A jackknife will occur when the angle between the tractor and trailer reaches what percentage?

A jackknife situation typically occurs when the angle between the tractor and trailer reaches about 10 degrees. At this angle, the trailer can begin to pivot toward the side of the tractor, resulting in a loss of control. The dynamic forces acting on the vehicle can cause the trailer to swing out, leading to a dangerous situation where the trailer and tractor are not aligned and can potentially collide, which can overturn the vehicle or cause it to skid uncontrollably. Understanding this threshold is crucial for drivers to maintain control, especially during turns and when sudden braking is involved. It emphasizes the importance of proper speed management and maintaining awareness of the vehicle's dynamics while driving.