What is the term for when a trailer is travelling faster than the drawing vehicle?

The situation where a trailer travels faster than the drawing vehicle is known as jack-knifing. This occurs primarily with articulated vehicles (like trucks with trailers), and it typically happens when the trailer swings out to the side due to a loss of control or slippery conditions. If the trailer moves ahead of the drawing vehicle, it angles back towards the tractor unit, creating a sharp ‘V’ shape, which can lead to a loss of control and significant danger on the road.

While oversteering refers to the handling dynamics where the rear end of a vehicle slides out during a turn and skidding refers to a loss of traction, these terms do not specifically describe the particular issue of a trailer exceeding the speed of the drawing vehicle. Rear-ending, which involves one vehicle colliding into the back of another, does not apply to the dynamics of trailer movement relative to its towing vehicle. Jack-knifing, therefore, aptly describes the unique and hazardous situation presented in this question.