A small percentage of wheelchair users are unable to transfer from their wheelchair to a vehicle during transportation. Reasons for an occupant to remain in the wheelchair during transport may be the inability to safely transfer to a vehicle seat, the occupant's requirement of a specialist postural management wheelchair seating system or reliance on life support equipment attached to the wheelchair. The Rehabilitation Engineering Unit at Rookwood Hospital deal with people who require either a specialist postural support wheelchair seating system, life support equipment or both. To cater for such equipment the wheelchairs have to be modified to some degree and sometimes completely custom made. In performing modifications to the wheelchairs the Rehabilitation Engineering Unit take on the manufactures responsibilities, one of which is to ensure that the wheelchair is safe for use in transport. Standard crash tests for production wheelchairs are destructive so are impractical to use for bespoke wheelchair designs meaning that the Clinical Engineers at the Hospital have to rely on their best engineering judgement as to whether a wheelchair design is crash worthy or not. It was proposed that by using computer crash simulation techniques an informed judgement of the crashworthiness of the bespoke wheelchair designs could be attained. A series of computer models of occupied wheelchairs were created and validated against physical crash data performed on surrogate wheelchairs. These validated wheelchair computer models were then used to examine a series of different crash scenarios that provided the Clinical Engineers at Rookwood hospital with an informed process for virtually assessing the crashworthiness of their wheelchair designs. The validation results showed that the wheelchair crashworthiness could feasibly be predicted by computer simulation. This thesis concluded that attaching equipment to the wheelchair can increase both its horizontal displacement and the forces on the tiedowns securing the wheelchair to the vehicle chassis. Skewed impact simulations also highlighted the poor lateral restraint ability of the 4-point webbing tie-down system and also the importance of sufficient lateral support on the wheelchair for occupant protection.