Assessment of physical evidence
The scientific investigation of accidents is a branch of forensic science. Forensic scientists will carefully examine the scene of a crime for physical evidence which can be subjected to analysis. The outcome of such analyses may assist the Court to determine guilt, innocence, fault or liability. Accident Investigators carry out their work in exactly the same way.
In road traffic accidents the primary physical evidence lies in the site details, the conditions which prevailed at the time of the accident, the state of the road, marks and debris on the road, the physical characteristics of the vehicles involved, the damage sustained by the vehicles, the injuries sustained by persons involved in the accident, the police plan, the police measurements, the police photographs, the police video and in the laws of physics which determine the movement of vehicles, cyclists and pedestrians before, during and after an accident.
Secondary physical evidence comes from the statements of witnesses when they refer to times, distances, speeds and locations. However, the validity and interpretation of such statements are matters for the Court to determine. Those parts of a statement which refer to physical parameters will sometimes have additional physical implications.
Further physical evidence comes from the results of major research programmes concerning road traffic matters.
The analysis of such evidence often involves the application of detailed mathematics, physical science and engineering. It is essential that the investigator can convey the results of his analysis to a Court without resorting to technicalities.