Jackknife Truck Accident Cases
When a semi-truck jackknifes, the trailer swings violently outward, blocking multiple lanes and striking everything in its path. These accidents are almost always preventable — and almost always caused by driver or carrier negligence.
What Is a Jackknife Accident?
A jackknife accident occurs when a truck's cab and trailer fold toward each other, forming a shape resembling a folding jackknife. The trailer swings outward at an angle — often 90 degrees or more — sweeping across adjacent lanes.
The danger is extreme: the swinging trailer can crush passenger vehicles, block entire highways, and trigger multi-vehicle pileups. A jackknifing truck can easily kill multiple people in seconds.
Despite being well-understood, jackknife accidents continue to happen because of driver error, mechanical failure, and unrealistic carrier pressure to meet delivery schedules.
Common Causes of Jackknife Accidents
- → Sudden hard braking — Especially when the trailer is empty or lightly loaded, locking the drive axle brakes
- → Brake system failures — Improperly adjusted, poorly maintained, or defective air brakes
- → Speeding in curves — Excessive speed on curves or ramps causes the trailer to swing
- → Slippery road conditions — Ice, rain, or snow combined with a driver who doesn't slow down appropriately
- → Improper braking technique — Inexperienced drivers who don't know how to brake a loaded trailer safely
- → Unbalanced or shifting cargo — Improperly secured loads that shift during transit
- → Tire blowouts — Sudden loss of control from a blown tire on the drive axle
FMCSA Regulations and Jackknife Prevention
Federal regulations require commercial trucks to be equipped with anti-lock braking systems (ABS) — which, when properly maintained, significantly reduce jackknife risk. Violations that may apply to jackknife cases include:
- → Failure to maintain brake systems in proper working condition (49 CFR Part 393)
- → Exceeding maximum speed limits for conditions
- → Operating with improperly adjusted brakes
- → Failure to conduct required pre-trip brake inspections
- → Hours-of-service violations causing driver fatigue
Who Is Liable in a Jackknife Accident?
Multiple parties may share liability in jackknife accidents:
- The driver — For improper braking, speeding, or negligent operation
- The trucking company — For hiring unqualified drivers, poor maintenance practices, or pressuring drivers to speed
- The maintenance company — If third-party mechanics failed to properly service the brakes
- The brake manufacturer — If an ABS system or other brake component was defectively designed or manufactured
- The cargo loader — If improperly secured cargo contributed to the loss of control
Typical Injuries in Jackknife Accidents
The sweeping motion of a jackknifing trailer often causes crushing injuries from impact forces that far exceed typical car crashes:
- Traumatic brain injury (TBI)
- Spinal cord injuries and paralysis
- Multiple fractured bones
- Internal organ damage
- Severe burns from fuel spills and fires
- Crush injuries and amputations
- Death
Critical Evidence
Brake inspection records, maintenance logs, and ELD data must be preserved immediately after a jackknife accident. An attorney can issue a litigation hold letter.