Primary Liability Insurance for Motor Carriers

What Primary Liability Insurance Covers

Primary liability insurance is the foundational coverage that every interstate motor carrier must carry. It protects third parties -- other drivers, pedestrians, and property owners -- against financial losses caused by the carrier's operations. This policy pays for bodily injury, death, and property damage resulting from accidents involving the carrier's vehicles.

Primary liability does not cover damage to the carrier's own vehicles or cargo. Those require separate physical damage and cargo insurance policies.

Federal Minimum Coverage Amounts

FMCSA sets minimum primary liability limits under 49 CFR 387.9:

• $750,000 for carriers hauling non-hazardous general freight in vehicles over 10,001 lbs GVWR
• $1,000,000 for carriers transporting hazardous materials requiring placarding
• $5,000,000 for carriers hauling certain oil, hazardous waste, or hazardous substances

These are combined single limits (CSL), meaning the dollar amount applies to the total of bodily injury and property damage per occurrence.

Why Most Carriers Carry More Than the Minimum

While federal law requires only $750,000 for general freight, the reality is that most carriers purchase $1,000,000 or more in primary liability coverage. Several forces drive this:

1. Shipper and broker requirements: Many load boards and contract shippers require $1,000,000 as a baseline
2. Rising verdict amounts: Jury awards in trucking accident cases have increased dramatically, with nuclear verdicts regularly exceeding $10,000,000
3. Protection against personal liability: Insufficient coverage can pierce the corporate veil, exposing owners personally
4. Lender requirements: Equipment financing companies often mandate coverage above the federal minimum

Policy Structure and Filing

A primary liability policy for motor carriers is filed with FMCSA using Form BMC-91 (for policies issued by a licensed insurer) or Form BMC-91X (for policies issued by a self-insured carrier or through a risk retention group). This filing creates a public record that shippers, brokers, and enforcement agencies can verify.

Key policy components include:

• Named insured: The motor carrier entity matching the USDOT and MC number
• MCS-90 endorsement: A mandatory endorsement that guarantees the insurer will pay claims even if the policy would otherwise not cover them, protecting the public interest
• Scheduled vehicles: Some policies cover specifically listed units; others provide blanket coverage for all vehicles operated under the carrier's authority

The MCS-90 Endorsement

The MCS-90 is unique to commercial trucking. It is not an insurance policy itself but an endorsement that attaches to the primary liability policy. It guarantees that if the carrier causes bodily injury or property damage, the insurer will pay up to the minimum financial responsibility amount -- even if the specific loss would otherwise be excluded by the policy terms.

After paying under the MCS-90, the insurer can seek reimbursement from the carrier for amounts it would not otherwise have owed. This makes the MCS-90 a form of public protection rather than traditional insurance.

Maintaining Compliance

A carrier's operating authority depends on maintaining continuous insurance coverage. If your insurer cancels or non-renews your policy, they must give FMCSA 30 days' notice by filing a cancellation. During that window, you must secure replacement coverage to avoid an authority suspension.

You can monitor your filing status through our authority lookup tools and check insurer filings on your carrier profile. Any gap in coverage, even a single day, can trigger enforcement action and loss of the ability to operate.