Mechanical Failures That Cause Crashes
Mechanical defects are involved in a significant share of large truck crashes, and most are preventable. The failures documented here share a common thread: they were identified during inspections, noted in maintenance records, or flagged by drivers, and ignored.
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29%FMCSA LTCCS
of truck crashes studied involved brake problems as a factor.
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19%CVSA ROADCHECK 2023
of roadside-inspected trucks were placed out of service.
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20%CVSA ROADCHECK 2023
of out-of-service violations were tire defects.
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56×FMCSA LTCCS
higher crash risk when cargo shifts in transit.
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Mechanical Defects by the Numbers
| Failure Point | Share of OOS Violations (Roadcheck 2023) | Crash Association (LTCCS) |
|---|---|---|
| Brake systems | 25% | Factor in 29% of crashes studied |
| Tires | 20% | Factor in 6% of crashes studied |
| Cargo securement | 12% | Factor in 4% of crashes; highest relative risk |
| Lights | 11% | Not separately measured |
Sources: CVSA International Roadcheck 2023; FMCSA Large Truck Crash Causation Study.
Frequently Asked Questions
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Yes. Federal regulations (49 CFR 396.11) require drivers to complete a Driver Vehicle Inspection Report (DVIR) noting any defects. Defects affecting safe operation must be repaired and certified before the vehicle returns to service. Carriers who ignore signed DVIRs face significant liability.
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Immediately. Carriers routinely dispatch rapid response teams to crash scenes. The truck should be inspected and photographed before any repairs are made. A litigation hold letter should be sent within 24 to 48 hours to preserve ECM data, maintenance records, and inspection reports.
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Liability typically extends to the carrier, whose duty to maintain its vehicles is widely treated by courts as non-delegable. If the defect was present during pre-trip inspections and not reported or addressed, the driver may also bear responsibility. In some cases, the manufacturer or repair shop may be named.
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Brake defects. Brake system violations accounted for a quarter of all out-of-service violations in Roadcheck 2023, and the federal Large Truck Crash Causation Study associated brake problems with 29% of the truck crashes it examined. Common defects include worn linings, leaking air lines, out-of-adjustment slack adjusters, and fully inoperable systems.
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Driver Error
Fatigue, impairment, and risky on-road behavior, plus the systemic pressures behind them.
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Crash Evidence
The critical window for preserving physical and electronic evidence before it disappears.
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Company Liability
How carrier hiring practices, training failures, and cost-cutting create conditions for preventable crashes.
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Federal Regulations
The FMCSA rules that govern trucking safety, and what happens when they fail or go unenforced.
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