David J. Muñoz | March 12, 2026 | Truck Accidents

Large commercial trucks are essential to the American economy, transporting goods across the country every day. However, because of their size and weight, these vehicles can cause devastating accidents when something goes wrong. One of the most dangerous types of crashes involving semi-trucks is a jackknife accident. These accidents often lead to severe injuries, major property damage, and even fatalities.

Understanding what causes jackknife truck accidents and the types of injuries they can produce can help drivers remain aware of potential dangers on the road. It can also help accident victims recognize when negligence may have played a role in a serious crash.

What Is a Jackknife Truck Accident?

A jackknife truck accident occurs when a tractor-trailer folds at the connection between the tractor and the trailer, forming an angle that resembles a folding pocketknife. Instead of moving in a straight line, the trailer swings outward while the cab continues forward, creating a dangerous sideways position across lanes of traffic.

Once a truck begins to jackknife, the driver often loses control of the vehicle. The trailer may block multiple lanes of traffic, collide with nearby vehicles, or trigger chain-reaction crashes involving several cars. Because fully loaded semi-trucks can weigh up to 80,000 pounds, the force of these accidents can be catastrophic.

Common Causes of Jackknife Truck Accidents

Several factors can lead to a jackknife accident, often involving driver actions, road conditions, or vehicle issues. 

Common causes include:

• Sudden or Hard Braking: Slamming on the brakes can cause the trailer to move faster than the cab, making it swing outward and fold toward the truck.
• Slippery Road Conditions: Rain, ice, oil, or loose gravel can reduce tire traction and make it harder for drivers to control the truck.
• Speeding or Driving Too Fast for Conditions: High speeds—especially on curves or downhill roads—can cause the trailer to swing out during braking or sharp turns.
• Improperly Loaded Cargo: Uneven or unsecured cargo can shift inside the trailer, affecting the truck’s balance and stability.
• Driver Fatigue: Tired drivers may have slower reaction times and impaired judgment, increasing the risk of losing control.
• Mechanical Failures: Problems with brakes, tires, or trailer connections can prevent the truck from responding properly when slowing or maneuvering.

Because multiple factors can contribute to a jackknife accident, identifying the underlying cause is often critical for understanding how the crash occurred and who may be responsible.

Common Injuries Caused by Jackknife Truck Accidents

Some of the most common injuries in these crashes include:

• Traumatic Brain Injuries: Head trauma is one of the most serious outcomes of truck accidents.
• Spinal Cord Injuries: The powerful impact of a truck collision can cause damage to the spinal cord. Victims may suffer herniated discs, fractured vertebrae, or nerve damage.
• Broken Bones: Jackknife truck accidents often produce high-impact collisions that result in broken bones. Arms, legs, ribs, and hips are particularly vulnerable during these crashes.
• Internal Injuries: Blunt force trauma during a truck accident can damage internal organs such as the liver, spleen, lungs, or kidneys. 
• Severe Lacerations and Burns: Debris from a truck accident can cause deep cuts and lacerations. In some cases, fires or explosions may occur if fuel tanks rupture during the crash.
• Emotional Trauma: The effects of a jackknife truck accident are not always physical. Many victims experience emotional and psychological trauma after a serious crash.

Because these injuries can be severe, anyone involved in a jackknife truck accident should seek medical attention as soon as possible.

Who May Be Liable for a Jackknife Truck Accident?

Determining liability in a jackknife accident can be complicated. Multiple parties may be responsible depending on the circumstances of the crash.

Potentially liable parties may include:

• The truck driver
• The trucking company
• Cargo loading companies
• Truck maintenance providers
• Vehicle or parts manufacturers

For example, if a trucking company failed to maintain the vehicle properly or pressured a driver to exceed safe driving hours, it may share responsibility for the accident.

What to Do After a Jackknife Truck Accident

Taking the right steps after a jackknife truck accident can help protect both your health and your legal rights. 

If you are involved in a crash, consider the following steps:

• Seek medical attention immediately: Some injuries, such as concussions or internal bleeding, may not show symptoms right away.
• Call law enforcement: A police report can document the accident and may be important for insurance and legal claims.
• Document the scene: If it is safe, take photos of the vehicles, road conditions, and any visible injuries.
• Gather witness information: Names and contact details from witnesses may help clarify how the accident occurred.
• Avoid discussing fault: Do not admit blame or speculate about the cause of the accident at the scene.

Taking these steps can help ensure the accident is properly documented and that important evidence is preserved for any potential claim.

Seeking Legal Help After a Jackknife Truck Accident

Jackknife truck accidents can cause life-changing injuries and significant financial losses. Medical bills, lost wages, and long-term rehabilitation costs can quickly become overwhelming for victims and their families.

If negligence contributed to the crash, injured individuals may be entitled to seek compensation for their damages. A personal injury attorney can investigate the accident, gather evidence, and help determine who may be responsible.

Contact a San Diego Truck Accident Lawyer at Mission Personal Injury Lawyers for a Free Consultation 

Jackknife truck accidents are among the most dangerous types of crashes involving large commercial vehicles and can cause severe, life-altering injuries such as traumatic brain injuries, spinal cord damage, and broken bones.

If you’ve been injured in San Diego or Chula Vista, please call Mission Personal Injury Lawyers for a free case evaluation with a personal injury lawyer or contact us online.

We proudly serve San Diego County and throughout California.

Mission Personal Injury Lawyers – San Diego Office
3666 Fourth Ave, San Diego, CA 92103
(619) 777-5555

Mission Personal Injury Lawyers – Chula Vista Office
690 Otay Lakes Rd #130, Chula Vista, CA 91910
(619) 722-3032

We also serve the state of Texas. For legal assistance, contact our personal injury law office in El Paso today.
Mission Personal Injury Lawyers – El Paso Office
201 E Main Suite 106, El Paso, Texas 79901
(915) 591-1000