What is CDLIS?
CDLIS — the Commercial Driver's License Information System — is the AAMVA-operated nationwide database that links every state CDL on a single driver, so motor carriers can pull a multi-state license history in one query instead of probing each state DMV individually.
CDLIS was created by the Commercial Motor Vehicle Safety Act of 1986 and is operated by the American Association of Motor Vehicle Administrators (AAMVA) under contract to FMCSA. Every state DMV is required to feed CDL events (issuance, conviction, withdrawal, disqualification) to the central CDLIS pointer record, which then routes back to the state of record for the underlying detail.
For driver screening, CDLIS solves the multi-state license problem. A driver can hold (or have held) CDLs in multiple states over their career; an MVR pull only returns the record for the state queried. CDLIS lists every state where the driver has held a CDL since 1996, so a carrier can hit each one and assemble a complete license history.
49 CFR §391.23(a) requires pre-employment investigation across every state where the driver held a license or permit during the prior three years. For drivers with multi-state CDL history that requirement is impossible to satisfy without CDLIS or an equivalent multi-state lookup.
A CDLIS history report typically returns 1) every state of CDL issuance, 2) the dates of issuance and any subsequent license actions (withdrawal, disqualification), and 3) the federal CDLIS-derived driver number used to cross-link the records. Combined with state MVRs from each listed state, it forms the §391.23 license-history dossier.