Pedestrians often suffer severe injuries from collisions with trams. In most scientific studies, principle accident circumstances are investigated, but the optimisation of the tram front-end design is rarely addressed. Hence, the objective of this study was (a) to optimise the tram front?end design to reduce pedestrian injury risk and (b) to develop practical design guidelines for public transport services and manufacturers. Typical accident scenarios were defined based on an analysis of tram-pedestrian collisions in a major Swiss city as well as on cases reported in the literature. In the simulation environment Madymo, mathematical models of five different tram front geometries were tested against models of a 50th percentile and a 6-year old pedestrian dummy. Kinematics of the struck pedestrians were analysed and the injury criteria HIC, head acceleration and/or head impact velocity were compared. Particularly the primary impact was addressed, but the secondary impact as well as the situation where a pedestrian ends up underneath the tram was also investigated. Potentially critical areas in different tram front geometries such as the front cover, the windscreen, the a-pillars or the ground clearance were identified. Based on these findings, front-end design guidelines were established together with Swiss public transport services. (Author/publisher)
Samenvatting