A common carrier is a transportation company that offers services to the general public under regulated rates and terms — accepting freight from any shipper without discrimination. UPS, FedEx, and national LTL carriers (XPO, Old Dominion, Estes, Saia) are common carriers. By contrast, a contract carrier provides services exclusively to specific customers under privately negotiated contracts and is not obligated to accept freight from the general public.
Common Carrier Obligations
Common carriers accept legal obligations that private and contract carriers do not. They must: serve all customers without unreasonable discrimination, publish their rates and service terms (or make them available upon request), exercise reasonable care for freight in their possession, and maintain carrier liability insurance. The Carmack Amendment establishes the federal framework for common carrier liability for interstate freight in the U.S.
Common Carrier vs. Contract Carrier
Most major parcel and LTL carriers are technically common carriers but operate under a hybrid model — publishing tariff rates available to any shipper while simultaneously offering negotiated contract rates to high-volume customers. The practical distinction matters primarily for regulatory purposes and for shippers who do not qualify for contract rates and must pay published tariffs.