Common Causes of Big Rig Truck Accidents

Understanding why a big rig crash happened is the foundation of every truck accident claim. The cause determines who can be held liable — the driver, the trucking company, a maintenance contractor, or a manufacturer — and what evidence a big rig truck accident lawyer needs to preserve.

Federal crash data from the FMCSA and NHTSA consistently shows that most serious truck accidents trace back to a handful of preventable failures. The pages below break down each major cause, the federal rules involved, and how it affects liability.

The ten most common causes

• Driver fatigue — hours-of-service violations and drowsy driving remain a leading factor in fatal large-truck crashes.
• Jackknife accidents — the trailer swings out past the cab, often sweeping across multiple lanes of traffic.
• Underride accidents — a passenger vehicle slides beneath the trailer; among the deadliest crash types on the road.
• Rollover accidents — a high center of gravity and speed on curves can tip a loaded trailer.
• Blind spot (No-Zone) accidents — large blind spots on all four sides hide vehicles during lane changes.
• Wide turn accidents — the "squeeze play" traps vehicles beside a turning trailer.
• Cargo shift & overloading — unsecured or unbalanced freight destabilizes the trailer mid-drive.
• Impaired driving (DUI) — commercial drivers face a stricter 0.04% BAC limit and mandatory testing.
• Brake failure — skipped inspections and deferred maintenance frequently point to carrier negligence.
• Tire blowouts — worn, defective, or under-inflated tires on an 80,000-pound rig can cause total loss of control.

Why the cause of the crash matters legally

In an ordinary car accident, the question is usually which driver was careless. In a commercial trucking case, the cause opens the door to different defendants and different evidence:

Much of this evidence is controlled by the trucking company and can be lost or overwritten within weeks. That's why the first step in a serious case is a preservation (spoliation) letter — something an attorney sends immediately. Learn more about FMCSA regulations and truck accident evidence, who can be held liable, and common truck accident injuries.