Dump Truck Safety

As end-dump truck bodies and semitrailers have increased in length, unit rollovers have also increased. Construction and trucking sectors should be aware of this tip-over hazard, the contributing conditions and methods of prevention.

Stability

The primary tip-over hazard is the stability of the unit when the box is in the raised position. There is an increased risk of tip-over when the center of gravity of the box and load is not roughly between the frame rails of the unit. Even a slight slope can be enough to cause tipping if dumping material does not flow out of the top portion of the box. Stability is adversely affected by the following factors:

• The truck is not on a level surface when dumping
• Material does not flow out of the top portion of the raised box
• The rear wheels settle unevenly as the load moves to the rear during dumping
• Wind
• Cold weather may cause materials to freeze to the box and stick when dumping
• Mechanical issues such as:
  • Poor rear suspension systems on one side of the vehicle
  • Uneven tire pressure in rear wheels
  • Worn or inadequate pins or other components of the lifting system
  • Worn or inadequate lifting cylinders

Hazard Control

Due to stability concerns with semitrailers, they should not be used for hauling in rough grading or fill areas where surfaces are often uneven or loosely compacted. Straight trucks and pup trailers are more appropriate for these dump areas. Where hauling and dumping are all on-site, straight trucks or off-highway vehicles are good choices. If aggregates are being spread for road construction, belly-dump semitrailers are more appropriate than end-dump semitrailers.

Vehicle Maintenance

Vehicle maintenance plays an important role in preventing tip-overs. Perform these tasks:

• Check tire pressures daily (tire pressure should be the same on both sides of the vehicle)
• Examine and lubricate pins and bushings regularly
• Inspect suspension systems while the vehicle is loaded to ensure they work properly and provide even suspension—replace weak suspension systems immediately
• Inspect hoist cylinders regularly and replace worn cylinders with the same size and type
• Make sure that repairs to boxes leave the bottom and sides clear and unrestricted as rough patchwork repairs near the top of the box can catch and hold sticky materials

Loading and Dumping

Front-to-back loading of the box should meet allowable gross and axle weight limitations set by the U.S. Department of Transportation. If material is likely to flow poorly, lighten the load at the top end of the box. Always load as evenly as possible from side-to-side. Box liners will help most materials flow more smoothly during dumping and will also help keep the box in good condition. Additional dumping guidelines include:

• Train operators to recognize areas hazardous to dumping, such as soft or uneven surfaces and inadequately compacted fill
• Ensure that operators know to check that the tailgate is unlocked and that the vehicle is on a reasonably level surface
• Distribute the load evenly; This will help keep your truck as stable as possible
• Make sure your truck has liner so the load will flow our evenly
• Never drive while the truck bed is raised
• Trucks should not dump when they are parked side-by-side with another vehicle; when a dump unit tips over, it is often the operator in the adjoining vehicle that is injured
• Warning other personnel, such as dozer operators, surveyors and spotters, not to work near a dumping truck in case it tips over