How Defective Truck Parts Cause Accidents
FMCSA
Federal Motor Carrier Safety Administration. The federal agency that regulates commercial vehicles, sets safety standards, and enforces trucking rules including hours of service, vehicle inspections, and driver qualifications.
Equipment failures are twice as likely on commercial trucks as on passenger vehicles, according to FMCSA data. An 18-wheeler travels hundreds of thousands of miles annually under extreme load and stress. Parts wear faster. Maintenance lapses have larger consequences.
FMCSA Part 393 sets the minimum equipment standards every commercial motor vehicle must meet. A truck operating in violation of Part 393 standards is operating illegally. That violation is evidence of negligence in any personal injury claim.
Defects come from multiple sources. A part may have an inherent design flaw. A unit may have been manufactured out of spec. A recall may have been ignored. A maintenance contractor may have missed a failing component during inspection. Not all equipment failures are visible after a crash. The debris gets cleared. The truck gets towed. Parts get replaced. Identifying defective equipment requires investigation before that evidence disappears.
Louisiana recorded 811 motor vehicle fatalities in 2023, with 413 on roads above 50 mph where loaded trucks regularly operate, according to IIHS state fatality data. The state’s fatality rate of 21 deaths per 100,000 people is well above the national average of 12.9. LSU’s CARTS data shows an injury crash occurring in Louisiana every 15 minutes. These numbers reflect a state where dangerous roads and heavy commercial traffic intersect constantly.
Tire Failures on 18-Wheelers
Tires are the most frequently failing component on tractor-trailers. The FMCSA and NHTSA both track this. It makes sense. Tractor-trailer tires roll under loads of 34,000 lbs per axle group on frequently rough road surfaces. Highway speeds generate significant heat in the tire casing.
That said, road wear is not always the cause. Many tire failures trace directly to the manufacturer. Tread separation, bead failure, sidewall blowouts, and improper load ratings are all manufacturing or design issues. A tire with a structural defect will fail regardless of how well the driver maintains it. When a blowout happens at highway speed, the driver loses directional control and the truck can cross into oncoming lanes or roll.
Strict Liability
A legal standard where the manufacturer is liable for a defective product without the injured person having to prove the manufacturer was negligent. You prove the defect existed and caused the injury.
Strict Liability applies to tire manufacturers when the defect made the product unreasonably dangerous. This matters because proving negligence against a manufacturer is difficult. Proving a defect existed and caused the crash is the more direct path.
When NHTSA issues a recall for a defective tire model, a carrier that ignores the recall and keeps those tires in service is independently negligent. That is a separate theory of liability from the product defect claim itself. A tire defect case can name the tire manufacturer, the trucking company, and the maintenance contractor all in the same lawsuit.
Brake System Failures
An 80,000-lb truck traveling at 65 mph requires roughly 525 feet to stop under normal conditions. Brakes are the second most common failure point on commercial trucks. When they fail, that stopping distance becomes irrelevant.
FMCSA
Federal Motor Carrier Safety Administration.
Brake failures come from both the manufacturing side and the maintenance side. A defective ABS module, a design flaw in the air brake valve, or improperly rated brake lining are manufacturer issues. Worn brake lining that was not replaced on schedule, an air leak that was missed during inspection, or improper brake adjustment after service are maintenance failures. FMCSA requires pre-trip and post-trip brake inspections. A carrier’s failure to document those inspections is a logged violation. Those records are discoverable.
The key question in a brake failure case is who is responsible. If the lining was defective from the factory, the manufacturer is the primary defendant. If the lining wore down and was never replaced, the trucking company or its maintenance contractor may be primarily at fault. In many cases, both apply. Identifying the correct defendants early matters because it determines the insurance policies in play.
Steering, Coupling, and Other High-Risk Failures
Beyond tires and brakes, several other components fail on commercial trucks with serious consequences.
Steering System Defects
Steering failures typically involve tie rod ends, power steering pumps, or kingpin assemblies. A worn or defective tie rod can snap without warning. A failing kingpin allows excessive play in the steer axle. These failures cause sudden, unrecoverable loss of directional control. There is no warning signal. The driver cannot compensate.
FMCSA
Federal Motor Carrier Safety Administration.
FMCSA Part 393.209 governs steering wheel systems (steering lash, column, gear box, power steering). A truck with excessive steering play or worn components is out of compliance. If a pre-trip inspection should have caught the defect and did not, the carrier has a maintenance liability problem on top of whatever product defect existed.
Coupling, Hitch, and Lighting Failures
Trailer separation at highway speed is catastrophic for every vehicle behind the truck. FMCSA Part 393.70 governs coupling device requirements. A defective fifth wheel, worn kingpin, or improperly installed safety chain can all contribute to separation. These cases can name both the coupling manufacturer and the carrier responsible for maintenance.
Lighting defects are a different failure mode but equally dangerous. Nonfunctioning marker lights, inoperative brake lights, or missing turn signals violate FMCSA Part 393.9. A following driver who cannot see the truck’s braking response has no time to react.
ECM and ELD System Failures
ECM
Engine Control Module. The truck’s onboard computer that records pre-impact speed, braking, throttle position, and other data. Sometimes called the “black box.” Data can be overwritten within 30 days without a preservation demand.
ECM malfunctions are uncommon but significant. A defective ECM can send incorrect throttle signals or fail to engage safety systems. More commonly, ECM firmware bugs have caused speed control issues in specific truck models, triggering recalls.
ELD
Electronic Logging Device. A device installed in commercial trucks that automatically records driving time. Required by federal law since 2019. ELD data is key evidence in truck accident cases because it documents hours behind the wheel.
ELD failures that mask hours-of-service violations may indicate both equipment and compliance failure. A carrier running trucks with malfunctioning ELDs is operating outside federal requirements.
Product Liability Claims Against Manufacturers and Distributors
When a defective part causes your crash, the legal claim against the manufacturer is governed by the Louisiana Products Liability Act (LPLA), codified at La. R.S. 9:2800.51 through 9:2800.60. The LPLA is the exclusive remedy against a manufacturer in Louisiana.
Under the LPLA, a manufacturer is liable for damage caused by an unreasonably dangerous product. There are three theories:
Design defect: The entire product line is dangerous because of the way it was designed. If a specific tire model has an inherent tread separation risk under normal operating conditions, every tire made to that design is defective.
Manufacturing defect: This specific unit was built incorrectly. The design was acceptable but something went wrong during production. This unit deviated from the manufacturer’s own specs in a way that made it unsafe.
Failure to warn: The manufacturer knew a risk existed but failed to disclose it. This applies when the defect is not obvious and the user had no way to know the product was dangerous without a warning.
Product liability claims run parallel to negligence claims. You can sue the parts manufacturer under the LPLA and sue the trucking company for negligent maintenance in the same lawsuit. Defendants can include the parts manufacturer, the truck OEM (original equipment manufacturer), the distributor, the installation shop, and the third-party maintenance contractor.
The LPLA has specific pleading requirements and an expert disclosure timeline distinct from a standard truck negligence case.
Morris & Dewett has handled product liability claims involving defective commercial truck components alongside our Louisiana big truck injury practice. We retain engineers with commercial vehicle backgrounds when the case requires it.
Spoliation of Evidence: Preserving Defective Parts
Spoliation
The destruction or alteration of evidence after a party has notice of pending litigation. Courts can instruct juries to assume the destroyed evidence was unfavorable to the party that destroyed it.
Spoliation is one of the most important issues in any defective truck parts case.
The trucking company’s insurer will have adjusters and investigators at the scene within hours. The manufacturer may follow. Their goal is to document the scene on their terms. The defective part gets photographed, tagged as “road debris,” and potentially replaced during routine maintenance. The ECM gets connected to a company laptop and the data gets pulled. Without a preservation demand already in place, that data may be overwritten in the next 30 days.
Preservation Letter
A formal legal demand sent to the trucking company requiring them to preserve all evidence related to the crash. Stops the carrier from overwriting black box data or destroying driver logs on their normal retention schedule.
A Preservation Letter must go to the trucking company, the manufacturer, and any third-party maintenance contractor within days of the crash, not weeks. FMCSA accident record-keeping rules require carriers to retain accident-related records for one year. But that is a floor, not a ceiling, and it does not prevent replacement of defective parts before litigation is filed.
When preservation demands are ignored, courts can impose sanctions and instruct juries to infer that the destroyed evidence was unfavorable to the party that destroyed it. That instruction can be decisive. But you need the preservation demand documented and timestamped to make that argument.
Morris & Dewett sends preservation letters within 24 hours of engagement on truck accident cases. The ECM, driver logs, maintenance records, and the defective part itself get locked down before anyone can claim they were lost.
Who Is Liable When Defective Parts Cause a Crash?
In a defective truck parts case, Louisiana law can hold the parts manufacturer, the trucking company, and the maintenance contractor liable simultaneously. Each defendant’s percentage of fault is determined by the jury under Louisiana’s comparative fault system. Each defendant pays their assigned share of the damages.
Strict Liability
A legal standard where the manufacturer is liable for a defective product without the injured person having to prove the manufacturer was negligent. You prove the defect existed and caused the injury.
respondeat superior
Latin for “let the master answer.” A legal doctrine holding employers liable for negligent acts committed by employees within the scope of their employment.
The parts manufacturer bears Strict Liability under the LPLA for a defective design or manufacturing defect. The OEM can be liable if it specified or integrated the defective component. The trucking company is liable under respondeat superior for its driver’s failure to report a known defect, and independently for its own failure to maintain the vehicle. The third-party maintenance contractor is liable if improper service caused or missed the defect.
Vehicle maintenance records are critical evidence. Federal courts have held that a carrier’s failure to maintain required inspection logs supports a finding of negligence per se under FMCSA regulations. If the carrier cannot produce 90-day pre-trip inspection records for the truck, that absence speaks for itself.
Louisiana’s direct action statute, La. R.S. 22:1269, allows you to sue the trucking company’s insurer directly without first obtaining a judgment against the carrier. This matters when a carrier is undercapitalized or in bankruptcy.
East Baton Rouge Parish reported 61 fatal crashes in 2023, among the highest of any Louisiana parish, according to LSU CARTS data. High-traffic corridors with dense commercial truck activity raise the probability of encounters with poorly-maintained or defectively-equipped vehicles.
What to Do After a Truck Accident Caused by a Defective Part
The steps you take in the first hours after a crash affect your case.
Call 911. Do not move the vehicles if possible. The accident scene is evidence. Law enforcement will create an accident report that documents conditions at the time of the crash.
Photograph everything you can reach safely: the truck, the damaged component, skid marks, debris patterns, road conditions, and the positions of all vehicles. Take photographs before anything is moved. Once the scene is cleared, that evidence is gone.
Write down the truck’s DOT number, carrier name, and license plate. These are the identifiers you need to pull the carrier’s FMCSA safety record, inspection history, and prior violations. A carrier with a history of brake or tire violations is a different defendant than one with a clean record.
Get a medical evaluation even if you feel fine. Internal injuries and soft tissue damage frequently do not present symptoms immediately. A medical record dated the same day as the crash establishes a baseline that insurance carriers cannot later dispute.
Do not give a recorded statement to the trucking company or its insurer before you have spoken to an attorney. Adjusters are trained to ask questions that establish comparative fault. Your answers are permanently recorded and will be used in litigation.
Preservation Letter
A formal legal demand sent to the trucking company requiring them to preserve all evidence related to the crash.
Contact an attorney as soon as possible. The ECM data can be overwritten within 30 days. Preservation Letter needs to go out before that window closes. Every day that passes is a day the evidence degrades.
What Compensation Does Louisiana Law Allow After a Defective Parts Crash?
Louisiana law allows recovery for economic and non-economic losses in a personal injury claim.
Loss of Earning Capacity
The difference between what you could have earned over your working lifetime and what you can earn now after the injury. Calculated by a vocational expert and converted to present value by an economist.
Economic damages include past and future medical expenses, lost wages and future lost income, Loss of Earning Capacity, rehabilitation costs, and vehicle repair or replacement. These are documented losses with paper trails.
Loss of Consortium
A legal claim available to a spouse for the loss of companionship, affection, and support caused by the injured person’s condition. It is a separate damage category from the injured person’s own claims.
Non-economic damages include physical pain, mental anguish, loss of enjoyment of life, disfigurement, and Loss of Consortium. These require expert testimony and specific documentation to establish their value.
Survival Action
A claim under La. C.C. Art. 2315.1 that recovers damages for the victim’s own pain and suffering between the moment of injury and the moment of death. It is separate from the wrongful death action and can be filed alongside it.
When a crash is fatal, Louisiana law allows a wrongful death action under La. C.C. Art. 2315.2 by surviving family members and a Survival Action under La. C.C. Art. 2315.1. Both claims can be pursued simultaneously.
Comparative Fault
A legal rule that reduces your recovery by your percentage of fault. In Louisiana, if you are 51% or more at fault, you recover nothing. If you are 50% or less at fault, your damages are reduced proportionally.
Comparative Fault applies to every claim. Under La. C.C. Art. 2323 as amended by Act 15 of 2025, effective January 1, 2026, a plaintiff who is 51% or more at fault recovers nothing. Below 51%, the award is reduced proportionally. In a defective parts case, the manufacturer will argue that the driver failed to inspect the part. The trucking company will argue the manufacturer is solely responsible. These fault allocation arguments are central to the litigation.
Prescriptive Period
Louisiana’s term for statute of limitations. The legal deadline to file a lawsuit. For personal injury, it is two years from the date of injury under La. C.C. Art. 3493.1 (effective July 1, 2024).
The Prescriptive Period for personal injury in Louisiana is two years from the date of injury under La. C.C. Art. 3493.1, effective July 1, 2024. Product liability claims against manufacturers not domiciled in Louisiana may be filed in federal court under diversity jurisdiction.
Contingency Fee
A fee arrangement where the attorney is paid a percentage of the recovery and only if there is a recovery. The client pays nothing upfront and owes no attorney fees if the case is unsuccessful.
Morris & Dewett handles these cases on a Contingency Fee basis. There are no upfront fees. Attorney fees are paid from the recovery only if the case succeeds. Product liability cases against manufacturers require significant investment in engineering experts and discovery. Contingency representation means you can pursue those claims regardless of your financial situation. View our case results for examples of our recoveries in large truck and product liability cases.