Abstract
The goal of the study was to analyse the kinematic and dynamic response of the human head during the primary impact of tram-pedestrian collisions. The anthropomorphic test device (dummy) was used for two collision scenarios: the frontal (dummy facing the approaching tram) and side impact (dummy standing with its shoulder towards the tram).
The crash tests were conducted with four different types of tram, typical for the Prague's public transportation, and at four different impact speeds (5, 10, 15, 20 km/h). The primary outcome variable was the resultant head acceleration.
The risk and severity of possible head injuries were analysed using the head injury criterion (HIC15) and the corresponding level of injury on the Abbreviated Injury Scale (AIS). The results of kinematic analysis showed that during the primary impact, the head of dummy always got hit by trams' front ends in the case of frontal impact while in the case of side impact, the head got only hit at higher speeds (15 and 20 km/h) with modern tram types.
The results of dynamic analysis showed an increasing trend of head impacts with higher speeds for all tram types and collision scenarios. However, the head acceleration was higher in the case of frontal impacts compared to side impacts.
The HIC15 did not exceed the value of 300 in any case and the probability of AIS3+ did not exceed 10%. The results suggest that the outcomes of tram-pedestrian collisions can be influenced by the tram type (its front-end design), impact speed, collision scenario, and the site of initial contact.