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Arizona Auto Insurance & Crash Law · Citizen Guide 17
Comparative Fault
Arizona uses pure comparative negligence and generally several-only liability. A claimant's ordinary fault reduces rather than automatically eliminates recovery, while defendants may seek allocation to other defendants, settling actors and properly disclosed nonparties who also contributed to the injury.
Arizona is a pure comparative-negligence state
Under A.R.S. §12-2505, ordinary claimant negligence reduces recovery according to the claimant's percentage of responsibility rather than creating a 50% or 51% cutoff.
| Claimant fault | Total damages | Illustrative recovery |
|---|---|---|
| 0% | $500,000 | $500,000 |
| 20% | $500,000 | $400,000 |
| 40% | $500,000 | $300,000 |
| 90% | $500,000 | $50,000 under ordinary comparative-negligence principles. |
The claimant's own driving is part of the liability investigation
A defendant or liability insurer may argue that the injured person contributed to the crash or injury.
Speed
Was the claimant traveling too fast for the applicable law or conditions?
Right of way
Did the claimant enter the intersection or roadway contrary to an applicable duty?
Attention
Phone use, distraction, fatigue or failure to perceive visible danger can become fault arguments.
Impairment
Alcohol or drug impairment can become relevant where supported by admissible evidence and causation.
Vehicle operation
Braking, lane position, lighting, signaling and evasive action can matter.
Causation
Even negligent conduct must have caused or contributed to the injury before it becomes comparative fault.
Arizona gives the jury an unusually important constitutional role
Arizona Constitution article XVIII, §5 provides that contributory negligence and assumption of risk must be left to the jury.
Section 12-2505 repeats that principle.
Gunnell v. Arizona Public Service Co. reiterates that the jury remains the arbiter of the contributory/comparative negligence defense under Arizona's constitutional structure.
Willful or wanton claimant conduct follows a special Arizona rule
Section 12-2505 states that a claimant who intentionally, willfully or wantonly caused or contributed to the injury has no right to ordinary comparative negligence.
In Williams v. Thude, involving alleged willful or wanton claimant conduct, the Arizona Supreme Court explained that the jury should not simply perform the ordinary comparative-percentage calculation.
Percentage reduction
Claimant fault ordinarily reduces damages proportionately.
Special constitutional treatment
The ordinary comparative-fault benefit is unavailable, while the jury retains Arizona's constitutional role concerning the contributory- negligence defense.
Arizona generally makes each defendant responsible only for that defendant's share
A.R.S. §12-2506 abolished ordinary joint and several liability in personal injury, property-damage and wrongful-death actions, subject to specified exceptions.
Example
| Actor | Fault | Share of $1,000,000 damages |
|---|---|---|
| Claimant | 20% | $200,000 reduction |
| Driver A | 50% | $500,000 |
| Driver B | 20% | $200,000 |
| Nonparty contractor | 10% | No judgment against that nonparty merely from allocation. |
The jury can allocate fault to someone who is not a defendant
Section 12-2506(B) instructs the factfinder to consider the fault of all persons who contributed to the injury regardless of whether the person was or could have been named as a party.
Potential nonparties in crash litigation
- another driver
- vehicle owner
- employer
- road contractor
- government entity
- vehicle manufacturer
- repair facility
- maintenance company
- settling tortfeasor
- immune employer
- criminal actor
- later medical provider
Nonparty fault requires procedural notice after suit is filed
Arizona Rule of Civil Procedure 26(b)(5) currently requires a party alleging nonparty fault to serve a notice generally no later than:
The notice must disclose
Identity
Who is the person or entity allegedly at fault?
Location
Where can that person or entity be located?
Supporting facts
What facts support the allegation that the nonparty caused or contributed to the injury?
Even an immune actor may appear on the verdict form
Dietz v. General Electric involved an employer whose employee could not sue the employer in tort because of workers' compensation immunity.
That distinction matters because:
Can plaintiff collect from this actor?
Possibly no because a separate immunity or legal bar applies.
Can this actor still affect percentages?
Potentially yes if Arizona's nonparty-at-fault requirements are satisfied.
Arizona can compare negligent and intentional wrongdoing
Hutcherson v. City of Phoenix demonstrates the breadth of Arizona's comparative-fault system.
The case involved:
- negligent handling of a 911 call by a City employee; and
- intentional murder by another person.
Arizona permitted the jury to allocate fault between the negligent actor and the intentional tortfeasor.
The jury can evaluate
- degree of wrongful conduct
- causal contribution
- foreseeability
- ability to prevent the harm
- opportunity for avoidance
- responsibility assumed by each actor
Arizona retains narrow exceptions to several-only liability
Section 12-2506(D) identifies circumstances in which one party can be responsible for another person's fault.
Acting in concert
The actors consciously agreed on a common plan to commit an intentional tort and actively participated in it.
Agent or servant
Traditional vicarious-liability relationships can make one party responsible for another person's fault.
FELA
The statute separately recognizes liability arising from duties under the Federal Employers' Liability Act.
Vicarious liability is not the same as allocating separate fault to an employer
Wiggs v. City of Phoenix explains that a party whose liability is purely vicarious has no independent percentage of wrongdoing merely because another person's fault is legally imputed to it.
Young v. Beck similarly confirms that Arizona's family purpose doctrine survived adoption of UCATA because it is a vicarious-liability doctrine.
Piner preserves recovery when multiple tortfeasors cause one indivisible injury
Some injuries cannot reliably be divided by physical causation.
Example
A person suffers two collisions several hours apart. Both aggravate the same spinal condition. Medical testimony cannot reliably identify what percentage of the final physical condition came from each crash.
Later medical negligence can enter the comparative-fault case
Cramer v. Starr arose from a rear-end automobile crash followed by spinal surgery that allegedly worsened the passenger's condition.
The original driver named the surgeon as a nonparty at fault.
At the same time, the original driver may remain legally responsible for foreseeable enhanced harm caused by treatment reasonably required because of the original injury.
A settling tortfeasor can still matter to percentage allocation
Section 12-2506(B) expressly permits the factfinder to consider the fault of a nonparty with whom the plaintiff has entered into a settlement agreement.
Settlement question
What claims were resolved, for how much, and against whom?
Fault question
What percentage of legal responsibility should still be assigned to the settling actor when allocating the whole?
Fault percentages must be built from evidence, not labels
Statements such as:
- “the police said he was at fault”;
- “the insurance company assigned 80/20”;
- “she received the citation”;
- “the damage was on the rear bumper”;
may identify evidence worth investigating, but they do not replace a complete civil fault analysis.
Build the crash from objective evidence
- vehicle positions
- scene measurements
- traffic signals
- skid / yaw evidence
- EDR data
- vehicle telematics
- surveillance video
- dash camera
- body camera
- phone records
- GPS records
- witness statements
- vehicle damage
- roadway geometry
- weather and lighting
- traffic-control devices
- driver admissions
- expert reconstruction
Arizona comparative-fault workflow
Comparative-fault evidence checklist
- police crash report
- supplemental reports
- citations
- scene photographs
- scene measurements
- vehicle photographs
- vehicle inspections
- EDR downloads
- telematics
- GPS data
- cell-phone records
- surveillance footage
- dash-camera footage
- body-camera footage
- witness statements
- traffic-signal records
- roadway maintenance records
- driver employment records
- vehicle maintenance records
- product evidence
- medical causation evidence
- later medical-treatment evidence
- settlement agreements
- Rule 26(b)(5) notices
- nonparty-fault disclosures
- expert reconstruction reports
Common Arizona comparative-fault mistakes
“If I am more than 50% at fault, I recover nothing.”
Not under ordinary Arizona comparative negligence. Arizona uses a pure system without an ordinary 50% or 51% cutoff.
“The defendant must pay the entire judgment.”
Usually not. Arizona generally uses several-only liability under §12-2506.
“Someone immune from suit cannot be assigned fault.”
Dietz demonstrates that an immune employer can nevertheless be considered in comparative allocation.
“Intentional conduct cannot be compared with negligence.”
Hutcherson rejects that categorical rule under Arizona's system.
“An indivisible injury means all defendants are jointly liable.”
Piner preserves the indivisible-injury rule but still requires several liability based on comparative percentages.
“A late medical error is automatically all the original driver's responsibility.”
Cramer permits comparative allocation to a negligent medical provider where the evidence supports it.
“Two negligent people were acting in concert.”
Not under §12-2506's definition. Acting in concert requires agreement to pursue an intentional tort.
“The insurance adjuster's percentage controls the lawsuit.”
No. Civil fault allocation ultimately depends on admissible evidence and Arizona law.
Arizona authority map
Frequently asked questions
Is Arizona a pure comparative-fault state?
Yes for ordinary negligence. A claimant's negligence generally reduces damages proportionately rather than barring the claim at a 50% or 51% threshold.
If I am 60% responsible for an Arizona crash, can I still recover?
Under ordinary comparative-negligence principles, yes. The recovery would generally be reduced by the percentage of claimant fault that proximately caused the injury.
If I am 90% at fault, can I still recover?
Ordinary Arizona comparative negligence can permit recovery of the remaining 10% of compensable damages. Different rules can apply to intentional, willful or wanton claimant conduct.
Does each defendant have to pay the entire judgment?
Generally no. Section 12-2506 ordinarily limits each defendant to the portion of damages corresponding to that defendant's percentage of fault.
Can the jury blame someone who was never sued?
Potentially. Arizona permits allocation to properly identified nonparties at fault, subject to §12-2506 and Rule 26(b)(5).
Can fault be allocated to someone who cannot legally be sued?
In some circumstances, yes. Dietz allowed allocation to an employer protected from the employee's tort claim by workers' compensation immunity.
What is the deadline for identifying a nonparty at fault?
Current Arizona Rule of Civil Procedure 26(b)(5) generally requires the notice within 150 days after the party files its answer, subject to the rule's exceptions.
Can negligent conduct be compared with intentional misconduct?
Yes. Hutcherson holds that Arizona's fault-allocation system can compare negligent and intentional wrongful conduct.
What if two crashes caused one injury that doctors cannot divide?
Piner permits use of the indivisible-injury doctrine. The jury can determine total damages and allocate comparative fault among the responsible actors rather than requiring impossible physical apportionment.
Can an original crash driver blame a later negligent doctor?
Potentially. Cramer permits later medical-provider negligence to be considered as nonparty fault if supported by evidence, while the original driver may still remain responsible for foreseeable enhanced harm.
When does joint responsibility still exist?
Section 12-2506 preserves specified exceptions involving acting in concert, agent/servant relationships and FELA liability. Vicarious liability doctrines also require careful separate analysis.
Does “acting in concert” mean two drivers were both negligent?
No. Arizona defines acting in concert as a conscious agreement to pursue a common plan to commit an intentional tort and active participation in it.
Does a police citation determine comparative fault?
No. A citation can be relevant evidence, but civil comparative fault is determined from the entire evidentiary record and the governing legal duties.
Build the entire fault map—not just a theory against one driver.
Identify every duty, breach and causal actor. Separate claimant fault, defendant fault, nonparty fault and vicarious responsibility. Then calculate total damages and apply Arizona's pure comparative-negligence and several-liability rules to the complete 100% allocation.