How to Avoid Jackknifing

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Jackknifing occurs when the trailer of a big rig or other articulated vehicle loses traction and skids sideways, forming an L or V shape with the tow vehicle. Here is an explanation of how jackknifing occurs and how to prevent it.

Steps

How Jackknifing Occurs

1. 1
   

   All is well. Trailer (B) follows tow vehicle (A).
   The vehicle is in motion on a straight course. The trailer (due to unbalanced loading, wind conditions, or worn tires) has a slight natural swing side to side.

   
   
2. 2
   

   Tow vehicle (A) applies brakes. Trailer (B) begins to swing sideways.
   The driver applies excessive brakes or turns too sharply. The trailer loses traction and begins to swing out.
3. 3
   

   Trailer (B) passes tow vehicle (A). Chances of recovery are very low.
   The trailer swings around, passing tow vehicle and sending both out of control.

Steps to Prevent Jackknifing

1. 1
   Watch for trailer swing, especially when braking, turning, and changing lanes. By keeping close tabs on the trailer, it may be possible to recognize and prevent jackknifing before it actually happens.
2. 2
   Keep both vehicle and trailer properly maintained. Worn-out tires and bad suspension components increase the risk of losing control.
3. 3
   Follow the manufacturer's recommendations for loading capacity of trailer and tow vehicle. Never drive with an overloaded or unbalanced trailer.
4. 4
   Be wary of light loads. In many cases, the trailer involved in a jackknifing incident was in fact empty.^[1] The vehicle and trailer brakes are designed for a full load, and are far too potent for an underweight trailer. When strong brakes are applied, the lighter trailer locks up and thus only needs a small input to begin skidding sideways.
5. 5
   Invest in anti-jackknife systems for your tow vehicle and trailer. Modern antilock trailer braking systems can sense tire skid and automatically adjust braking force to prevent lockup.

   
   

Warnings

• Do not drive with a trailer until you become comfortable handling it in a controlled situation.
• Technologies such as antilock brakes can reduce the chances of jackknife, but no one thing will prevent all cases of jackknife. You as the driver must be aware of your surroundings and the condition of your vehicle.
• Speed kills. If you feel the conditions are unsafe to operate the vehicle, find an area to pull over and wait for conditions to improve. If you must continue, do so at a lower speed with your hazard flashers on to maintain stability.

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