This type of insurance is typically designed to cover the liability of a freight broker from an auto liability claim on a contingent basis. The motor carrier’s insurance is in place as the primary coverage and contingent auto liability is present to pick up a valid claim within the scope of the policy that a motor carrier’s policy does not cover or if the motor carrier’s insurer becomes insolvent (within the terms of the policy)
There may be other conditions that must also be present or satisfied for the coverage to kick-in. The policies can be written on both an aggregate or a per occurrence basis. Defense may or may not be covered depending on how the form is written and whether defense is inside of or outside of the policy limits. There also may be no defense coverage if the trucking company is providing defense. It is best to understand your policy and ask questions before you bind coverage. Punitive and exemplary damages are typically excluded.
Coverage can often be written to limits of $15 million-$25 million before needing to get additional limits from an excess market.