20.4 Dump Trucks: On-Road and Off-Road Operation

Dump Trucks: On-Road and Off-Road Operation

Types of Dump Trucks

Section 20.3 covers ADTs and rigid haulers in detail. This section focuses on practices that apply to every dump truck.

Licensing and Weight Limits

Under federal CDL rules (49 CFR Part 383):

• Class B covers a single vehicle with a gross vehicle weight rating (GVWR) of 26,001 pounds or more, which includes most tandem dump trucks.
• Class A covers combinations with a gross combination weight rating of 26,001 pounds or more when the towed unit's GVWR exceeds 10,000 pounds, such as end-dump and bottom-dump trailers.
• CDL drivers are also subject to federal drug and alcohol testing.

On the Interstate system, federal limits are 20,000 pounds on a single axle, 34,000 pounds on a tandem axle, and 80,000 pounds gross, subject to the federal bridge formula. States set limits for other roads and issue overweight permits. Lift axles must be lowered as state rules require to spread the load. Overloading lengthens stopping distance, overheats brakes, and damages tires and roads.

Inspection Before Each Shift

OSHA 1926.601(b)(14) requires that every vehicle on a construction site be checked at the beginning of each shift, including service brakes and trailer brake connections, the parking brake, emergency stopping system, tires, horn, steering, coupling devices, seat belts, operating controls, and safety devices. Defects must be corrected before the vehicle goes into service. Highway drivers must also be satisfied that the vehicle is safe before driving and review the last driver vehicle inspection report (49 CFR 396.13).

Dump-specific checks include:

• Hoist cylinder, hoses, and body hinge pins.
• The PTO and hoist control, including the latch that prevents accidental tripping.
• Tailgate latches, chains, and hinges.
• The body-up warning light or alarm.
• The body support prop.
• Tarp system, mirrors, lights, and the backup alarm.

Loading

• Position the truck where the loader or excavator operator can load it without swinging over people.
• OSHA 1926.651(e) requires employees to stand away from vehicles being loaded or unloaded. The driver may stay in the cab only if the truck has a cab shield or canopy adequate to protect against falling material (1926.601(b)(6)).
• Load evenly, centered side to side, and not above the sideboards.
• Federal rules require loose cargo to be loaded so it does not leak, spill, blow, or fall from the vehicle (49 CFR 393.100), and many states require tarps.

Dumping Safely

1. Choose firm, level ground. Soft fill can give way under one rear wheel as the body rises.
2. Line up straight. Dump with the truck straight, and with a trailer in line with its tractor.
3. Look up. Check for power lines, trees, and structures before raising the body. Equipment near power lines must keep at least 10 feet of clearance from lines rated 50 kV or less, with more for higher voltages (1926.600(a)(6)).
4. Watch for sticky or frozen loads. Material that hangs up in the front of a raised body puts a heavy weight high and forward and can tip the truck. Do not rock or jerk the truck to free it; lower the body and get the load loosened.
5. Consider wind and slope. A crosswind on a raised end-dump body or a side slope can push the truck over.
6. Keep the tailgate area clear. Tailgate trip handles must let the operator stay in the clear while dumping (1926.601(b)(12)). No one should stand behind or beside the truck during dumping.
7. Lower the body fully and disengage the PTO before driving away. A raised body can strike overhead lines and structures.

When spreading material, release it at a slow, steady speed with the tailgate set as the job requires. At fill edges and stockpiles, keep the required setback from the crest or dump against a berm.

Backing and Spotters

Under 1926.601(b)(4), a vehicle with an obstructed rear view may back up only if it has a reverse alarm audible above the surrounding noise or an observer signals that it is safe. Good backing practice includes:

• Use one designated spotter, agreed hand signals, and eye contact.
• If you lose sight of the spotter, stop.
• Spotters stay out of the truck's path and away from the space between the truck and fixed objects.
• Follow the site's internal traffic control plan, which separates trucks from workers on foot.

Working Under a Raised Body

1926.601(b)(10) requires trucks with dump bodies to have a positive means of support, permanently attached and capable of being locked in position, to prevent accidental lowering during maintenance or inspection. Lever controls for hoisting or dumping must have a latch to prevent accidental starting or tripping (1926.601(b)(11)). Never rely on the hoist cylinder alone. Place and lock the body prop, shut down the engine, and lock out the controls before anyone reaches under the body.