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USDOT 3973586 · FONTANA, CA
Contact details are partially masked to protect privacy. Verified information appears on the official FMCSA Certificate of Authority.
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Request Certificate →USDOT 3973586 identifies 4J DIAZ TRANSPORT LLC of FONTANA, CAwithin the Federal Motor Carrier Safety Administration (FMCSA) registry. Every interstate motor carrier operating commercially in the United States is assigned a unique USDOT number that links to its safety record, operating authority, insurance filings, and inspection history. Use this number to look up the carrier on SAFER, verify a broker or shipper’s record, or pull the official Certificate of Authority document.
FMCSA operating authority with status “Active” indicates the current eligibility of the carrier to haul regulated freight or passengers across state lines. Brokers, shippers, and insurers typically check this field before onboarding a new carrier. The Certificate of Authority is the signed FMCSA document that confirms this status in writing — it’s what you receive as a PDF through CertExpress.