When a commercial truck is involved in an accident, the collision happens in seconds. The accountability fight may last months or years. One regulation often decides whether the injured person can identify the right defendants quickly enough to preserve evidence and build a clean liability story. 49 CFR 390.21T requires a self propelled commercial motor vehicle to display two core identifiers. The vehicle must show the legal name or a single trade name of the motor carrier, and it must show the motor carrier’s USDOT number with the letters “USDOT” immediately before the number. The marking must appear on both sides of the vehicle. The letters must contrast sharply with the background. The marking must remain legible from 50 feet away while the vehicle stands still. The motor carrier must keep the marking in a condition that meets those requirements.
That is not cosmetic. It is a compliance obligation that demands daily execution. A carrier needs drivers, yard staff, and maintenance staff who understand what “legible from 50 feet” means in the real world. A carrier needs inspections that catch peeling vinyl, road grime, crash damage, poorly placed decals, and box trucks that collect soot until the company name disappears. A carrier also needs procedures for leased equipment and owner operators so the truck displays the correct operating identity when the load moves.
From a personal injury perspective, the marking rule influences four high stakes issues.
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