New features!!! Fully functional 29 Day Trial. Top menu access to all categories (purchased version only). Calculate speed from acceleration of passenger cars, heavy trucks and motorcycles. Calculate speed from skidmarks and acceleration, stopping distance, perception, reaction distance, convert miles per hour to feet per second, and determine speed of heavy trucks from skids. Calculates speed, time and distance related to traffic crashes. Tool can be used by insurance investigators, attorneys, police officers or any seeking answers to the physics of accident investigation. Self explanatory and easy menus.