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Arizona Auto Insurance & Crash Law · Citizen Guide 18
Crash Investigation
A crash report records an investigation; it does not replace one. Arizona crash reconstruction should preserve the scene, witnesses, vehicles, digital records and institutional evidence before those sources disappear, then test each fault theory against the complete record.
Build the investigation from four evidence layers
Vehicle positions, roadway, debris, markings, traffic controls, visibility and environmental conditions.
Drivers, passengers, independent witnesses, first responders and investigators.
Physical damage, EDR, telematics, cameras, phones, apps, GPS and onboard systems.
Police, businesses, governments, employers, fleets, TNCs, traffic systems and medical/toxicology records.
At the scene, preserve evidence without sacrificing safety
People come first. Evidence collection should never create another traffic hazard.
Arizona imposes immediate duties after qualifying crashes
Information and assistance
Drivers must provide specified identity and vehicle information and render reasonable assistance to injured persons when required.
Immediate notice
A crash resulting in injury or death requires immediate notice to the appropriate local police, sheriff or highway patrol office.
Obtain the Arizona crash report—but then obtain the evidence behind it
Under §28-667, a law-enforcement officer or qualifying public employee investigating a crash must complete a written accident report when the collision results in:
- bodily injury;
- death;
- more than $2,000 in property damage; or
- issuance of a citation.
Lower-damage crashes investigated by police can require a partial report even when there is no injury, death or citation.
Compare the report with its source evidence
Narrative
Which facts were personally observed and which came from another speaker?
Diagram
Is it approximately illustrative or based on actual measurements?
Witness list
Did the report capture everyone who saw the crash?
A police report can contain admissible evidence without making every line automatically admissible
Arizona Rule of Evidence 803(8) recognizes a public-record exception that can apply in civil cases to observations and factual findings from legally authorized public investigations.
But separate evidentiary issues can remain for:
- embedded witness statements
- expert opinions
- ultimate-cause opinions
- foundation
- trustworthiness
- hearsay within hearsay
Photograph the crash as a system
Roadway context
Intersection, traffic lanes, approach paths, signals, sight lines and overall resting positions.
Vehicle relationships
Relative positions, debris fields, tire marks and roadway evidence.
Physical detail
Vehicle deformation, lamps, tires, gouges, fluids, restraint systems and other details.
Do not forget the approach path
- 100–300 feet before impact
- driver sight line
- signs
- signals
- lane markings
- driveways
- vegetation
- parked vehicles
- construction
- grade / curvature
- nearby cameras
Independent witnesses can disappear faster than physical evidence
Record reliable contact information when voluntarily available and note:
Observation point
Where was the witness when the relevant event occurred?
Actual perception
What did the witness personally see or hear?
Duration
Did the witness see the entire approach or only the impact?
Obstructions
Was anything blocking the witness's line of sight?
The vehicle itself can be a primary evidence repository
Before repair, total-loss disposal or salvage, determine whether the vehicle requires inspection.
Structure
Crush, deformation, contact pattern and intrusion.
Mechanical
Brakes, tires, steering, suspension and lighting.
Restraints
Seat belts, airbags and occupant-protection systems.
Electronics
EDR, ADAS, infotainment, GPS, cameras and telematics.
Event data can provide an independent electronic snapshot
A qualifying EDR can preserve information generated immediately before and during a crash event.
Pre-crash operation
Depending on the module, information can include indicated speed, throttle/accelerator and braking.
Crash severity
Standardized data can include longitudinal delta-V and event timing.
Occupant systems
Some standardized data concern belt status, airbags and multiple events.
Vehicle black-box data is protected by federal privacy law
The federal Driver Privacy Act of 2015 states that qualifying EDR data is the property of the vehicle owner or, for a leased vehicle, the lessee.
Access by another person generally requires a statutory basis such as:
- owner or lessee consent
- court authorization
- administrative authorization
- specified federal safety investigation
- emergency medical-response purpose
- qualifying traffic-safety research
Modern crash evidence extends far beyond the EDR
Telematics
Connected vehicle, fleet or manufacturer systems may preserve location and operational information.
Infotainment
Navigation, pairing and device-interaction information can sometimes be relevant to distraction or trip history.
ADAS
Driver-assistance modules can become important when automatic braking, lane assistance or collision-warning systems are disputed.
Phone and app evidence must be obtained lawfully
A phone can contain evidence concerning:
- call activity
- text activity
- navigation
- location
- photographs
- rideshare status
- delivery status
- application timestamps
Search outward for video before it is overwritten
Potential sources include:
Businesses
Gas stations, stores, parking facilities, hotels and commercial buildings.
Public systems
Traffic cameras, municipal systems, buses and law-enforcement cameras.
Private cameras
Homes, doorbell systems, dash cameras and witnesses' vehicle cameras.
A red-light dispute can be investigated beyond witness memory
Where material, request or preserve:
- signal timing plan
- phase sequence
- yellow interval
- all-red interval
- detector data
- controller information
- maintenance history
- malfunction reports
- video
- roadway plans
Serious crashes can generate toxicology evidence
A.R.S. §28-673 establishes an implied-consent testing system for specified crashes causing death or serious physical injury when its statutory probable-cause or citation conditions are met.
A.R.S. §28-668 separately addresses alcohol testing of a deceased driver in specified circumstances.
Police evidence
Observations, body-camera footage, field testing and warrant records.
Laboratory evidence
Blood, breath, urine or other qualifying toxicology evidence, interpreted according to the applicable law and science.
Expand the evidence list when a special vehicle system is involved
Fleet / truck evidence
ELD, ECM, dispatch, cargo, driver qualification, maintenance, GPS and employer records.
TNC evidence
Log-on, ride request, acceptance, pickup, GPS and trip termination determine both facts and insurance phase.
Agency evidence
Dispatch, CAD, body camera, dash camera, radio, GPS, pursuit and internal review materials.
Mechanical-failure allegations require preservation before repair
If a driver says the brakes, steering, tire or other component failed, preserve:
- vehicle itself
- failed component
- maintenance history
- repair invoices
- prior complaints
- recall information
- warning lights
- diagnostic codes
- aftermarket modifications
- photographs before disassembly
Arizona litigants have a duty to preserve relevant evidence
Souza v. Fred Carries Contracts recognizes the litigation duty to preserve relevant evidence.
McMurtry v. Weatherford Hotel explains that matters such as bad faith, intentional destruction and prejudice can affect the sanctions analysis.
Preservation requests should identify evidence with precision
What event?
Date, time, location, drivers, vehicles and claim identifiers.
What evidence?
Vehicle, video, EDR, app, GPS, telematics, dispatch or another identified evidence category.
What time range?
Define a reasonable window around the crash rather than requesting unrelated years of data.
What preservation?
Request that relevant evidence not be erased, overwritten, repaired, sold, altered or destroyed.
Evidence has a life cycle
Arizona crash investigation workflow
Crash investigation evidence checklist
- police crash report
- supplemental police reports
- officer notes
- scene photographs
- vehicle photographs
- witness contact information
- witness statements
- 911 records
- dispatch records
- body-camera video
- dash-camera video
- traffic-camera video
- business surveillance
- residential surveillance
- vehicle EDR
- ECM data
- vehicle telematics
- infotainment data
- ADAS data
- GPS data
- phone records
- app records
- TNC records
- commercial ELD records
- fleet dispatch
- driver logs
- vehicle maintenance
- repair records
- tire records
- recall information
- traffic-signal data
- roadway plans
- weather records
- toxicology evidence
- tow-yard information
- salvage-auction information
- preservation correspondence
- chain-of-custody documentation
- reconstruction reports
Common Arizona crash-investigation mistakes
“The police report already proves fault.”
It is important evidence, but comparative fault requires evaluation of the underlying and later-discovered evidence.
“The insurance company will preserve the totaled vehicle.”
Do not assume that. Determine possession and disposition plans immediately.
“We can look for video later.”
Many video systems overwrite automatically. Search and preserve early.
“EDR speed decides everything.”
EDR information must be validated and interpreted with the complete reconstruction.
“We can download the other car's black box ourselves.”
Federal privacy law restricts access. Use consent or other lawful authority.
“Taking screenshots is enough to preserve digital evidence.”
Preserve original files and metadata where material and technically possible.
“A public-record request preserves a government claim.”
No. Evidence requests do not replace Arizona's 180-day notice-of-claim requirement.
“A citation means the other driver is 100% at fault.”
A citation is evidence concerning an alleged traffic violation; it does not replace Arizona's complete comparative-fault analysis.
Arizona authority map
Frequently asked questions
Does Arizona require a police report for every crash?
Arizona requires investigating officers to complete different levels of accident reporting depending on injury, death, citation and property damage. Section 28-667 should be reviewed for the particular situation.
When is a full Arizona law-enforcement accident report required?
Under §28-667, an investigating officer or public employee must complete the written report when the crash results in bodily injury, death, more than $2,000 in property damage, or issuance of a citation.
Can a person involved in the crash obtain an unredacted report?
Section 28-667 generally requires the agency, on request and subject to statutory limitations, to provide the unredacted report to an involved person or an owner of an involved vehicle, among other specified recipients.
Does the police report determine who is legally at fault?
No. The report can be important evidence, but Arizona's civil comparative-fault determination depends on the complete admissible evidence and governing law.
Should the cars always remain exactly where they stopped?
No. Safety and Arizona's quick-clearance law matter. Section 28-674 can require safe movement of drivable vehicles from qualifying roadways where serious injury or death is not apparent.
What is an EDR?
An event data recorder is a vehicle system capable of recording specified information associated with a crash event. Depending on the vehicle, data can include speed, braking, throttle, delta-V and restraint information.
Who owns EDR data?
Under the federal Driver Privacy Act, qualifying EDR data belongs to the vehicle owner or, for a leased vehicle, the lessee.
Can I download the other driver's EDR?
Not merely because a crash occurred. Federal law restricts retrieval by persons other than the owner or lessee unless consent, court authority or another statutory exception applies.
How quickly should surveillance video be sought?
Immediately. Businesses, homes, traffic systems and vehicles can overwrite video automatically, sometimes long before the liability claim is fully investigated.
What if the insurance company wants to salvage my vehicle?
Determine first whether the vehicle, EDR, mechanical components or other evidence needs inspection or preservation. Once a vehicle is auctioned or dismantled, important evidence can be impossible to recreate.
Can evidence destruction affect an Arizona lawsuit?
Yes. Arizona litigants have a duty to preserve relevant evidence, and courts can impose appropriate sanctions where evidence is improperly destroyed or lost.
Does Arizona recognize a separate lawsuit just for destroying evidence?
Arizona does not recognize a separate first-party spoliation tort. Courts generally address a litigant's preservation failures through evidentiary and litigation sanctions.
When is an accident reconstruction expert useful?
Expert reconstruction can be particularly useful in serious-injury, fatal, commercial, rollover, pedestrian, bicycle, multi-impact, visibility, mechanical-failure or heavily disputed comparative-fault cases.
Preserve first. Analyze second.
Secure the scene evidence, witnesses, vehicles, video and electronic records before they disappear. Then synchronize the physical, human and digital evidence into one timeline and apply Arizona's fault rules to what the evidence actually demonstrates.