To improve the safety of wheelchair occupants using both private and public transportation, effort is being focused through the International Standards Organisation (ISO) to produce standards for Wheelchair Tiedown and Occupant Restraint Systems (WTORS) (ISO/CD/10542) and Transportable Wheelchair Systems (TWS) (ISO/CD/7176-19). To ensure the structural integrity of the systems, these standards define a crash test protocol, which includes the use of a test wheelchair (ISO-W/C). In the UK the diagonal strap of a lap and diagonal (L/D) wheelchair occupant restraint is either anchored to the floor of the vehicle or to the B pillar. This paper reports a programme of frontal impact tests using the ISO-W/C test chair in a forward facing mode, carried out at the impact facility of Middlesex University, Road Safety Engineering Laboratory (MURSEL). The objective was to identify the influence of the diagonal strap anchorage position on the variation of loads in the WTORS. Two computer models were built using MADYMO and DYNAMAN respectively, validated by the experimental results, to predict the occupant response to impacts and hence provide data to optimise future system design. The results suggested that the `B pillar' anchorage configuration was superior to the floor anchorage in that it exhibited reduced occupant shoulder loads and wheelchair front wheel loads. (A)
Samenvatting