When is jack-knifing most likely to occur?

Jack-knifing is most likely to occur when trying to reduce speed sharply while travelling downhill. This situation puts significant stress on the vehicle's trailer and can cause it to pivot or swing out, creating a dangerous angle between the truck and the trailer.

When going downhill, the momentum of the vehicle increases, making it more challenging to control weight distribution, especially if brakes are applied suddenly or too hard. This can lead to the rear of the trailer swinging outward, resulting in a jack-knife situation.

While sharp turns, wet roads, and reversing can all create challenging situations for drivers, the combination of speed, weight, and steep gradients during downhill travel makes it particularly conducive to jack-knifing.