Backing & Maneuvering · Driver Training VideoJackknife Avoidance

A jackknife happens when the tractor and trailer fold toward each other instead of staying in line. It happens fast, and once the trailer swings out far enough, most drivers can't recover it.

Look at when it happens

Wet roads. Ice and snow. Loose gravel. Downhill grades. And the moment most drivers don't expect — an empty or lightly loaded trailer. Less weight over the axles means less traction, and a bouncing empty trailer breaks loose easier than a loaded one.

The trigger is almost always the same: too much speed for the surface, followed by hard braking or a sharp steering correction. Hit the brakes hard on ice and the wheels lock — the drive tires, the trailer tandems, or both. The rig stops tracking, and the trailer swings.

Here's what actually prevents it

Slow down before the curve, the ramp, or the bad weather — not during it. Brake early, brake light, and brake in a straight line. Never brake hard and turn the wheel at the same time — that combination is what breaks the trailer loose.

If your truck has ABS, use it — it lets you keep steering while you slow down, but it will not save you from a bad speed decision. If it doesn't have ABS, controlled stab braking — brake, release the instant you feel lockup, reapply — is still the right call.

Your company standard: match your speed to the road, not the posted limit. Add extra following distance in rain, snow, or on grades. Come off the throttle early on downhill sections and ramps, before you need the brakes at all.

A jackknife is rarely one bad moment — it's a string of small decisions that ran out of room. Keep your speed matched to the conditions, keep your inputs smooth, and you'll never find out how fast that trailer can come around on you.