The US DOT Number serves as a unique identifier when collecting and monitoring a company's safety information acquired during audits, compliance reviews, crash investigations, and inspections.

In general, companies are required to have interstate Operating Authority (MC number) & US DOT number when:

o Transport passengers in interstate commerce (for a fee or other compensation, whether direct or indirect)
o Transport federally-regulated commodities owned by others or arranging for their transport, (for a fee or other compensation, in interstate commerce)