify risk factors that contribute to road accidents. To assist in the analysis of the accident causation a method, known as SNACS, was further developed, tested and revised throughout the project. The accident investigations were performed by existing multidisciplinary teams within the partnership which have many years of experience. The accident causation database was developed in two parts; a set of general variables about the accident, vehicle, road environment and road users and a part which was dedicated to the accident causation analysis performed with the SafetyNet Accident Causation System (SNACS). The definitions for the general variables and values as well as the SNACS method were piloted and revised several times before data collection commenced to ensure high quality in the gathered data. In total, 1006 accident cases were investigated which include 1833 vehicles and pedestrians. In the aggregated analysis these vehicles were grouped according to their trajectory prior to the accident and the groups were; Vehicles leaving their lane (n = 354), Vehicles encountering something in their lane (n = 537), Vehicles encountering another vehicle on crossing paths (n = 528) and Accidents involving slower moving vulnerable road users (n = 92 pedestrians; 95 Pedal Cyclists, 177 opponents) The aim of the analyses conducted was not to explore and evaluate the effectiveness of new technologies, but rather to demonstrate the potential uses for the accident causation database and identify common accident scenarios. The SNACS charts in the groups were aggregated to allow the most commonly occurring accident contributing factors to be identified. In the SNACS charts the information is rich and detailed and it is by nature complex as it reflects the complex interactions between the road users, vehicles and environment that occur in an accident. The SNACS method assists in the process of identifying patterns that will allow the most common accident contributing factors to be focused on when designing countermeasures.