FMCSA §396.17 requires that every motor vehicle be inspected at least once every 12 months. The AVIR (Annual Vehicle Inspection Report) is the form that documents that inspection.
Who does the inspection
A qualified inspector — either an in-house mechanic, a dealer, or a state inspection station — performs the inspection against the criteria in §393.
What the AVIR captures
Date of inspection, vehicle identification, name and qualifications of the inspector, and a checklist confirming the vehicle meets the §393 standards (brakes, frame, suspension, steering, fuel system, exhaust, lighting, etc).
Retention
Keep the AVIR for at least 14 months from the inspection date. A copy must be in the vehicle (or the AVIR sticker affixed) so a DOT officer can see it at roadside.