The basic philosophy in the early studies has been termed phenomenological testing. The method employed was to tow a crash vehicle into a controlled collision with a sign support and to record the collision incident on high-speed photography film, and observe the qualitative behaviour of the sign support subjected to a collision by an automobile. In later studies attempts were made to obtain displacement time information from the high speed film, and still later accelerometers mounted on the frame of the crash vehicle. were employed to provide a deceleration time trace on a recording oscillograph. The simultaneous use of photographic and electronic instrumentation has been the outgrowth of these earlier investigations. Acorollary activity was the development of an electronic computer program to simulate the collision incident. Phenomenological testing has been an important aspect in the testing procedure. Observation of films has produced a clear impression of a vehicle and sign behaviour. Improvements in camera technique and film data reduction, combined with electronic instrumentation and data reduction have augmented and extended the phenomenological testing. These improvements have produced quantitative analytical information, the mathematical model has been a product of the phenomenological testing and the quantitative testing.
Abstract