Full Frontal Car Crash Tests: Empirical Evidence About Shape of Deceleration Pulses

If deceleration is constant in a vehicle crash, deformation of the vehicle is a function of impact speed and impact duration. The ratio of actual deformation to this idealized quantity may be used to summarize the shape and effects of the deceleration pulse. This ratio reflects whether the pulse is front-loaded (acceleration is greater early in the pulse than later), or back-loaded (acceleration is less early in the pulse than later). Further interpretation of the ratio is possible within simple families of pulse shape, such as M. Huang's TESW (Tipped Equivalent Square Wave) model and the triangular pulse. This paper reviews published test results and summaries of datasets. It is found that pulses tend to be back-loaded. However, this conclusion is sensitive to how deformation, speed, and duration are calculated.