During a CMV rollover, which part of the vehicle typically rolls first?

In a CMV (Commercial Motor Vehicle) rollover, it is generally the trailer that rolls first. This phenomenon occurs due to the design and weight distribution in typical truck and trailer configurations. When a CMV is subjected to sudden steering actions or is traveling too fast around a corner, the trailer, being longer and trailing behind the cab, is often the first to reach a critical angle that leads to a loss of stability.

As the cab begins to lean during the maneuver, the trailer may also begin to shift laterally. Since the center of gravity can be higher in trailers and often further behind the front axle, it makes them more prone to tipping as they encounter forces that exceed their stabilizing abilities. This tipping can initiate a chain reaction whereby the trailer rolls over, which can subsequently affect the cab.

Understanding this mechanism is crucial for drivers to maintain control and prevent such incidents by maintaining appropriate speeds and being cautious during turns or sudden maneuvers.