|Abstract||OBJECT OF THE INVESTIGATION 1.1 This project was entirely financed by the Australian Road Research Board. Its object was defined as follows: 'To gather data in Australian conditions basic to the design of roads, traffic organization and vehicles, by the objective study of the medical and engineering aspects of injury-producing accidents.'
METHODS 1.2 The investigating team consisted of a doctor (G. A. Ryan) and a mechanical engineer (A. J. McLean) in a vehicle equipped with a two-way voice radio tuned to the ambulance frequency. Working to a carefully designed statistical plan the team attended in 1963 and 1964 a representative sample comprising 12.3 per cent of those traffic accidents in metropolitan Adelaide to which an ambulance was called. Some few sources of bias were present in the sampling procedure, partly avoidable, partly unavoidable. These are discussed in the body of this report (para. 3.26). 1.3 A rapid but thorough investigation was made at the scene of the accident. The doctor recorded age, sex, height, weight and seated positions of the participants, and the details of their injuries, while the engineer studied the vehicular and environmental aspects. A comprehensive set of photographs was taken. Together the two members determined when possible what particular structures caused the injuries. The victims were then followed to the hospitals, where their injuries and personal particulars were recorded in more detail. Their subsequent progress in hospital was followed until discharge or death. A full necropsy was performed on every victim who died. 1.4 In a similar way the vehicles were followed when necessary to the repair shops, where damage could be studied in detail and at leisure. In many cases an estimate of the cost of repair was obtained. 1.5 A measured sketch plan was made of the scene of every accident. In numerous cases the scene was revisited to complete the details of the site plan, and most of these sketches were subsequently drawn for the permanent record. Many of them are printed in this report. 1.6 As far as possible, the information obtained on both medical and engineering aspects was recorded in a quantitative way so that subsequent statistical analysis could be performed. Some items could be measured with reasonable accuracy, for example the length and direction of skid marks. Others were estimates of varying precision, such as travelling speed of the vehicles and their speed at impact. Other items again, such as the degree of injury to the victim, were recorded as ranked scores according to a predetermined code, which was very similar to and was based on the code used by the Automotive Crash Injury Research organization of Cornell University, U.S.A. In gensral these estimates and measurements proved satisfactory enough for subsequent quite detailed statistical study, and yet they were simple to obtain, and therefore they would be usable and useful (in our opinion) in the hands of trained but non-professional accident investigators.