ABSTRACT
Chapter 1 starts at the very beginning, with a description of the type of endeavor that is accident reconstruction. Whether as an orientation for beginning reconstructionists or as a refresher for experienced ones, familiar concepts such as units, dimensions, accuracy, precision, and significant figures are presented so as to promote clarity of communication. First principles that are the basis of accident reconstruction—Newton’s Laws of Motion—are set out in a manner as close to their original form as possible. Coordinate systems and reference frames are discussed. The phases of a crash are introduced so as to compare the force levels applied to an accident vehicle. Other first principles—Energy and Momentum Conservation Laws—are discussed. The concept of a crush zone is introduced, along with a description of what constitutes a crush zone. Acceleration, velocity, and displacement are defined and related to one another. Velocity change as a measure of crash severity is discussed, along with the concept of equivalence. The objectives of accident reconstruction efforts are described. Finally, forward-looking techniques, (simulations), are contrasted to backward-looking methods (reconstructions), which are the focus of most of the ensuing chapters.
