Who determines fault in an Arizona car accident? Three different parties assess it at different stages — the investigating officer, the insurance companies, and ultimately, if a case goes that far, a jury — and none of the first two is final. Arizona's comparative negligence law also means fault is rarely all-or-nothing.
The Officer's Assessment
The responding officer documents the scene, takes statements, and may note contributing factors or issue citations. That assessment matters — insurers read it, and it preserves the earliest account — but it isn't binding in a civil claim. Officers usually didn't see the crash, and a citation (or the absence of one) doesn't decide who pays for what.
The Insurers' Assessment
Each insurer investigates and takes a position on fault, because fault determines which company pays and how much. Insurers weigh the crash report, statements, photos, vehicle damage patterns, and any available footage. Their fault positions are negotiating positions — well-informed ones, usually, but positions that evidence can and does move. When insurers disagree with each other, or with the injured person, the claim doesn't stall forever: it moves toward resolution through negotiation or, if needed, litigation.
The Jury's Assessment
If a claim becomes a lawsuit and doesn't settle, a jury makes the actual legal determination — assigning percentages of fault to everyone involved. Very few claims travel that far, but every serious claim is evaluated in that light: what would the evidence show a jury? That question quietly governs the negotiations that resolve most cases.
Arizona's Percentage System
Under A.R.S. § 12-2505, Arizona follows pure comparative negligence. Fault gets divided in percentages, and a claimant's recovery is reduced by their share — a person found 20 percent at fault recovers 80 percent of their damages. Unlike some states, Arizona doesn't cut recovery off at any threshold: even a person found mostly at fault can recover the remaining share. That's why early, casual statements about fault deserve care, and why "partly my fault" is never a reason to assume there's no claim.
What Actually Moves Fault Determinations
Evidence — the same short-lived evidence that rewards early action: camera footage before it's overwritten, witness accounts before memories fade, vehicle damage before repairs, scene photos. The crash report guide covers the first document in that stack, and the complete after-accident guide covers preserving the rest. When fault is disputed, a consultation — free at most firms, including ours — is most valuable early, while that evidence still exists.