Which trailer is most at risk of turning over when turning suddenly while pulling doubles?

When evaluating the risk of a trailer turning over during a sudden turn while pulling doubles, it's important to consider the dynamics and balance of the entire vehicle combination. The last trailer is most at risk because it is furthest from the pivot point created by the tractor. When making a sudden turn, the last trailer experiences a wider arc compared to the front trailers, which can lead to greater lateral forces acting upon it.

Additionally, the weight distribution and the positioning of the trailers contribute to this risk. As the last trailer swings outwards during the turn, it can become unstable, especially if the load is heavy or not properly secured. This can cause a rollover situation if the forces exceed the trailer’s tipping point.

In contrast, the first and second trailers are closer to the tractor, which helps them maintain stability and reduces the likelihood of a rollover. Therefore, understanding the physics of turning and the positioning of the trailers explains why the last trailer is particularly vulnerable to turning over in sudden maneuvers.