ABSTRACT
Typically, the crash phase is thought of as having a distinct duration: from the time the undeformed vehicles first touch, to the time when they cease to be in contact with one another. The former is a little easier to define and detect than the latter, which can be appreciated by analyzing crash test data. (Even with contact switches in the crush zones, it may be difficult to tell just when the vehicles separate. We can generally expect various locations in the contact surfaces to separate at various points in time, particularly if the vehicles exit the crash with some yaw velocity relative to one another.) Watching high-speed video coverage may not be that edifying. Often the crash test analyst must be content with defining a certain resultant acceleration below which a vehicle is deemed to be acted on by tire forces only, and not contact forces from the collision partner. After that time, the analyst deems the vehicles to be separated.
