Brake performance

Every motor vehicle or combination of motor vehicles, according to its type, shall be capable at all times and under all conditions of loading, of stopping on a dry, smooth, level pavement of approximately .6 co-efficient of friction and free from loose material, upon application of the service (foot) brake, within the distances specified below, or shall be capable of decelerating at a sustained rate corresponding to these distances: Approximate deceleration Feet to stop from in feet per second twenty miles per hour per second Vehicles or combination of vehicles having brakes on all wheels ..... 30 14 Vehicles or combinations of vehicles not having brakes on all wheels ..... 45 9.5 The stopping ability, or decelerating capacity, of a motor vehicle or combination of motor vehicles shall be determined by an approved instrument or an approved machine capable of being read in feet to stop from a speed of twenty miles per hour, deceleration in feet per second per second or other equivalent units. Agricultural machinery and implements, road machinery, road rollers, traction engines and farm tractors when used upon any highway shall have means adequate to control the movement of and to stop and to hold such machines on any up or down grade upon which they may be operated. No person shall hereafter drive, move or be in custody of any motor vehicle or combination of motor vehicles unless such vehicle or combination is capable of being controlled, stopped and held as provided for herein.