Definition of trucker: California Insurance Code §11580.9(h) defines a trucker as any person or organization engaged in the business of transporting property by auto for hire. The key words are property and for hire, so a firm hauling only its own goods is a private carrier, not a trucker. Under that subdivision, when a trucker is operating the power unit, the trucker's policy is primary for the power unit and its trailers.

The Motor Carrier Act of 1980 (Public Law 96-296) loosened Interstate Commerce Commission control over who could enter trucking and over rates, which is why it is called deregulation. Its safety side lives on in federal minimum financial responsibility. 49 U.S.C. §31139 sets at least $750,000, and 49 CFR §387.9 applies that amount to for-hire interstate carriage of nonhazardous property in vehicles of 10,001 pounds or more.

Why a separate auto program: trucking often uses vehicles and drivers the carrier does not own and relies on leases and hauling agreements. ISO's Motor Carrier Coverage Form (CA 00 20) is built around this. In set cases it makes lessors and trailer owners insureds, and which policy is primary can turn on the written lease between two carriers. Its definition of motor carrier reaches both for-hire and private carriers. Vehicle size alone does not bar the BAP.