Roughly one in ten Arizona drivers has no liability insurance. When one of them hits you, there's no policy to file against. That's what uninsured motorist (UM) coverage is for — and understanding how it works before you need it is worth your time.
What Arizona law requires
A.R.S. § 20-259.01 requires every auto insurer in Arizona to offer UM and underinsured motorist (UIM) coverage to policyholders in writing. The law doesn't require you to buy it — but if you never signed a written rejection, Arizona courts have found that UM coverage may apply by operation of law even if you don't recall opting in. That's a consumer protection provision many people don't know about until after a crash.
UM vs. UIM: the difference
UM coverage applies when the at-fault driver has no liability insurance at all. Your insurer steps into their shoes and compensates you up to your own UM limits. UIM coverage applies when the at-fault driver has insurance, but their limits aren't enough to cover your damages — UIM bridges the gap between what their policy pays and what you're actually owed.
Both coverages typically follow you in your own vehicle, a friend's car, and in many cases as a pedestrian or cyclist. If you were hurt in a hit-and-run and the driver was never identified, UM coverage often applies — the phantom vehicle is treated as uninsured under Arizona law.
What these coverages pay for
UM and UIM can cover medical expenses (emergency care, hospitalization, surgery, ongoing treatment), lost wages and lost earning capacity, pain and suffering, permanent disability or disfigurement, and wrongful death damages for surviving family members. What they don't cover is damage to your vehicle — that's what collision coverage is for.
Filing a UM/UIM claim: what to know
Claiming against your own insurer feels counterintuitive, but they still have a financial incentive to minimize what they pay you. Report the accident promptly — most policies require timely notice. Don't give a recorded statement without speaking to an attorney first. Document everything: photos, police reports, medical records, pay stubs.
If you're pursuing a UIM claim, Arizona law generally requires you to get your own insurer's consent before settling with the at-fault driver's liability carrier. Settling without that consent can cut off your UIM rights entirely.
Arizona's general personal injury statute of limitations is two years (A.R.S. § 12-542), but your policy may have shorter contractual deadlines for UM/UIM claims. Read our post on the Arizona statute of limitations for personal injury for the broader picture.
Insurance bad faith
If your own insurer unreasonably denies, delays, or undervalues your UM/UIM claim, Arizona recognizes a bad faith claim against them under A.R.S. § 20-461 and established case law — potentially including punitive damages in serious cases. This is a meaningful protection that gives injured people real leverage when carriers act unreasonably.
If you've been hurt by an uninsured or underinsured driver, or your insurer is pushing back on a valid claim, our car accident attorneys handle these cases throughout Phoenix and Scottsdale. Consultations are free, and there's no fee unless we win. Call (480) 418-SHER (7437) or reach out online.