What does the term "jackknife" refer to in truck driving?

The term "jackknife" in truck driving refers to the scenario when a trailer swings out, resulting in the truck and trailer forming a V shape. This typically occurs during sudden braking or sharp turns when the trailer skids out of control relative to the towing vehicle. Such a situation can be very dangerous as it significantly reduces the driver's ability to steer and control the vehicle, potentially leading to collisions or accidents.

Understanding the mechanics of a jackknife situation is crucial for drivers, as it highlights the importance of managing speed, maintaining safe following distances, and being cautious during inclement weather or when making sharp turns. Recognizing the signs that could lead to a jackknife will allow drivers to take preventive measures to avoid this hazardous situation.