Rollover accidents are extremely dangerous for drivers and helpers and costly for the owner of the truck. There are often many contributing factors that cause a rollover; however, the number of accidents can be significantly reduced if drivers use a few basic tips.
Okay, let’s state the obvious … garbage trucks are not sports cars.
Garbage trucks are big, heavy, bulky, massive trucks with high centers of gravity. As such, they require a lot more skill to drive than a sports car. In addition, the weight distribution and the center of gravity of a garbage truck changes during the workday depending on the load. These variations, along with road and weather conditions, can dramatically alter the handling, stability, steering, braking and acceleration of a truck.
Empty Trucks and Full Trucks
When a truck is empty, most of the weight is carried on the front end. With Front End Loaders and Rear End Loaders, up to 60 to 70 percent of the weight of the truck will be placed on the front wheels when a truck is empty. As the truck is loaded, the weight will shift to the rear wheels. A fully loaded vehicle will see a complete reversal in weight distribution as 60 to 70 percent of the weight will rest on the rear wheels.
Roll-off trucks are entirely different in that loads are added immediately upon the box being hoisted onto the rails. The weight distribution of the roll-off truck will vary depending on the weight and placement of material inside the box. For this reason, roll-off drivers need to be ever mindful of the handling and responsiveness of the truck.
The Changing Center of Gravity
It’s all about the laws of physics. When a truck is turned, the weight of the truck shifts to the opposite side to which the driver is turning. Two things happen during a turn. First, the weight will shift and create more traction on one side of the truck than the other. Second, the center of gravity will shift.
Breaking and acceleration also impacts traction and the center of gravity of the truck. Braking too hard will cause the weight of the truck to move to the truck’s front wheels while removing weight off of the back axle. A combination of hard braking and turning can cause the weight to shift to the outside front tire. Anytime there is a dramatic shift in weight and the center of gravity, a rollover is possible.
Tips for Avoiding a Rollover
Drivers can eliminate rollover accidents if they take these precautions:
- Pay attention to surface conditions. Soft surfaces and un-level surfaces may potentially cause a rollover.
- Be alert for road shoulder conditions. Soft shoulders or no shoulders may cause a truck to tip and possibly roll or flip.
- Check tires and maintain correct tire pressure.
- Be aware of the truck’s center of gravity and realize that it changes depending on the load on the truck.
- Slow down before entering curves. Remember, posted speed limits are for cars. Trucks with high center of gravity should take extra precautions and slowly execute turns.
- Make sure your load is stable and secure, especially with roll-off boxes that may have been loaded unevenly.
When making a turn:
- Look ahead and plan the turn.
- Pick a proper entry point for the turn.
- Slow down before the turn and brake smoothly in a straight line when approaching the corner.
- Stay within the lane.
- Steer smoothly out of the turn.
- Step on the throttle to gently accelerate out of the corner.
Many rollover accidents occur because the driver of the garbage truck is traveling too fast and fails to properly negotiate a curve or turn resulting in the truck leaving the roadway. During safety training, it’s a good practice to remind drivers to slow down around curves, and that the posted speed limits for curves are meant for automobiles, not top-heavy garbage trucks.
Another enhanced risk of flipping a truck occurs when the truck is being unloaded especially with transfer trailers that unload by raising one end of the trailer and waiting for the material to slide out the back end. Once again, the main concern is the changing center of gravity. Unloading a transfer trailer, roll-off box, compactor box or packer body will raise the center of gravity resulting in less stability. Stuck loads that will not slide out of the trailer or container can increase the risk of rollover.
At the transfer station or the landfill, the driver must position the truck or trailer on level ground as even a slight slope can result in a rollover. The driver must make certain that the tailgate is unlocked before the unloading process begins. The stability of the surface is another important consideration. A mushy or soft surface may result in the truck tipping especially as the weight of the load is transferred to the rear wheels during the unloading process.
Compactor and dozer operators at the landfill should be constantly evaluating the quality of the unloading area and working to ensure the unloading area at the working face of the landfill is safe.
Drivers should also maintain space between vehicles. If a truck or trailer does roll, everyone around vehicle is in danger. For this reason, drivers should maintain a safe space between vehicles. Equipment operators including compactor and dozer operators need to be especially careful when working around trucks and trailers that are unloading.
Mechanical, road and weather conditions can also be contributing factors to rollover accidents.
Drivers are required to perform pre-trip and post trip inspections of their vehicles. Trucks with weak suspensions, broken springs, worn out tires and underperforming hydraulic systems should be immediately repaired. Road and weather conditions can also impact truck and trailer stability. Icy, snow packed and slippery road conditions may cause a truck to slide or skid which can add to the potential for a rollover accident. High winds can also be a problem especially at a landfill when tip trailers are raised in the air during the unloading process. Loads that are frozen inside of a compactor or in a transfer trailer can also increase the risk of a rollover as the trailer or compactor is elevated for dumping.
A rollover of a garbage truck or transfer trailer can result in serious injury to employees and will cause significant damage to the vehicle. Rollover accidents are avoidable. Drivers should slow down when turning or maneuvering through curves. Drivers should pay particular attention to roadway and shoulder conditions and make sure that tires are properly inflated. When unloading trucks make sure the ground is level and solid especially when at a landfill’s active unloading area. Always be alert and make sure there is ample space between vehicles in the event a truck does rollover.
Next month’s safety tip will discuss investigations and root cause analysis that should be completed following an accident or injury.
Will Flower is the Vice President of Corporate and Public Affairs at Winters Bros. Waste Systems. Will has 32 years of experience in the area of solid waste management and environmental protection. He has held operational and executive leadership positions at the Director’s Office of the Illinois Environmental Protection Agency, Waste Management, Inc., Republic Services. Inc. and Green Stream Recycling.
Share your safety tip. Submit your suggestions to Will Flower at [email protected].