CDL Prep: All You Need to Know About Jackknife

While no one wants to be in a car accident, some accidents are more terrifying than others. Imagine driving down the highway and seeing an 18-wheel semi-truck lose control and its trailer begin to swing to one side. That's what nightmares are made of, and it's what jackknifing is.

While truck accidents are among the most dangerous on the road, a jackknife accident is one of the deadliest scenarios. Here's what you need to know about jackknifing, how to correct it, and how to prevent it.

What is a Jackknife Accident?

A jackknife crash is a type of truck accident in which the truck skids, loses control, and the trailer spins towards the cab and collides with it. This usually results in a devastating crash that kills the truck driver and other road users.

What Causes A Truck to Jackknife?

A jackknife accident usually occurs when a truck driver accelerates too quickly while turning, causing the truck to skid. As a result, the trailer deviates from its intended path and swings in an L or V shape towards the cabin. The name comes from the fact that it resembles a knife with a blade that folds into the handle.

Figure 01. 4 Different causes that lead to Jackknifing on the roadway.

How to Handle A Jackknife Skid?

Step 1: Straighten Your Unit 

Get your tractor-trailer straight immediately when you start to jackknife. Stay calm, and don’t overcorrect.

Step 2: Steer in The Direction of The Skid

If your trailer is kicked out to the passenger side, steer in the direction of the skid on the same side (to the right). It is critical to steer slowly toward the skid.

Do not force the steering wheel into a skid, and do not overcorrect. This will assist in counteracting the sliding movement and straightening the truck and trailer on the road.

Step 3: Release the pedals. 

Take your feet completely off all the pedals, including the clutch, fuel, and brake. 

Step 4: Concentrate

Pay close attention to straightening your tractor-trailer. Concentrate on steering to straighten. 

Step 5: Slow down 

Slow the truck down by using your jake brake, but you can use anything you are most comfortable with. Jake brake has three settings, it is possible to use it on a lower set if the roads are excessively slippery, so it will gradually turn off the engine. 

Step 6: Use Fuel Pedal 

Gently feather the fuel pedal. However, you shouldn't do this until you take control of the truck. 

Step 7: Keep going.

 When you feel you have regained control of the truck/trailer, gently ease the truck and trailer to the side of the road.

How to Prevent Jackknives?

Avoiding a jackknife accident is the responsibility of everyone, especially truck drivers. If you work as a commercial trucker, there is no guarantee that you received additional training on avoiding jackknife accidents beyond what was required for your CDL. We want to provide a quick jackknife-avoiding instruction that every trucker should know.

• Keep an eye on your mirrors to see if your trailer is swinging or swaying. To stop the trailer's erratic movements, carefully adjust your speed or steering direction.
• Note that an empty trailer is lighter and thus more likely to lose contact with the ground while moving and, therefore, begin to jackknife.
• Brake before entering a turn when rounding a corner. Smaller cars can brake or accelerate while turning, which can be dangerous for overload trucks. You should only brake when driving straight.
• Avoid slamming on the brakes when your trailer begins to swing widely. If it is safe, take your foot completely off the brakes. 
• Trailer sway can sometimes be corrected by gradually increasing your speed, increasing your tractor's pull strength, and straightening the trailer. Increasing speed will usually not help if the tractor or caravan is shaking or swaying.

The most effective way to deal with jackknifing is to avoid it first! Nothing prevents this situation more effectively than being extra careful and cautious while driving. Keep in mind that no one got into a jackknife accident by driving too slowly.

Jackknifing can be a frightening and dangerous situation. But if you follow these common-sense suggestions, you can avoid them.

See your state CDL Handbook And Helpful Truck Driver Resources to take the first step of becoming a Commercial Truck Driver.

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