When Another Driver Has No Insurance
You're insuring two or more vehicles in Arizona and a carrier just asked whether you want uninsured motorist coverage on each one. The state doesn't require it, so you're trying to understand what happens if you decline it and an uninsured driver hits one of your cars. The answer: you have no coverage for your injuries or your passengers' injuries from that collision unless you carry UM coverage on the vehicle that was hit.
Arizona law requires only liability insurance: $25,000 per person, $50,000 per accident for bodily injury, and $15,000 for property damage. The state does not mandate uninsured motorist coverage, personal injury protection, or medical payments coverage. Carriers must offer UM coverage when you buy a policy, but you can decline it in writing. Once declined, you carry the full financial risk when an uninsured driver injures you or your passengers.
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Get Your Free QuoteArizona Uninsured Drivers
10.6%
One in ten drivers on Arizona roads carries no insurance. When an uninsured driver causes a collision that injures you or your passengers, their lack of coverage leaves you with no third-party claim to file unless you carry your own uninsured motorist coverage.
Insurance Information Institute, 2023
What Uninsured Motorist Coverage Pays
Uninsured motorist coverage pays for bodily injury to you and your passengers when an at-fault driver has no liability insurance. It covers medical bills, lost wages, pain and suffering, and other injury-related damages up to your UM policy limit. Arizona is a fault state: the at-fault driver's liability insurance normally pays your injury claim. When that driver has no insurance, your UM coverage steps in as a substitute.
UM coverage does not pay for damage to your vehicle. Property damage from an uninsured driver is covered under collision coverage if you carry it, or you pay out of pocket if you don't. UM coverage is strictly for bodily injury. Some states offer uninsured motorist property damage coverage; Arizona does not.
Underinsured motorist coverage is a companion product that pays when the at-fault driver carries liability insurance but their limit is too low to cover your injuries. Arizona carriers typically bundle UM and UIM together as a single coverage with one combined limit. When you see a UM/UIM line item on your policy, it covers both scenarios: no insurance and insufficient insurance.
Declining UM coverage means you have no injury protection when an uninsured driver hits you. You cannot file a claim against a driver who has no policy.
How UM Coverage Applies Across Multiple Vehicles
Each vehicle on your policy can carry a different UM limit, or you can decline UM on some vehicles and carry it on others. The truck's limit does not stack on top. The vehicle that was struck governs the coverage.
Most carriers require you to select the same UM limit across every vehicle on the policy, or decline it on all vehicles. A few allow per-vehicle UM limits, but that structure is uncommon. When you add a third or fourth vehicle mid-term, the carrier will ask whether you want UM coverage on the new vehicle at the same limit as your existing cars. If you declined UM when you opened the policy, the new vehicle is added without UM unless you affirmatively request it.
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Stacking and Non-Stacking UM Limits
Arizona allows UM stacking, which means you can combine the UM limits from multiple vehicles on your policy to cover a single injury claim. Non-stacking UM limits you to the single highest per-person and per-accident limit on your policy, regardless of how many vehicles you insure.
Stacking costs more. Carriers charge a higher premium for stacked UM coverage because the potential payout is larger. When you request a quote for multiple vehicles, the carrier will ask whether you want stacked or non-stacked UM. The difference in premium varies by household size and vehicle count, but stacking typically adds 15 to 30 percent to the UM portion of your premium.
Stacking applies only when you are injured as a driver or passenger in one of your own insured vehicles, or as a pedestrian struck by an uninsured driver. It does not apply when you are driving someone else's car. The stacking election you make applies to every vehicle on the policy; you cannot stack some vehicles and leave others non-stacked.
Arizona Liability Minimum
$25,000 / $50,000
Arizona requires $25,000 per person and $50,000 per accident in bodily injury liability coverage. Many at-fault drivers carry only this minimum. When their limit is exhausted and your injuries exceed it, underinsured motorist coverage pays the difference up to your UIM limit.
Arizona Revised Statutes § 28-4009
Choosing a UM Limit for Multiple Vehicles
Your UM limit should match or exceed your liability limit. The liability limit you chose reflects the injury severity you're willing to cover when you cause a collision; the same severity applies when someone else causes one and has no insurance to pay you.
Households insuring multiple vehicles face higher collision exposure simply because more cars are on the road more hours per day. A family with three vehicles driven by three household members has three times the statistical exposure to an uninsured-driver collision compared to a single-car household. Declining UM coverage or carrying a low limit multiplies that unprotected exposure across every vehicle and every driver.
Compare Carriers Writing UM Coverage in Arizona
Every carrier licensed to write auto insurance in Arizona must offer uninsured motorist coverage, but UM premium varies significantly by carrier. State Farm, Geico, Progressive, Allstate, Farmers, and USAA all write UM coverage in Arizona with stacking available. Non-standard carriers including Acceptance, Bristol West, Dairyland, GAINSCO, Infinity, Kemper, The General, and National General also offer UM coverage and serve households managing multiple vehicles.
When you compare quotes for a multi-vehicle policy, request the same UM limit from every carrier so the comparison is apples-to-apples. Specify your UM preference up front and compare the total premium including UM, liability, collision, and comprehensive across the full household.