Skid Control, Jackknifing, and Emergency Maneuvers
Types of Skids
A drive-wheel skid happens when the rear tires lose traction, often from too much throttle or braking. A steer-wheel skid happens when the front tires lose traction, and steering control is lost. A trailer skid happens when the trailer wheels lock or lose traction, and the trailer swings out. Recognize which skid you are in before reacting, because the correction differs.
Jackknifing
A jackknife is when the tractor and trailer fold toward each other. It is most common when the drive wheels lock during hard braking on a slippery surface, or when the trailer swings out. To prevent it, brake smoothly, avoid locking the drive wheels, and keep the trailer behind you. If a jackknife begins, release the brakes to let the wheels roll and regain traction, and steer to follow the trailer.
Emergency Maneuvers
If a tire blows, hold the wheel firmly, avoid hard braking, and slow gradually. If the brakes fail, downshift and use engine braking, and look for an escape route. If you must stop quickly, brake firmly but progressively, and steer around the hazard if there is room. Traps: questions that suggest slamming the brakes during a skid, or that say you should steer away from the trailer during a jackknife.
Rule of Thumb
"Release to recover." When wheels are locked, releasing the brake lets them roll and regain grip.