Under 49 CFR Part 391, motor carriers must maintain a Driver Qualification (DQ) file for every CDL driver. Required documents include: driver application (391.21), inquiry to previous employers (391.23), annual Motor Vehicle Record (MVR) check (391.25), road test certificate or equivalent (391.31/33), annual review of driving record (391.25), and a copy of the current Medical Examiner's Certificate (391.43). The DQ file is separate from the drug and alcohol testing records, though both must be maintained. Files must be retained for 3 years after the driver leaves. Incomplete DQ files are a common FMCSA audit finding that contributes to CSA Unsafe Driving and Driver Fitness BASIC scores.