Underinsured Motorist Coverage in Phoenix: When the At-Fault Driver Doesn’t Have Enough
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Call For A Free Consultation(602) 345-1818
You were rear-ended on the 101. The driver who hit you had insurance, technically. The problem is their policy maxes out at $25,000 per person, and your ER visit, MRI, and orthopedic follow-ups already blew past that number in week one. So where does the rest of the money come from?
That’s what this article is for. If you’re searching for an underinsured motorist Phoenix lawyer, you already know the at-fault driver’s coverage isn’t enough. Below, we walk through how underinsured motorist (UIM) coverage works in Arizona, how to figure out what you have, why your own insurance company will likely fight you, and what the law lets you do about it. If you’d rather just talk it through, call us: (602) 345-1818. Free case review.
UIM is a part of your own auto policy. It pays for your injuries when the at-fault driver has some liability insurance, but not enough to cover what you’re owed. It is first-party coverage, meaning you collect from your own insurer, not the other driver’s.
Two separate buckets often get lumped together in conversation:
Both come out of the same Arizona statute (A.R.S. § 20-259.01), and both have to be offered to you by your insurer. They kick in at different moments, though, and confusing them costs people money.
UIM is triggered when three things are true:
Example: the at-fault driver carries Arizona’s minimum 25/50/15 policy. Your medical bills, lost wages, and pain and suffering total $90,000. Their carrier tenders the $25,000 per-person limit. You’re $65,000 short. That gap is what UIM is designed to fill, up to the UIM limits on your own policy.
If the other driver had no policy at all, that’s a UM claim instead. If you want a broader walkthrough of that scenario, here’s what to do when the other driver has no insurance.
For policies issued or renewed beginning July 1, 2020, Arizona’s minimum liability limits are 25/50/15: $25,000 bodily injury per person, $50,000 per accident, and $15,000 property damage. That’s the floor a “fully insured” driver in Arizona can legally carry.
Here’s what most people don’t realize: a single ER visit with imaging and a few specialist consults can easily exceed $25,000 before you’ve started physical therapy. Surgery puts you past it on day one. So when we say the at-fault driver was “insured,” that often just means “insured enough to drive legally,” not “insured enough to make you whole.”
UIM exists because those minimums often don’t cover real injuries. For most drivers, it’s the only practical way to protect themselves from a low-limit at-fault driver.
The two coverages look similar on a declarations page and often share a single premium line. They are not the same:
| UM (uninsured motorist) | UIM (underinsured motorist) | |
|---|---|---|
| Other driver’s insurance status | None, or hit-and-run | Has insurance, but limits too low |
| When it triggers | Immediately, no other policy to exhaust | After at-fault liability limits are exhausted |
| Typical claim sequence | File with your own carrier directly | Settle with at-fault carrier first, then pursue UIM gap |
Why this matters: a lot of UIM claims get fumbled because the claimant accepts the at-fault driver’s policy-limits offer without notifying their own UIM carrier first. Most UIM policies require the carrier’s consent before you release the at-fault driver, or the UIM claim can be jeopardized. Read your policy. Better, have a lawyer read it before you sign anything.
Arizona insurers must offer UM/UIM coverage to every applicant under A.R.S. § 20-259.01. You can decline it, but only in a signed written rejection. If you didn’t affirmatively reject UIM in writing when you bought the policy, it’s likely on there.
If you take UIM, the minimum limits track Arizona’s liability minimums: 25/50. You can buy higher. Most people who actually understand what UIM does buy higher, often matching their liability limits.
To check what you have:
Bring the declarations page to your consultation. Half the puzzle is knowing exactly what’s available.
This is where competitor pages tend to go silent. A.R.S. § 20-259.01 contains anti-stacking provisions that, in general terms, prohibit adding the UM/UIM limits of multiple vehicles or policies together to get a higher total. The exact subsection language has been amended over the years, so the specific clause should be verified against the current version of the statute, but the operating rule is the same: in Arizona, you generally don’t get to stack.
In a state that allowed stacking, a household with three insured cars at $50,000 UIM each could potentially access $150,000 in UIM. Arizona doesn’t allow that. You’re generally limited to the single highest applicable UIM limit, not the sum.
What this means in practice for a multi-vehicle household:
The anti-stacking rule has real bite. If a competitor’s website tells you to “stack your UM coverage,” that advice doesn’t apply in Arizona.
A typical UIM sequence looks like this:
Step 6 is where unrepresented claimants get hurt most often. Step 8 is where having counsel changes the carrier’s posture.
The hardest thing to wrap your head around: in a UIM claim, the adversary IS your own insurance company. The same carrier you’ve been paying premiums to for years now has a financial interest in valuing your claim as low as possible.
UIM adjusters use the same playbook as third-party adjusters:
None of that is personal. It’s the economics of a first-party insurance claim. Knowing that going in changes how you handle the relationship.
Arizona recognizes a tort for first-party insurance bad faith. The Arizona Supreme Court recognized the tort in Noble v. National American Life Insurance Co., 128 Ariz. 188, 624 P.2d 866 (1981), and refined the standard in Rawlings v. Apodaca, 151 Ariz. 149, 726 P.2d 565 (1986). Under that framework, an insurer that fails to handle a claim with reasonable care, including unreasonable denial or delay of a valid UIM demand, can be liable beyond the contract. That exposure can include the unpaid policy benefit, consequential damages, and in egregious cases punitive damages, subject to the facts and the standard of proof at trial.
What an unreasonable UIM carrier looks like in practice:
If your carrier is doing any of that, you may have a bad-faith claim layered on top of the UIM claim itself. A bad-faith case can change the carrier’s calculus, and a serious lowball settlement offer on a well-documented UIM claim is often the opening move that puts bad-faith exposure in play.
The contract value of the claim is capped at the UIM limits. Bad-faith damages are not capped the same way. That’s why carriers behave differently once bad faith is on the table.
You are generally not required to give a recorded statement to the other driver’s insurance company. Their adjuster doesn’t have a contract with you.
Your own insurer is different. Most auto policies contain a cooperation clause that requires the insured to assist the carrier in investigating a claim. That can include providing a recorded statement, submitting to an examination under oath, and producing documents. Whether you actually have to give a recorded statement, and on what terms, depends on the specific language of your policy, the type of claim, and the timing of the request.
Practical guidance:
Arizona is a pure comparative fault state. Under A.R.S. § 12-2505, your recovery is reduced by your percentage of fault, but is not eliminated even if you’re more than 50% at fault. That rule applies to UIM claims too, because a UIM claim stands in the shoes of the underlying bodily-injury claim against the at-fault driver.
Why this matters for strategy: UIM adjusters frequently inflate the claimant’s fault percentage to shrink the payout. A 30% fault assignment on a $90,000 claim cuts $27,000 off the top. The counter is documentary evidence: the police report, scene photos, vehicle damage patterns, dashcam or surveillance video, and witness statements collected early.
We treat fault evidence the same way in a UIM claim that we would in a third-party claim against the other driver. The adjuster is making the same argument, just with a different letterhead. For a deeper look at how this plays out, here’s our breakdown of Arizona’s comparative negligence rule.
What’s recoverable through UIM, assuming fault is established:
Both categories are available because UIM is meant to put you in the position you would have been in if the at-fault driver had carried adequate limits. Claim value depends on injury severity, treatment history, fault proof, available insurance, and how well damages are documented; we do not publish dollar ranges as typical outcomes.
One related note for readers thinking about coverage beyond a typical passenger-car crash: commercial trucks operating in interstate commerce at 10,001 pounds or more are required by federal regulation (49 C.F.R. § 387.9) to carry a minimum of $750,000 in liability coverage, and often far more for hazardous cargo. UIM exhaustion looks different in a commercial-truck case because the underlying liability tower is usually much taller than a 25/50 personal policy.
This is a trap. The underlying bodily-injury claim against the at-fault driver carries the two-year statute of limitations under A.R.S. § 12-542. A UIM claim is contractual against your own insurer, so a different limitation period can apply under the policy itself.
Why it matters: people sometimes assume the UIM claim is “safe” because it’s against their own carrier, and they let the two-year clock against the at-fault driver run. If the at-fault driver becomes immune to suit because the statute has expired, the UIM carrier may take the position that you can no longer establish liability against an uninsured or underinsured motorist, weakening or extinguishing the UIM claim.
Practical rule: preserve both the BI claim and the UIM claim until each is either resolved or properly tolled. Don’t rely on UIM to be the clean-up crew after the BI clock has run.
No. Arizona requires insurers to offer UM/UIM coverage to you, but you can reject it in writing. If you didn’t sign a written rejection, the coverage is presumed to be on the policy.
Yes, that’s exactly when UIM applies. But you need to notify your own UIM carrier before accepting the at-fault tender and signing a release. Most UIM policies require the carrier’s written consent or a chance to substitute the limits to protect their subrogation rights. Failing to do this can void the UIM claim.
Rating practices vary by carrier and are governed by the carrier’s filed rate plan with the Arizona Department of Insurance and Financial Institutions. Whether a not-at-fault UIM claim affects your premium at renewal depends on your specific carrier’s rules. Ask your agent for the carrier’s policy in writing and review your renewal notice carefully.
You generally can’t stack the limits to add them together. You may, however, be entitled to access the single highest applicable UIM limit among the policies that cover you. Which policy applies, and at what limit, depends on whose vehicle you were in, who owned the policy, and the policy language.
A clean UIM claim can resolve in a few months after treatment is documented. A contested UIM claim involving disputed fault, disputed damages, or carrier delay can take a year or longer, and arbitration or litigation adds time. Serious-injury UIM claims tend to take longer because the dollars are higher and the documentation burden is heavier.
You don’t need one to open a claim. Whether you need one to resolve a claim depends on the size of the gap, the carrier’s posture, and how clean the liability picture is. If your damages are well above the at-fault driver’s limits and your own carrier is dragging its feet or undervaluing the file, that’s the moment counsel changes the outcome.
If the at-fault driver’s insurance isn’t enough to cover what you’ve lost, your own UIM coverage is the next move, and how you handle the first 30 days matters more than people realize. We handle UIM claims through our Phoenix car accident practice, including the bad-faith variety where the carrier won’t pay a fair number on a documented file.
Free case review with Jared J. Pehrson: (602) 345-1818. No attorney’s fees unless we recover; case costs and fee terms are set out in the written fee agreement. We answer 24/7.
By Jared J. Pehrson | Impact Legal Car Accident Attorneys
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