Do you know how to handle a jackknife? This has nothing to do with a pocket knife. We're talking about that frightening phenomenon when a vehicle pulling a trailer goes into a skid, the trailer swings out and the vehicle folds back to meet it.
Jackknifing is most likely when the drive wheels are locked-on reaching a slick spot, while the front wheels and the trailer wheels keep rolling. Usually it occurs on slippery roads when a driver takes a curve too fast, or when cresting a hill too fast and finds a stalled vehicle or other obstacle and must swerve or make a panic stop. It can happen too, with too much speed on a downgrade just before a turn or stop.
If you should ever find yourself in a skid and beginning to jackknife, steer in the direction of the jackknife very carefully. You must rely completely on steering—but don't over steer. Lay off the brakes and accelerator. Directional control is best when all wheels are rolling. When the pavement is made slick by ice, snow or rain, the experienced driver knows what can happen. They avoid jackknifing by adjusting their speed to conditions—especially on hills and curves, or whenever the traffic situation suggests that a quick stop may be necessary.