SCACs are commonly used by the automobile, petroleum, forest products, and chemical industries; as well as suppliers to retail businesses, carriers engaged in railroad piggyback trailers, and ocean container drayage.Freight Carriers who participate in the Uniform Intermodal Interchange Agreement (UIIA) are required to maintain a SCAC. Certain groups of SCACs are reserved for specific purposes. Codes ending with the letter "U" are reserved for the identification of freight containers. Codes ending with the letter "X" are reserved for the identification of privately owned railroad cars. Codes ending with the letter "Z" are reserved for the identification of truck chassis and trailers used in intermodal service.
SCAC is also used to identify an ocean carrier or self-filing party, such as a freight forwarder, for the Automated Manifest System used by US Customs and Border Protection for electronic import customs clearance and for manifest transmission as per the USA's "24 Hours Rule" which requires the carrier to transmit a cargo manifest to US Customs at least 24 hours prior to a vessel's departure at port of loading.