Jackknife Accidents

Some of the most dramatic types of accidents on the road are those that involve a jackknifed tractor-trailer. A tractor-trailer’s long length and often heavy weight make it a significant danger to other vehicles on the road if the driver cannot keep the truck under control.

What is jackknifing?

If you picture what an actual jackknife looks like, it’s easy to understand how the term jackknifing got its name. Jackknifing, in the context of trucking, is when a tractor-trailer ends up folded around the point where the tractor and the trailer are connected, in a manner that is visually similar to a partially folded pocket knife.

Jackknifing happens when the tractor (truck) part of a tractor-trailer starts to skid. If the driver is unable to or fails to correct the skid in time, the trailer can push the cab from behind until it spins around facing backward and ends up hitting the trailer.

A similar incident is trailer swing or trailer slew. This is when the trailer skids, rather than the truck. Trailer swing is not nearly as dangerous as jackknifing, because as the cab continues driving, the trailer will fall back into line, although drivers must be aware that a sliding trailer can collide with other cars or stationary objects. Empty or lightly-loaded trailers are particularly prone to trailer swing, and weather conditions such as strong wind can amplify the effect.

Why is jackknifing dangerous?

The main reason that jackknifing is dangerous is the same reason that all accidents involving large and heavy vehicles like a tractor-trailer are dangerous. If a tractor-trailer collides with a smaller vehicle, the driver of the tractor-trailer will most likely be fine. On the other hand, the driver and passengers of any smaller vehicle can be horribly injured, disfigured, or killed. This is simply because of the immense size and weight difference between a tractor-trailer and a typical car.

What causes jackknifing?

Jackknifing can be caused by improper braking, equipment failure, or dangerous road conditions such as ice and snow. In some cases, a driver may attempt to deliberately cause the vehicle to jackknife as a means of stopping if the brakes have failed.

The main cause of jackknifing is a loss of traction on a truck’s tires. This lack of traction can be caused by improper braking like slamming on the brakes, which can cause them to lock and make the tires start to skid. The other major cause of loss of traction is slick roads, typically caused by weather like rain, ice, and snow. A wet or icy surface makes it harder to stop, slow down, or turn.

How to Prevent Jackknifing

Jackknifing of tractor-trailers is preventable. Tractor-trailer drivers need to maintain reasonable speeds and following distances while taking into consideration the road and weather conditions. Heavier loads provide more traction than light loads or empty trailers, so drivers need to be extra careful when hauling a light load. Drivers must brake properly, using even and steady pressure to avoid locking the brakes. They can also prevent jackknifing by braking slowly and gradually, as slamming on the brakes can cause a jackknife. Drivers should maintain reasonably slow speeds, particularly in wet or icy weather. They should keep a generous following distance to avoid having to brake suddenly, and they should try to avoid having to brake on a curve. The truck and trailer should be properly maintained. A major reduction in heavy vehicle accidents resulted from the introduction of anti-lock brakes.