Braking systems on all combinations of vehicles (Classification C-4, RCW 46.37.351) shall have a deceleration ability of fourteen feet per second squared, and a maximum stopping distance of forty feet from a speed of twenty miles per hour, such distance to be measured from the point at which movement of the service brake pedal or control begins and on a flat (less than one percent grade), smooth, dry, hard surface, free from loose material. (Ord. 2546 § 2 (part), 2010: Ord. 577 § 22, 1972).