The aim of the work was to assess the safety of wheelchair users when being transported on all M category vehicles in comparison with travellers seated in conventional seats (fitted with headrests). In cases where the safety of the wheelchair user was lower than that of other passengers, or considered unacceptable for other reasons, modifications were assessed. The approach to the work involved a programme of numerical simulation followed by an extensive programme of testing involving 37 individual sled impact tests. In addition, the safety of passengers under normal transit conditions was addressed. The work found that the heads and necks of wheelchair users were particularly vulnerable but that this could be addressed through the use of a head and back restraint. However, such a restraint should meet the requirements of ECE Regulation 17 for strength and energy absorption and the wheelchair should fit well up against the head and back restraint for maximum benefit. Further recommendations from the work were that an upper anchorage location for diagonal restraints is preferable to a floor mounted location and that the restraint anchorages should meet more rigorous strength requirements than are required at present. A protected space envelope for forward facing wheelchair passengers is also recommended. Under normal transit conditions a vertical stanchion is preferable to a horizontal bar in terms of preventing excessive movement of the wheelchair.