30 CFR § 77.410
Mobile equipment; automatic warning devices.
(a) Mobile equipment such as front-end loaders, forklifts, tractors,
graders, and trucks, except pickup trucks with an unobstructed rear view,
shall be equipped with a warning device that--
(1) Gives an audible alarm when the equipment is put in
reverse; or
(2) Uses infrared light, ultrasonic waves, radar, or other
effective devices to detect objects or persons at the rear of the equipment,
and sounds an audible alarm when a person or object is detected. This type
of discriminating warning device shall--
(a)(2)(i) Have a sensing area of a sufficient size that would
allow endangered persons adequate time to get out of the danger zone.
(a)(2)(ii) Give audible and visual alarms inside the
operator's compartment and a audible alarm outside of the operator's
compartment when a person or object is detected in the sensing area; and
(a)(2)(iii) When the equipment is put in reverse, activate
and give a one-time audible and visual alarm inside the operator's
compartment and a one-time audible alarm outside the operator's
compartment.
(b) Alarms shall be audible above the surrounding noise levels.
(c) Warning devices shall be maintained in functional condition.
(d) An automatic reverse-activated strobe light may be substituted
for an audible alarm when mobile equipment is operated at night.
[54 FR 30517, July 20, 1989]