What Causes a Semi-Truck to Jackknife?

by William Mattar | July 30th, 2020

Semi-trucks can be some of the largest, heaviest vehicles on the road.  When they crash, the consequences can be terrifying, causing severe injuries and fatalities. One potential cause of a truck accident is when a truck “jackknifes.” What causes a truck to jackknife, and why is it so dangerous? Read on, and we will explain.

Many people may know what a jackknifed tractor-trailer looks like, sprawled across the highway. These types of accidents occur when the cab and trailer go in different directions. In some cases, the truck overturns completely. Jackknife accidents can happen in an instant, and if you happen to be behind the truck when it happens, you could find yourself in a potentially dangerous situation.


There are a variety of reasons a jackknife accident can occur, including improper brake maintenance. When the brakes on a semi-truck are not working properly, it may cause the axles to lock-up. In these instances, the truck is dragging the trailer with locked brakes, which can push the trailer out to the side of the cab, causing the truck to “jackknife.”


Speeding can also lead to a jackknife accident. Semi-trucks can sometimes weigh up to 80,000 pounds when fully loaded. Sudden braking can be too much for a loaded trailer to handle, leading to the truck stopping at a different rate of speed than the trailer.

Road Conditions

Slippery roads, caused by rain or snow, can also cause trucks to jackknife. In these conditions, trucks can lose traction and slide, sometimes resulting in a jackknife accident. Avoiding debris in the road or other road conditions, like potholes, can also cause a semi-truck to jackknife.

An inexperienced driver can be a contributing factor to a jackknife accident. For instance, a driver who is unable to properly handle the truck in unexpected or challenging situations can be at increased risk of causing the truck to jackknife. The same may hold true for a fatigued driver. Adequate training and rest are vital for the drivers of semi-trucks. Additionally, impaired driving, whether by drugs or alcohol, can increase the risk of semi-truck accidents.


What’s in the trailer, and how it’s packed can also affect whether or not a truck will have a tendency to jackknife. Improperly secured cargo can force the trailer to move around, leading to an accident. Proper weight distribution can also impact how the trailer responds.

Jackknife accidents often involve multiple vehicles. If you have been injured in an accident with a truck, you may want to consider seeking medical treatment immediately after the crash. If you have been injured, you may want to contact an experienced personal injury attorney to review your case and help you receive maximum compensation. The cause of the accident needs to be determined, and a complete review of the accident can help determine how it happened and whether the truck driver was negligent. There are a number of ways in which a trucking company could be negligent in the case of a jackknife accident, from not maintaining brakes to providing inadequate training. Additionally, the driver may be negligent if his or her actions led to the accident.

Need a Truck Accident Lawyer?

An experienced truck accident lawyer like those at William Mattar law offices know what to look for when reviewing your case. Contact William Mattar law offices 24/7 for a free consultation. 844-444-4444.