The safety of standing passengers is a major challenge for the development of public transportation. One of the key issues is related to minor but frequent incidents. For the current study, complementary experiments performed with 4 free standing subjects were analyzed in order to highlight thepossible effects of an obstacle on head kinematics. The obstacle was simulated by elastic ropes that were positioned in front of the subjects at a distance corresponding to their maximal balance recovery performance. Eachsubject was submitted to two different levels of perturbations. In this study, the effect of an obstacle on the kinematics of standing volunteers subjected to sudden accelerations could be observed and quantified. Cautionshould be used when interpreting the results as the number of volunteers was very limited (four). However the fact that similar effects were observed on all four volunteers is encouraging and the addition of more volunteers in future studies is expected to confirm the current results. Another limitation of the current study was the extreme simplification of the obstacle (two elastic ropes). Future study should evaluate the influence of different obstacles that are more representative of an actual interior, including the presence of obstacles in front of the head of the subjects. Despite all those limitations, the first results obtained in this study indicate that: 1/ the distance to stop decreases in presence of an obstacle, 2/ but that the main part of the head kinematics is only slightly affected. More specifically, the influence of the obstacle on the peak head velocity is almost non-existent, both in terms of amplitude and location. Even if more experimental data are needed, the results of this study tend to confirmthe hypothesis made in the previous study, which was that the balance recovery observed without obstacle were close to represent the maximal performance of the subjects. Therefore, this study tends to suggest that the results without obstacle can reasonably be used even if an obstacle is located in front of the subjects. For the covering abstract see ITRD E141762.
Samenvatting