Commercial Auto Coi Requirements: A Practical Guide for Agencies

Commercial auto COI requirements trip up more brokers than any other certificate issue. The rules are specific, the federal overlay is real, and a single wrong coverage symbol can create an uninsured gap. This guide covers the 8 things you need to know to get it right.

Key Takeaways

• The ACORD 25 Automobile Liability section uses covered autos symbols that determine which vehicles are actually covered. Symbol 1 (any auto) is the only symbol that meets "any auto" contract language.
• Federal FMCSA minimums are law, not contract preference: $750K for general freight, $5M for hazmat Class A/B carriers, per FMCSA 2024 regulations.
• ISO CA 20 48 is the standard additional insured endorsement for commercial auto. Many carriers use proprietary forms that must be verified separately.
• Hired and non-owned auto (HNOA) does not appear automatically on a commercial auto policy. It requires a specific endorsement, typically ISO CA 20 54 and CA 20 01 or a combined form.
• The MCS-90 endorsement is a federal financial responsibility guarantee, not a standard liability extension. It attaches to the auto policy but operates independently from the policy's coverage terms.
• According to ACORD 2025, incomplete Description of Operations on commercial auto certificates is among the top 5 causes of certificate-related E&O claims at agencies.

Why Commercial Auto COI Requirements Demand Specific Attention

Most brokers handle GL certificates on autopilot. Commercial auto certificates require a different level of scrutiny. Federal law intersects with contract requirements, policy structure directly affects coverage, and the ACORD 25 form has fields specific to commercial auto that carry legal significance.

IIABA 2025 data shows that commercial auto accounts generate 2.3x more certificate correction requests than general liability accounts. The reason is straightforward: commercial auto has more moving parts.

1. Commercial Auto Has Its Own Section on the ACORD 25

The ACORD 25 certificate of insurance places commercial auto liability in a dedicated section labeled "Automobile Liability." This section is separate from the General Liability, Umbrella, and Workers' Comp sections, and it requires specific data that does not appear elsewhere on the form.

Within the Automobile Liability section, the broker must indicate the limit structure: either a combined single limit (CSL) or split limits (bodily injury per person, bodily injury per occurrence, and property damage). The section also captures the covered autos symbol, which is one of the most consequential fields on the entire certificate.

Understanding what belongs in each field of the Automobile Liability section prevents the most common commercial auto certificate errors before they reach the certificate holder.

2. The Covered Autos Symbol Is Not a Formality

The covered autos symbol tells the certificate holder exactly which vehicles the policy covers. It is a numbered designation defined by ISO and used consistently across commercial auto policies. The most commonly referenced symbols are:

A contract requiring coverage for "any auto" requires symbol 1. If the policy only covers owned autos (symbol 2), the contract requirement is not met, even if the policy limit is correct. Certificate holders who review certificates carefully will catch this mismatch and reject the certificate.

According to ISO 2024 commercial auto filing data, symbol 2 policies are the most commonly issued but the most frequently mismatched against contract language that specifies "any auto."

3. Contract Minimums Almost Always Exceed State Minimums

State minimums exist to protect the public on public roads. Commercial contract minimums exist to protect businesses from catastrophic loss. These two sets of requirements rarely align, and commercial contract minimums are almost always the controlling standard for your clients.

The most commonly required minimum limits by contract type:

Most state commercial auto minimums fall between $30,000 and $750,000. California requires $750,000 CSL for commercial vehicles over 10,000 GVW. Texas requires $500,000 CSL for certain commercial vehicles. Neither of those figures meets the $1M CSL required by a typical general commercial contract.

When a client presents a contract with an auto liability requirement, verify against the contract minimum, not the state minimum. The state minimum is the legal floor; the contract minimum is the actual requirement your client must meet.

4. FMCSA Filing Requirements Are Federal Law

For-hire motor carriers operating in interstate commerce face a separate layer of requirements beyond state law and private contracts. The Federal Motor Carrier Safety Administration (FMCSA) mandates minimum liability coverage filed directly with the agency. These filings are mandatory, tracked federally, and failure to maintain them can result in revocation of operating authority.

FMCSA 2024 minimum liability requirements by cargo type:

Proof of FMCSA filing is not the same as a standard COI. The filing is made by the carrier's insurer directly to FMCSA using Form BMC-91 or BMC-91X. A certificate of insurance does not substitute for this filing. When a client needs to prove compliance to a shipper or broker that requires FMCSA authority verification, they need both the COI and a copy of the active FMCSA filing.

5. Adding Additional Insured to Commercial Auto Is Less Standardized Than GL

On general liability policies, ISO CG 20 10 and CG 20 37 are the near-universal standard for additional insured endorsements. Commercial auto additional insured endorsements are less uniform. ISO CA 20 48 is the standard form, but carrier adoption varies significantly.

ISO CA 20 48 adds the named certificate holder as an additional insured for liability arising from the use of covered autos. However, many carriers use proprietary endorsements that may restrict the additional insured's coverage compared to the ISO standard. Some proprietary forms limit coverage to the insured's negligence only, excluding the additional insured's own partial negligence.

When a contract requires additional insured status on commercial auto, verify:

1. The carrier has issued an AI endorsement, not just noted "additional insured" in the Description of Operations without a form number.
2. The form used (ISO CA 20 48 or carrier equivalent) actually provides the coverage the contract requires.
3. The certificate reflects the AI endorsement with the correct form number in the Description of Operations.

According to ACORD 2025, certificates that reference additional insured status without a corresponding endorsement on the policy are one of the most frequent sources of coverage disputes in commercial auto claims.

6. Hired and Non-Owned Auto Is Not Automatic

Hired and non-owned auto (HNOA) coverage protects the business when an employee uses a personal vehicle or a rented vehicle for business purposes and causes an accident. This coverage does not appear automatically on a standard commercial auto policy. It requires an endorsement.

The two ISO endorsements that provide HNOA coverage are:

• ISO CA 20 54: Hired Autos coverage
• ISO CA 20 01: Non-Owned Autos coverage

Many carriers offer a combined HNOA endorsement that incorporates both. Contracts commonly require HNOA, and the certificate must reflect the endorsement. The Automobile Liability section of the ACORD 25 has a checkbox for "Hired Autos Only" that is used when the insured has no owned autos but carries HNOA. When HNOA is an endorsement to a policy that also covers owned autos, it should be noted in the Description of Operations with the specific endorsement form number.

A business that owns no vehicles but has employees who drive personal vehicles for work still needs HNOA coverage. Standard GL excludes auto liability. Without HNOA, a delivery driver in their own car making a business errand creates an uninsured exposure for the employer.

7. The MCS-90 Endorsement Is a Federal Financial Responsibility Guarantee

The MCS-90 endorsement is required by FMCSA for motor carriers operating with federal authority. It is not a standard auto liability extension. The MCS-90 is a federal financial responsibility endorsement that guarantees minimum liability coverage to members of the public injured by the carrier's vehicles, regardless of policy exclusions.

This distinction matters for certificate management. The MCS-90 is attached to the commercial auto policy, but it can respond to claims even when the underlying policy would otherwise deny coverage, such as when a driver was operating outside the scope of their permitted use. The MCS-90 essentially makes the insurer a guarantor of last resort for public injury claims against federal motor carriers.

For brokers managing motor carrier accounts:

• Verify the MCS-90 is attached to the current policy term, not the prior policy.
• Confirm the FMCSA filing is active by checking FMCSA's SAFER system or the carrier's filing confirmation.
• Note "MCS-90 endorsement attached" in the Description of Operations on certificates issued for transportation contracts that require proof of FMCSA authority.

8. The Description of Operations Is Where Commercial Auto Details Are Confirmed

The Description of Operations box on the ACORD 25 is where brokers document coverage details that do not fit in the standard checkbox fields. For commercial auto, this is where certificate holders look to confirm that the policy meets contract requirements beyond the basic limit.

A well-structured Description of Operations for a commercial auto certificate should include:

• The covered autos symbol, stated explicitly: "Commercial auto policy written on symbol 1 (any auto) basis."
• HNOA endorsement confirmation: "Coverage includes hired and non-owned auto liability per ISO CA 20 54 / CA 20 01."
• Additional insured notation: "Certificate holder is named as additional insured per ISO CA 20 48."
• MCS-90 notation if applicable: "MCS-90 endorsement attached. FMCSA Form BMC-91X on file."

Vague notations like "as required by contract" or "additional insured as agreed" do not provide certificate holders with the specific information they need to verify compliance. According to IIABA 2025, certificate holders in transportation and construction are increasingly returning certificates with vague DOO language and requesting specific endorsement references before accepting the certificate.

Coverage Type Reference Table

Frequently Asked Questions

What is the standard minimum commercial auto liability limit for most commercial contracts?

Most commercial contracts require $1,000,000 combined single limit (CSL) in auto liability. Transportation and logistics contracts commonly require $2,000,000 CSL. Government contracts range from $1,000,000 to $5,000,000 depending on the agency. Federal FMCSA requirements set a separate floor of $750,000 for general freight carriers and $5,000,000 for hazmat Class A/B carriers.

What does the covered autos symbol on an ACORD 25 mean?

The covered autos symbol is a numbered designation that identifies which vehicles the commercial auto policy covers. Symbol 1 covers any auto, including owned, hired, and non-owned. Symbol 2 covers only autos owned by the named insured. Symbol 8 covers hired autos only. Symbol 9 covers non-owned autos only. When a contract requires "any auto" coverage, only symbol 1 satisfies the requirement.

What is hired and non-owned auto coverage and when is it required?

Hired auto coverage protects the business when it rents, leases, or borrows a vehicle. Non-owned auto coverage protects the business when an employee uses a personal vehicle for business purposes. HNOA is required by contracts with vendors, government agencies, commercial landlords, and professional services firms whose employees drive to client sites. It does not appear automatically on a commercial auto policy and requires a specific endorsement.

What is the MCS-90 endorsement and who needs it?

The MCS-90 is a federal financial responsibility endorsement required by FMCSA for for-hire motor carriers with interstate operating authority. It guarantees minimum liability coverage to members of the public, regardless of whether the underlying policy would otherwise cover the claim. Motor carriers with FMCSA authority are required to have an active MCS-90 attached to their commercial auto policy. Brokers should verify this separately from the standard COI using FMCSA's SAFER system.

How do you add additional insured to a commercial auto policy?

Additional insured status on a commercial auto policy requires a formal endorsement, not just a notation on the certificate. ISO CA 20 48 is the standard endorsement for commercial auto additional insureds. Many carriers use proprietary forms. The endorsement must be issued by the carrier and documented on the certificate with the specific form number in the Description of Operations. A certificate that states "additional insured" without a corresponding endorsement does not actually confer additional insured status.

What commercial auto information should appear in the ACORD 25 Description of Operations?

The Description of Operations should specify: the covered autos symbol used on the policy, any HNOA endorsement form numbers (ISO CA 20 54 / CA 20 01 or carrier equivalent), the additional insured endorsement form number if applicable (ISO CA 20 48 or carrier equivalent), and MCS-90 notation if the insured is an FMCSA-registered motor carrier. Vague language does not satisfy contract requirements at most large certificate holders.

BrokerageAudit's COI Manager tracks commercial auto coverage symbols, HNOA endorsements, and MCS-90 filings for every account, flagging gaps before certificates are issued. See how it works →

Written by Javier Sanz, Founder of BrokerageAudit. Last updated April 2026.