Truck rollover crashes

Center of gravity and speed

The Oregon commercial driver manual explains that a higher center of gravity increases rollover risk and advises slowing before curves. It also describes rearward amplification, sometimes called the crack-the-whip effect, in combinations with multiple trailers. A speed that appears ordinary on a straight road may therefore be unsuitable for a curve or abrupt maneuver involving a particular vehicle and load.^[1]

Cargo-tank considerations

FMCSA provides a separate cargo-tank rollover prevention program addressing driver error, vehicle design and performance, and load effects. Tank vehicles should not be treated as interchangeable with dry vans. The liquid load and vehicle configuration belong in the analysis along with the route and driver actions. Guidance about one tank operation does not establish the condition of another vehicle.^[2]

Avoiding a one-cause label

The combination-vehicle manual connects rollover prevention with keeping cargo low and centered, as well as avoiding abrupt steering. These are distinct questions: a driver may need an evasive maneuver, and the load may affect how the vehicle responds. Investigation should test the proposed mechanism rather than assume a load was improperly secured solely because the trailer overturned. Cargo-securement rules provide a separate set of requirements.^[1]

Related entries

• Jackknife crashes How tractor and trailer skids differ and why a folded combination does not identify the initiating event.
• Cargo loading and securement Federal performance, equipment and driver-check requirements, and why loading responsibility needs its own analysis.
• Engine control modules and electronic crash evidence Distinguishing heavy-truck engine data, event recorders and ELDs, with attention to device-specific limits.
• Truck driver fatigue The federal fatigue prohibition, its relationship to driving limits and the limits of log-based conclusions.