Arizona Is an At-Fault State

Almost every coverage decision on this site traces back to one fact about Arizona law, and it is worth setting out properly rather than in passing. Arizona is an at-fault state. Whoever causes a crash owes what it costs. That sounds simple, and the headline is — but the mechanics underneath decide who actually gets paid, how much, and by when. Here is how fault works here, including a rule that makes Arizona unusually generous to drivers who were partly to blame.

The rule

At-faultThe cause pays

Fault split

Pure comparativeARS 12-2505

Deadline

2 years180 days vs government

The catch

Limits cap paymentNot what they owe

What does at-fault actually mean?

Short answerThe driver who caused the crash owes the damage, and you claim against their insurer.

The cleanest way to hold it is by contrast with the alternative.

In a no-fault state, each driver's own policy pays their medical costs regardless of who caused the accident. Fault still matters for property damage and serious injury, but the baseline medical coverage is yours and it responds automatically.

In an at-fault state like Arizona, there is no such automatic layer. The responsible driver owes the resulting injuries and property damage, and you pursue their liability insurance. That's called a third-party claim — you're the third party to a contract between the other driver and their insurer.

Three consequences that shape everything else:

Fault has to be established. Somebody investigates, and the evidence decides. This is why documentation at the scene matters far more here than most drivers assume.

You're negotiating with a company that isn't yours. The other driver's insurer owes its duties to its own policyholder, not to you.

Their limit caps their insurer, not their obligation. The shortfall above the policy limit is owed personally by the at-fault driver — which is only useful if they have assets.

How does Arizona split the blame?

Short answerPure comparative negligence — you can be 99% at fault and still recover 1%.

This is the part that genuinely differs from most of the country, and it works in your favour.

Run the arithmetic on a real split. Your damages are $100,000 and you're found 30% responsible: you recover $70,000. Found 70% responsible: you recover $30,000. In most states, that second scenario pays you nothing at all.

Two practical implications.

Don't write off a claim because you think you caused it. Partial fault reduces a recovery here; it doesn't eliminate one.

Percentages are negotiated, and the negotiation is real money. The gap between being assessed at 40% and 60% on a six-figure claim is enormous, which is precisely why the other driver's insurer has an incentive to attribute as much fault to you as the evidence allows.

Which policy pays for what?

Short answerIt depends entirely on who was at fault — which is the whole point of an at-fault state.

After a crash there are usually several possible sources of payment, and which one responds turns on fault. This is the table worth understanding before you need it.

Two rows deserve attention. Notice that your own collision coverage is what repairs your car when you caused the crash — liability pays other people, never you. A driver carrying liability only has no way to repair their own vehicle in an at-fault accident.

And notice how often the answer is "your UM coverage." In a state where a substantial share of drivers carry nothing, that column does more work than it should. Raquel prices both sides of this together as part of a Tucson car insurance review, and prices Tucson home insurance alongside it where the household needs both, and for households with assets an umbrella above the home and auto extends the liability side further.

What are the deadlines?

Short answerGenerally two years — but only 180 days if a government vehicle is involved.

Deadlines end more valid claims than bad facts do.

The general rule. Under ARS 12-542, you generally have two years from the date of the crash to file suit for personal injury or property damage.

The exception that catches people. If a government entity is involved — a city vehicle, a county truck, a transit bus, a school district van — ARS 12-821.01 requires a notice of claim served within 180 days of the incident, with a one-year limit to file suit. Six months, not two years.

That distinction matters in Tucson specifically, where city, Pima County, university and transit vehicles are a routine part of traffic. A crash that feels like any other can carry a deadline a quarter as long, and nobody at the scene will mention it.

Note also that these are deadlines for legal action, not for reporting to your own insurer — which should happen immediately regardless, because late notice can jeopardize your own coverage.

What if their insurance isn't enough?

Short answerThis is the weak point of at-fault systems — and it's why UM/UIM matters here.

Here is where Arizona's at-fault rule and Arizona's other characteristics collide badly.

The state minimum is 25/50/15 — $25,000 of bodily injury per person and $15,000 of property damage. A driver carrying exactly that is fully legal and badly underinsured for any serious injury. When their limit is exhausted, the balance is legally theirs, but a driver at the statutory floor frequently has nothing worth pursuing.

Add the second factor: roughly one in eight Arizona drivers carries no insurance at all. In an at-fault state, a crash caused by an uninsured driver leaves you with a valid claim against someone who cannot pay it.

The answer is on your own policy. Uninsured and underinsured motorist coverage is a first-party claim — against your own insurer, under your own contract — which sidesteps the entire problem. ARS 20-259.01 requires Arizona insurers to offer it in writing at limits not less than your liability limits. It isn't mandatory to buy, which is why so many drivers declined it years ago without registering what they were giving up.

For a household with assets or income to protect, an umbrella policy extends both sides of this — your liability if you cause the crash, and, by endorsement, your UM/UIM if someone else does.

What should you do after a crash?

Short answerDocument, report, and don't concede percentages.

In an at-fault state, the evidence at the scene decides who pays. That makes the first twenty minutes disproportionately valuable.

Photograph before anything moves. Vehicle positions, damage from several angles, road conditions, signals, signage, skid marks. Once cars are moved to the shoulder that record is gone permanently.

Exchange information properly. Name, address, phone, insurer and policy number, plus the plate and a photograph of their insurance card. A policy number written down wrong is a claim that stalls for weeks.

Get a police report. An independent account carries weight that a driver's recollection does not, especially where fault is disputed.

Note the conditions. Time of day, weather, whether the sun was low, whether a signal was obscured by a tree. In a comparative-fault state these details shift percentages, and none of them are recoverable a week later.

Collect witness details. Witnesses vanish within minutes and are near-impossible to trace afterward. A name and a phone number frequently decides a contested claim.

Report to your own insurer promptly even when you were not at fault, because your own coverages may be involved and late notice can jeopardize them.

Don't admit fault or guess at percentages. An apology is human and it is not a legal finding — but it can be used. Fault gets apportioned after investigation, and you don't have enough information at the roadside to concede anything.

Be careful with early settlement offers. Injuries that seem minor can develop, and a signed release closes the claim permanently. For anything serious, that's a conversation for an attorney — not for your agent and not for an article.

The Bottom Line

Arizona's at-fault rule means the driver who caused a crash owes the damage, and you claim against their insurer rather than your own. Two details make the local version distinctive. Arizona applies pure comparative negligence under ARS 12-2505, so partial fault reduces a recovery without ever barring it — you can be 70% responsible and still collect 30%, which most states would not allow. And the deadlines are shorter than they look: generally two years, but only 180 days to serve a notice of claim if a government vehicle is involved.

The weakness of any at-fault system is that it depends on the responsible driver being able to pay, and Arizona pairs that system with one of the highest uninsured driver rates in the country. That is the entire argument for carrying uninsured and underinsured motorist coverage on your own policy, at limits that match your liability. Raquel Jimenez Insurance in Tucson will check whether yours does, at no charge. Call (520) 889-5766.

Related Questions Arizona Drivers Ask

Last reviewed by Raquel Jimenez on August 20, 2026. Arizona's pure comparative negligence rule is ARS 12-2505; the general two-year limitation period for personal injury and property damage is ARS 12-542; the 180-day notice of claim requirement for public entities is ARS 12-821.01. Minimum liability limits are set by ARS 28-4009, and the requirement that insurers offer uninsured and underinsured motorist coverage in writing is ARS 20-259.01. The uninsured driver share reflects Insurance Research Council estimates as commonly cited for Arizona. This is general information, not legal advice; for a specific claim, consult an Arizona attorney.