Article source: Suzuki Law Personal Injury Law – AZ
An Arizona driver can look at an auto insurance declarations page, see a $100,000 underinsured motorist limit, and reasonably assume that $100,000 is the most the policy could provide after a serious crash.
With a policy covering multiple vehicles, that assumption can be wrong.
Arizona has an unusual statutory framework for uninsured and underinsured motorist coverage. In Franklin v. CSAA General Insurance Co., the Arizona Supreme Court held that a single policy insuring several vehicles provides separate UIM coverages for those vehicles. An insurer can restrict an insured to one coverage, but it must do so through the procedure Arizona law prescribes.
For someone injured in Phoenix, that means the number displayed next to “UIM” on the declarations page may not answer the entire coverage question. A claimant consulting a Suzuki Law personal injury lawyer after a severe collision may also need to determine how many vehicles were insured, what the policy says about selecting coverage, and whether the carrier complied with Arizona’s anti-stacking statute.
One policy can contain multiple UIM coverages
Underinsured motorist coverage becomes relevant when the insurance available from the driver who caused the collision is insufficient to compensate for the resulting bodily injury or death.
The key Arizona provision is A.R.S. § 20-259.01. Subsection H addresses situations in which multiple UM or UIM policies or coverages purchased by one insured on different vehicles apply to the same accident.
The significance of that language became the central issue in Franklin.
The policy involved two vehicles and provided UIM coverage of $50,000 per person. After the insured was killed in a collision, the insurer paid one $50,000 UIM limit. The claimant argued that because two vehicles were insured, a second $50,000 coverage was potentially available.
The Arizona Supreme Court agreed with the underlying coverage principle. In its 2023 Franklin opinion, the Court held that a multi-vehicle policy necessarily provides separate UIM coverages for the insured vehicles.
That does not mean those limits can always be added together.
Arizona allows anti-stacking but specifies how it must be done
“Stacking” means combining multiple applicable insurance coverages to increase the total amount potentially available for one loss.
Arizona law permits insurers to prevent stacking. Section 20-259.01(H) says that when multiple policies or coverages purchased by one insured on different vehicles apply, the insurer may limit coverage to one policy or coverage selected by the insured.
The important part of Franklin is that an insurer cannot accomplish that result however it chooses.
The Supreme Court held that subsection H supplies the statutory method for limiting stacking. Policy drafting that simply characterizes several insured vehicles as having one collective UIM coverage does not override the statute.
In Franklin, the insurer’s policy included language stating that its limit applied regardless of the number of covered cars or premiums paid. The Court nevertheless concluded that the statute treats UIM coverage associated with each vehicle as a separate coverage and that an insurer seeking to prohibit stacking must comply with subsection H.
That makes the anti-stacking language and notice history important pieces of the coverage analysis.
The 30-day notice provision can become critical
Arizona law gives insurers two routes for informing an insured that only one applicable coverage may be selected.
The policy itself can contain the required statement informing the insured of the right to select one policy or coverage. If it does not, subsection H requires the insurer, within 30 days after receiving notice of the accident, to notify the insured in writing of that right.
The timing is unusually specific.
It means a post-accident coverage review may involve more than obtaining the declarations page. The policy language, correspondence sent after the claim was reported, and the date the insurer received notice of the collision can all become relevant.
A carrier’s payment of one stated UIM limit also does not necessarily establish that no other coverage exists. Whether additional limits can be stacked depends on the policies or coverages involved and whether the statutory requirements for limiting them were satisfied.
The consequences of Franklin continued into 2025
The decision was not merely an academic interpretation of insurance language.
Several cases in the federal District of Arizona challenged insurers’ treatment of multi-vehicle UM and UIM coverage. One of them, Doyle v. Pekin Insurance Co., involved an Arizona policy covering more than one vehicle and allegations that the insurer had not permitted the available coverages to be stacked.
In September 2025, the federal court in Phoenix granted final approval of the class settlement. The approved settlement fund was $12.45 million. The certified class broadly included qualifying Arizona insureds whose policies provided UM or UIM coverage for more than one vehicle and whose claims had been paid at the limit associated with one vehicle.
A settlement does not establish liability in every other insurance dispute. What Doyle demonstrates is that the interpretation adopted in Franklin has practical consequences well beyond a single policyholder’s claim.
More insurance does not mean greater damages
Stacking also needs to be separated from the value of the underlying personal injury claim.
If an injured person has $150,000 in legally recoverable damages, discovering $300,000 in potentially applicable UIM limits does not transform the claim into a $300,000 loss. Insurance coverage determines the pool potentially available to satisfy damages; it does not manufacture additional damages.
The reverse situation is where the issue becomes especially important.
A person with catastrophic injuries might have damages far exceeding both the at-fault driver’s liability insurance and one UIM limit. If several vehicles were insured under the claimant’s policy, determining whether additional UIM coverage exists can materially change the amount of insurance available to respond to that loss.
That coverage inquiry is distinct from questions of negligence, comparative fault, and the calculation of personal injury compensation.
A declarations page is the starting point
Arizona’s multi-vehicle rule illustrates why insurance coverage cannot always be reduced to the largest number printed on the front of a policy.
After an underinsured crash, the relevant questions can include how many vehicles were covered, whether separate UM or UIM coverages were purchased, what anti-stacking language appears in the policy, and whether the insurer supplied the notice required by § 20-259.01(H).
Franklin established that Arizona treats the coverages associated with vehicles in a multi-vehicle policy separately for purposes of the stacking statute. The continuing litigation that followed shows why that distinction matters.
In a serious injury case, finding the applicable coverage can therefore be almost as important as calculating the loss itself.
This article provides general information about Arizona insurance and personal-injury law and is not legal advice for an individual case.
