In the poultry business it seems that single-vehicle rollovers happen every day. Rollovers are common due to the design of feed and live haul trucks and trailers, the roads on which we drive and often, driver error.

Preventing rollovers begins with understanding their cause. So we start with the question, "What causes a rollover accident?" Often the answer is "driving too fast for the road and weather conditions." We need to go beyond that general answer and look closely at many of the factors that impact the likelihood of a rollover accident to increase the awareness of both driver and trucking supervisor, leading to safer fleet operations.

Let's look at three issues that affect the potential for a rollover: vehicle design and performance, road design and human factors. You may be surprised to learn how easy it is to rollover.

Feed haul and livehaul units

We'll begin by looking at the design of feed haul and live haul units.

There are many factors with the design and performance of vehicles that may contribute to a rollover accident including:

  • A higher center of gravity than most other vehicles.
  • The length, width and weight of the tractor-trailer unit.
  • A flexible trailer frame that allows excessive torque in the trailer.
  • The trailer may not follow the track of the tractor when turning at higher speeds.

While all these factors may contribute to an accident, drivers first need to understand that a high center of gravity creates a more unstable object. For vehicles, a high center of gravity will allow the unit to lean when negotiating a turn.


With an articulated vehicle a tractor and a trailer the driver may not feel the shift in the trailer's center of gravity, signaling the beginning of the rollover until it is too late to react. The trailer's higher center of gravity may allow the trailer's inside wheels to lift off the ground while the flexibility of the trailer frame and the pivot point between the tractor and the trailer allow the tractor's wheels to stay on the ground. The driver's first indication is when the trailer has reached the point of no return and starts to pull the tractor over.

There are a number of vehicle condition issues that should be considered. Certainly poor brake performance, damaged suspension, under-inflated tires, improperly secured cargo, and other issues may contribute to a rollover. These types of factors can be eliminated with an adequate pre-trip inspection.

Highway factors

Highway factors include: sharp or improperly banked curves, steep downhill grades, soft shoulders, berms, curbs and narrow driveway entrances or exits.

It is important to survey and identify high-risk sections of regularly traveled routes. Routes to regular destinations such as grow-out farms should be surveyed in advance to identify and avoid high-risk areas. Drivers should proceed cautiously until they know and are comfortable with the route.

The driver

Other than conducting a thorough pre-trip inspection, the driver has little control over the unit or the road conditions. However, the driver does have complete control over his or her actions. Unsafe behavior includes speeding, reckless operation, complacency, fatigue, driving under the influence and various physical and mental conditions.

The bottom line is simple: Rollovers are preventable and unacceptable.