Crash Calc is a collection of the most commonly used formulas for traffic accident reconstruction. Available in both US (Imperial) and Metric measurements. Easily calculate your results and save them for your files, all done right on your phone. Never have to wait to get back to the office again. The application is broken down into seven logical categories of formulas. • Drag Factors – Calculate your drag factors by several different ways then adjust for braking, slope and super-elevation.