12.5 Commercial Auto Endorsements

Key Takeaways

  • Drive Other Car (CA 99 10) gives a named individual with no personal auto policy personal-auto-like coverage on non-owned autos.
  • Hired auto physical damage and Symbol 9 non-owned liability fill recurring rented/employee-car gaps.
  • Lessor Additional Insured (CA 20 01) names a leasing company as additional insured and loss payee.
  • An experience mod below 1.00 credits premium; above 1.00 debits it (actual vs. expected losses).
  • BAPs are often auditable: inception premium is a deposit, trued-up at expiration as vehicles change.
Last updated: June 2026

Tailoring the Commercial Auto Policy

The Business Auto Coverage Form is intentionally broad but generic; endorsements add, restrict, or modify coverage for specific exposures. Knowing the common ISO 'CA' endorsements by name and effect is heavily tested.

EndorsementEffect
Drive Other Car (CA 99 10)Extends liability/med-pay/UM to named individuals while driving non-owned autos — used by executives with a company car but no personal auto policy
Hired Auto Physical DamageAdds comprehensive/collision on rented/borrowed autos (Symbol 8 exposure)
Individual Named Insured (CA 99 17)Broadens coverage so an individual owner and family get personal-auto-like protection on the BAP
Lessor – Additional Insured and Loss Payee (CA 20 01)Names the lessor of a leased auto as additional insured and loss payee
Mobile Equipment (CA 20 15)Schedules mobile equipment to be treated as covered autos
Fellow Employee Coverage (CA 20 55)Deletes the fellow-employee exclusion so employees can sue co-employees

Drive Other Car (DOC) in Detail

The BAP's 'who is an insured' rule does NOT cover a named individual while driving a NON-owned auto for personal use. An executive whose only vehicle is a company car therefore has a gap on weekends and rentals. Drive Other Car (CA 99 10) fills it by extending liability, medical payments, UM/UIM, and (optionally) physical damage to the named person and resident spouse while using autos the company does not own.

Trap: DOC is for individuals who have NO personal auto policy of their own — it mimics personal coverage. It is not a fleet-wide extension.

Hired and Non-Owned Liability

Two distinct gaps recur on the exam:

  • Hired auto liability — needed when the business rents/leases vehicles; Symbol 1 already includes it, but Symbol 2 risks must add it.
  • Employees as insureds for non-owned use — by endorsement, the named insured's vicarious liability when employees use their OWN cars on business is covered (Symbol 9), but the employee personally is not made an insured.

Rating Modifiers and the Experience-Mod Concept

Commercial auto premiums for larger fleets can be adjusted by an experience modification (experience mod / EMR) that compares the insured's actual losses to expected losses for similar risks.

Worked experience-mod example

If the expected losses for a fleet are $100,000 and the actual losses are $70,000, a simplified mod = actual / expected = 70,000 / 100,000 = 0.70. Applied to a $50,000 manual premium: $50,000 x 0.70 = $35,000 — a 30% credit for better-than-average loss experience. A mod above 1.00 (e.g., 1.25) is a debit, raising premium for worse-than-average losses.

Other rating levers

LeverEffect on premium
Higher deductible (physical damage)Lowers premium
Fleet rating (9+ power units)Blends fleet loss experience
Radius of operation / use classLong-haul and commercial use cost more
Driver MVR / loss historySurcharges for violations and at-fault claims

Audit note: Because vehicles are added and deleted mid-term, the inception premium is a deposit premium and many BAPs are auditable, with the final premium trued-up at expiration.

More Endorsements You Must Recognize

Exam writers test the name-to-effect link for several additional ISO commercial-auto endorsements:

EndorsementEffect
Rental Reimbursement (CA 99 23)Pays a daily/maximum amount for a substitute vehicle after a covered physical-damage loss
Auto Loan/Lease Gap (CA 04 79)Pays the difference between the auto's ACV and the loan/lease balance after a total loss
Pollution Liability – Broadened (CA 99 48)Restores limited coverage for pollutants being transported by a covered auto
Waiver of Transfer of Rights (CA 04 44)Waives subrogation against a party named by contract
Expanded Transportation ExpenseIncreases the standard $20/day, $600-max transportation-expense allowance after theft of a private passenger auto

Gap-coverage trap: Auto physical damage pays only ACV. If a financed truck is totaled while the loan balance exceeds ACV, the borrower still owes the lender the shortfall — only Loan/Lease Gap (CA 04 79) closes that hole.

Choosing Endorsements From a Fact Pattern

The practical skill the exam rewards is reading a business description and naming the gap-filling endorsement.

  • A startup leases all its delivery vans -> Lessor Additional Insured (CA 20 01) plus hired-auto physical damage.
  • The owner drives only the company SUV and has no personal policy -> Drive Other Car (CA 99 10).
  • A contractor finances trucks with little money down -> Loan/Lease Gap (CA 04 79).
  • Employees use personal cars for deliveries -> ensure Symbol 9 non-owned liability is on the declarations.
  • A client contract requires the insured to waive subrogation -> Waiver of Transfer of Rights (CA 04 44).

Final synthesis: the Business Auto policy is a kit. Symbols decide WHICH autos; the coverage sections decide WHAT perils; endorsements close the remaining gaps; and rating modifiers, deductibles, and audits decide the PRICE. Hold those four layers separate and most commercial-auto questions resolve cleanly.

Test Your Knowledge

A company president drives a company-owned car as her only vehicle and has no personal auto policy. Which endorsement gives her personal-auto-like protection when she drives a rented car on vacation?

A
B
C
D
Test Your Knowledge

A fleet has expected losses of $200,000 and actual losses of $240,000, producing an experience mod of 1.20. Applied to a $60,000 manual premium, what is the modified premium?

A
B
C
D