321.431  Performance ability.
  1.  The service brakes upon any motor vehicle or combination of motor vehicles, when upon dry asphalt or concrete pavement surface free from loose material where the grade does not exceed one percent, when traveling twenty miles an hour shall be adequate:
  a.  To stop such vehicle or vehicles having a gross weight of less than five thousand pounds within a distance of thirty feet.
  b.  To stop such vehicle or vehicles having a gross weight in excess of five thousand pounds within a distance of forty-five feet.
  2.  Under the above conditions the hand brake shall be adequate to hold such vehicle or vehicles stationary on any grade upon which operated.
  3.  Under the above conditions the service brakes upon a motor vehicle equipped with two-wheel brakes only, and when permitted hereunder, shall be adequate to stop the vehicle within a distance of forty-five feet and the hand brake adequate to stop the vehicle within a distance of fifty-five feet.
  4.  All braking distances specified in this section shall apply to all vehicles mentioned, whether such vehicles are not loaded or are loaded to the maximum capacity permitted under this chapter.
  5.  All brakes shall be maintained in good working order and shall be so adjusted as to operate as equally as practicable with respect to the wheels on opposite sides of the vehicle.
  6.  A person who violates this section commits a simple misdemeanor.
[S13, §1571-m17; C24, 27, 31, 35, §5039; C39, §5034.40; C46, 50, 54, 58, 62, 66, 71, 73, 75, 77, 79, 81, §321.431]
2010 Acts, ch 1140, §14
Referred to in §321.189, §321.430, §321.464