The “UCR Handbook” (effective February 29, 2024) provides detailed guidance on the Unified Carrier Registration (UCR) program, which is a federal-state revenue program for interstate motor carriers, brokers, and leasing companies. It explains the UCR’s legal foundations, its board structure, and the obligations for businesses subject to its requirements, such as annual registration and fee payment. The handbook covers categories of businesses that must comply, the process for registration, and fee structures based on fleet size. It also discusses audits, enforcement mechanisms, and specific rules for certain types of operations like leasing companies and hazardous materials carriers. Key points include distinguishing UCR from similar programs, defining interstate commerce, and providing clarification on UCR’s restrictions on state authority.