Horns and backup alarms for surface equipment.

§ 57.14132 Horns and backup alarms for surface equipment. (a) Manually-operated horns or other audible warning devices provided on self-propelled mobile equipment as a safety device shall be maintained in a functional condition. (b)(1) When the operator has an obstructed view to the rear, self-propelled mobile equipment shall have— (i) An automatic reverse-activated signal alarm; (ii) A wheel-mounted bell alarm which sounds at least once for each three feet of reverse movement; (iii) A discriminating backup alarm that covers the area of obstructed view; or (iv) An observer to signal when it is safe to back up. (2) Alarms shall be audible above the surrounding noise level. (3) An automatic reverse-activated strobe light may be used at night in lieu of an audible reverse alarm. (c) This standard does not apply to rail equipment.