3.9.2 Parking brakes. Manually applied parking brakes shall be furnished. Parking brakes
shall conform to Federal Motor Carrier Safety Regulation 393.41. When brake cables are used,
the cables shall be corrosion-resistant steel. Provisions shall be made for slack adjustment.
Lubrication fittings shall be provided.
3.10 Coupling device and towbar. The trailer shall be furnished with a 2-inch ball coupling
device with automatic latch which secures the trailer when the ball is engaged on the towing
vehicle. A split hitch arm assembly shall be provided. The hitch arm assembly shall permit the
trailer body to be lowered to ground level and raised to hauling position without uncoupling the
trailer from the towing vehicle. Means shall be provided to lock the split hitch arm assembly in a
longitudinal plane, when the trailer is in travel position. Safety chains shall be provided. Chains
shall conform to Federal Motor Carrier Safety Regulation 393.70(d).
3.11 Load leveler. A load leveling system which maintains the trailer body in level position
on the transverse plane while being lowered or raised, regardless of weight distribution in the
cargo body, shall be provided.
3.12 Landing leg. The trailer shall be equipped with a retractable landing leg with caster type
landing wheel, with cranking handle (rigid or swivel type) permanently installed. The landing leg
shall have a vertical range of adjustment. The landing leg shall permit the operator to lower the
cargo body to ground level. When the cargo body is in its maximum travel position, the landing
leg shall have sufficient vertical adjustment to permit the operator to couple the coupling device
to the towing vehicle when the top of the 2-inch ball of the towing device of the towing vehicle is
17.75 inches above ground level. The landing leg and related parts shall withstand, without
permanent deformation, the combined static and dynamic forces due to the proportionate weight
of the gross weight and impacts during coupling and uncoupling operations. The landing leg shall
operate freely, and shall be protected from malfunctioning by the accumulation of foreign matter.
When placed in travel position, the landing leg shall remain positively looked to provide ground
clearance in the course of normal towing operations. The landing leg wheel, and any rotating
components of the landing leg, shall be fitted with anti-friction bearings. Means shall be provided
to lubricate the landing leg assembly and the wheel.
3.13 Lighting. The electrical lighting system shall be 12-volts. All vehicle lights, reflectors,
and wiring (including electric brakes) shall conform to Federal Motor Carrier Safety Regulations
393.15, 393.19, 393.20, 393.22, 393.23, 393.25, 393.26 (a, b, c and d), and 393.27 through
393.33. Lights and reflectors shall not be mounted on vehicle bumpers.
3.13.1 Electrical receptacle. A trailer electrical receptacle with a spring-loaded cover
assembly shall be installed on the forward end of the drawbar. The receptacle shall conform to
SAE J560, with conductors connected and color-coded as specified in SAE J560.