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Crash Investigation & Evidence Preservation in Washington

A crash investigation should reconstruct what happened from evidence—not simply repeat what one driver, an adjuster or even the initial police report concludes. Vehicle positions, witnesses, photographs, roadway marks, video, electronic vehicle data, phone and app records, medical evidence and the physical damage can each preserve a different part of the event. The most valuable evidence is often the evidence most likely to disappear first.

Current-law review: Sept. 13, 2026 RCW 46.52 collision duties $1,000 reporting threshold Vehicle-recording-data protections
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At the Scene Washington Reporting Rules Police Investigation Collision Report Witnesses Physical Evidence Video & Digital Evidence Vehicle Data / EDR Phones & Apps Preserve the Vehicles Crash Reconstruction Medical Causation Citizen Workflow Authorities

The investigation begins with safety, identification and preservation

The first responsibility after a collision is not proving a lawsuit. It is preventing additional injury and obtaining appropriate emergency help.

First

Protect people

Call 911 when injury, danger or other circumstances warrant emergency response. Do not create a second collision while trying to document the first.

Second

Identify everyone

Drivers, owners, passengers, witnesses, law-enforcement officers, vehicles and insurers should be identified.

Third

Preserve what will disappear

Vehicle positions, debris, marks, weather, lighting, traffic signals and independent witnesses can change or disappear within minutes.

Evidence priority: preserve transient evidence first and reconstruct the legal theories later.

Washington requires drivers to stop, exchange information and assist injured people

RCW 46.52.020 governs collisions involving injury, death, attended vehicles and other property.

Depending on the circumstances, the driver must provide information including:

  • name;
  • address;
  • insurance company;
  • insurance policy number;
  • vehicle license number; and
  • driver's license for inspection.

The statute also requires reasonable assistance to an injured person, including arranging transportation for medical treatment when treatment is apparently necessary or requested.

Do not turn the roadside exchange into an interrogation. Obtain identifying information and preserve observations. Statements made while people are shocked, injured or confused may later prove incomplete or inaccurate.

For a property-damage-only crash, Washington generally requires moving the vehicles out of active traffic

RCW 46.52.020 directs drivers in a collision involving only property damage to move the vehicles as soon as possible away from active roadway lanes and related traffic areas to a suitable location.

Washington expressly says that moving the vehicle does not affect fault.

If it can be done safely before movement, quick photographs showing the original resting positions and surrounding roadway can be useful. But documentation should never take priority over immediate safety or lawful directions from police or transportation personnel.

Washington has a separate collision-reporting requirement

RCW 46.52.030 requires a report for qualifying collisions involving:

  • injury;
  • death; or
  • property damage to any one person's property at or above the current reporting threshold.
Current Washington property-damage reporting threshold: $1,000.

WAC 446-85-010 establishes the current $1,000 threshold.

If a law-enforcement officer investigates a qualifying collision and submits the required investigator's report, the driver's separate reporting obligation under RCW 46.52.030 is generally satisfied through that officer reporting process.

Otherwise, the driver generally must make the required written report within four days.

Washington State Patrol maintains an online civilian collision-reporting system as well as a system for requesting official collision records.

A police investigation is an important evidence source—not a substitute for an independent investigation

RCW 46.52.070 directs a Washington law-enforcement officer with facts concerning a collision to make a report as fully as the facts in the officer's possession permit.

A useful police investigation may identify:

  • drivers and owners;
  • passengers;
  • witnesses;
  • insurance information;
  • vehicle positions;
  • roadway conditions;
  • traffic controls;
  • apparent injuries;
  • vehicle damage;
  • possible distraction;
  • citations or criminal investigation; and
  • the officer's observations and investigative conclusions.
A collision report is not a civil verdict. Officers frequently arrive after the impact. Their report may be based partly on statements and information supplied by others, and civil fault can later depend on evidence the officer never obtained.

Obtain the report—but obtain the underlying facts too

Washington State Patrol maintains the statewide collision-record system. Interested persons can request collision records through the State Patrol.

RCW 46.52.083 separately requires factual data submitted by investigating officers, together with signed witness statements, to be available to the interested parties identified by statute, excluding the protected reports signed by the involved drivers.

Do not ask only for “the report.” Ask what additional factual material exists behind it.

Depending on the agency and investigation, that may include:

  • supplemental narratives;
  • scene photographs;
  • measurements;
  • diagrams;
  • signed witness statements;
  • body-worn-camera recordings;
  • dash-camera video;
  • 911 recordings;
  • dispatch / CAD records;
  • toxicology information;
  • reconstruction materials; and
  • citations or charging information.

Washington protects required driver collision reports

RCW 46.52.080 contains confidentiality and evidentiary protections for required accident reports and supplemental reports made by the reporting individual.

The statute nevertheless permits specified identifying information to be disclosed to people with a proper interest in the collision.

Do not assume every document called a “collision report” is automatically admissible at trial. Driver reports receive specific statutory protection, while police reports, witness statements and their individual contents can raise separate hearsay, foundation, opinion and other evidence issues.
The more durable approach is to preserve the underlying evidence: photographs, witness testimony, measurements, video and electronic data, rather than relying entirely on a report's ultimate conclusion.

Independent witnesses can disappear faster than physical evidence

A person who saw the collision may leave the scene before police obtain a statement.

If circumstances safely permit, preserve:

  • full name;
  • telephone number;
  • email address;
  • where the witness was located;
  • what direction the witness was facing;
  • whether the witness saw the vehicles before impact;
  • whether the witness has photographs or video; and
  • whether the witness spoke with police.
Independent observation can become especially important when both drivers later give different accounts.

Avoid coaching the witness. Preserve the witness's own observations in the witness's own words.

The physical scene can test whether the verbal accounts make sense

A disciplined investigation works outward from the physical evidence.

Evidence Possible significance
Final vehicle positions Movement, rotation, collision sequence and roadway location
Impact damage Direction and relative location of contact
Tire marks Braking, steering or loss of control
Scrapes / gouges Possible area of impact or post-impact movement
Debris field Impact area and movement after collision
Traffic signals / signs Right-of-way analysis
Lane markings Vehicle path and lane-position disputes
Sight distance Perception and reaction opportunity
Road / weather conditions Stopping distance, visibility and vehicle control
Lighting Visibility of vehicles, pedestrians and hazards
Photograph context, not merely damage. Wide roadway photographs often explain a crash better than dozens of close-ups of a damaged bumper.

A useful crash-photo sequence moves from wide to close

Photograph the overall roadway. Capture the intersection, lanes, shoulders, traffic controls and vehicle positions.
Photograph each approach. Show what each driver would have seen.
Photograph each vehicle from all sides. Preserve damage pattern and overall condition.
Photograph transient roadway evidence. Debris, marks, fluids and displaced objects may soon disappear.
Photograph identifying information. License plates, commercial markings and vehicle numbers can identify additional owners or employers.
Preserve the original files. Metadata and original resolution can matter later.

Search outward for video before it is overwritten

Many modern crashes occur within view of a camera that no one initially notices.

Potential video sources include:

  • vehicle dashcams;
  • commercial fleet cameras;
  • police body-worn cameras;
  • police dash cameras;
  • business security systems;
  • doorbell cameras;
  • parking-lot cameras;
  • transit cameras;
  • traffic-management cameras;
  • residential systems; and
  • mobile-phone recordings.
Video can be overwritten quickly. Locate the camera, identify the owner and request preservation before the normal retention cycle deletes the recording.

Modern vehicles can contain crash-relevant electronic data

Washington chapter 46.35 RCW regulates access to vehicle recording devices.

Washington defines recording devices broadly enough to include:

  • event data recorders;
  • sensing and diagnostic modules;
  • electronic control modules;
  • automatic crash-notification systems;
  • geographic information systems; and
  • other onboard systems preserving vehicle-related electronic data.

Depending on the vehicle and system, recoverable crash information may include items such as:

  • vehicle speed;
  • braking;
  • accelerator input;
  • seat-belt status;
  • airbag deployment;
  • change in velocity;
  • steering or stability-system information; and
  • event timing.
The available data varies by vehicle. Do not assume every automobile records every item or that the EDR alone can reconstruct an entire collision.

Washington restricts access to vehicle-recording data

RCW 46.35.030 generally prohibits someone other than the vehicle owner from accessing recording-device information unless a statutory exception applies.

Important exceptions include:

  • a court order;
  • civil discovery;
  • specific owner consent;
  • specified de-identified vehicle-safety research;
  • specified emergency medical purposes; and
  • authorized subscription-service use.
Preserve first; download lawfully. A preservation request can be important even when immediate access requires owner consent, discovery or a court order.

RCW 46.35.040 also requires manufacturers of vehicles equipped with recording devices to make commercially available tools capable of accessing the stored information.

Phone and app evidence can establish distraction, navigation and timing

Washington collision reports specifically collect information concerning potential driver distraction.

Depending on the facts and lawful discovery process, relevant digital evidence may include:

  • call logs;
  • text-message timing;
  • application activity;
  • navigation history;
  • rideshare status;
  • delivery-app status;
  • photographs or videos;
  • Bluetooth or vehicle connections;
  • commercial dispatch records; and
  • location or telematics data.
Privacy and discovery rules still apply. A crash does not create an unrestricted right to search another person's telephone. Preserve the relevant issue and use lawful consent, subpoena, discovery or court procedures where required.

The vehicles themselves are evidence

A severely damaged vehicle can be repaired, sold, dismantled or destroyed long before a disputed crash reaches litigation.

Potentially important vehicle evidence includes:

  • crush pattern;
  • contact marks;
  • lamp or bulb condition;
  • tires;
  • brakes;
  • steering components;
  • airbags and restraint systems;
  • seat position;
  • electronic modules;
  • dashcam systems; and
  • mechanical defects.
Before destructive repair, salvage or disposal, ask whether the vehicle may need inspection.

Washington courts consider the importance of missing evidence and the culpability surrounding its loss when addressing spoliation issues. A prompt written preservation request can help establish that important evidence was identified before it disappeared.

Commercial and government vehicles create additional evidence streams

Commercial vehicle

Business records

GPS, telematics, dashcams, electronic logs, dispatch records, inspections, maintenance records and driver qualification files may matter.

Government vehicle

Agency records

CAD, radio, bodycam, dashcam, GPS, vehicle-use policies, pursuit records and maintenance files may exist.

Rideshare and delivery platforms may additionally possess:

  • login times;
  • ride acceptance;
  • pickup and drop-off records;
  • route data;
  • delivery records;
  • driver communications; and
  • commercial insurance information.
Guides 14, 15 and 16 address these specialized evidence and insurance systems in greater detail.

Serious or disputed crashes may require formal reconstruction

Crash reconstruction is the disciplined use of physical, electronic and testimonial evidence to determine how a collision occurred.

Depending on the case, analysis may include:

  • scene measurements;
  • photogrammetry;
  • vehicle crush;
  • EDR data;
  • video timing;
  • speed analysis;
  • perception-response issues;
  • braking distance;
  • vehicle dynamics;
  • signal timing;
  • visibility; and
  • pedestrian or bicycle movement.
Reconstruction should follow the evidence rather than begin with a desired conclusion. Assumptions must be identified and tested against the physical record.

Traffic-signal timing can decide an intersection case

In a disputed red-light or protected-turn collision, witness memory may be less reliable than objective timing records.

Investigate:

  • signal phase and timing plan;
  • yellow interval;
  • all-red interval;
  • protected turn phases;
  • vehicle-detection systems;
  • signal malfunction records;
  • nearby video; and
  • vehicle approach speed.
The collision report may identify the traffic control. It usually does not replace the underlying signal records needed for a disputed timing analysis.

A complete crash investigation also connects the collision to the injuries

Liability evidence explains how the vehicles collided. Medical evidence explains what the collision did to the person.

Preserve:

  • EMS observations;
  • emergency-department records;
  • initial complaints;
  • diagnostic imaging;
  • photographs of visible injury;
  • subsequent diagnoses;
  • treatment progression;
  • work restrictions;
  • functional limitations; and
  • prior relevant medical history where causation is disputed.
Crash severity and injury severity are related questions, not identical questions. Vehicle photographs alone do not medically determine whether a particular person was injured.

A police citation does not replace civil causation analysis

A citation, criminal charge or lack of citation can be relevant to the investigation, but civil liability is ultimately determined under the applicable evidence and civil law.

“No ticket” does not mean “no civil liability.” Police enforcement decisions and civil comparative-fault determinations serve different purposes and use different procedures.

Conversely, the existence of a citation does not by itself determine all issues of causation, comparative fault or damages.

Build one master evidence timeline

Time period Evidence to preserve
Before impact Driver route, speed, phone activity, app status, traffic controls, visibility and witness observations
Seconds before impact EDR, video, braking, steering, accelerator, signals and lane movement
Impact Contact points, crush, debris, video and electronic event data
Immediately after Final positions, statements, photographs, 911 calls, EMS and police observations
Hours / days after Medical records, surveillance requests, vehicle inspections and digital preservation
Later investigation Reconstruction, discovery, insurance records, expert analysis and testimony

Citizen workflow for investigating a Washington crash

Protect life and safety first. Call emergency services when appropriate and avoid creating further roadway danger.
Identify every person and vehicle. Drivers, owners, passengers, witnesses, employers and insurers can all matter.
Preserve the original scene if it can be done safely. Photograph positions, lanes, traffic controls, weather and transient evidence.
Move property-damage-only vehicles when Washington law requires it. Moving a vehicle to safety does not determine fault.
Obtain independent witness contacts. Do not assume police will identify everyone who saw the crash.
Determine whether a collision report is required. Washington's present property-damage threshold is $1,000, and injury or death independently triggers the reporting statute.
Obtain the police collision report and supplements. Then identify what underlying factual data and signed witness statements exist.
Search immediately for video. Look beyond the vehicles to businesses, homes, transit systems and government cameras.
Preserve both vehicles when mechanical condition, speed or impact dynamics are disputed. Avoid destructive repair or disposal before necessary inspection.
Identify onboard recording systems. Determine whether EDR, telematics, navigation or crash-notification data may exist.
Use Washington's lawful access rules for vehicle data. Owner consent, discovery or court process may be required.
Identify relevant phone and application evidence. Preserve the issue without assuming unrestricted access to private devices.
For commercial, rideshare or government vehicles, open the specialized evidence track. Dispatch, GPS, platform, fleet and agency records may be central.
Preserve medical evidence from the beginning. Liability and medical causation should develop in parallel.
Use reconstruction when the physical evidence justifies it. Serious injury, death, disputed signal timing, multiple vehicles or conflicting accounts can warrant expert analysis.
Separate facts from conclusions. Maintain the raw photographs, records, witness accounts and data even when later experts disagree about what those facts mean.

Primary authority behind this guide

RCW 46.52.020 — Duties after a collision

Requires stopping, exchange of specified identifying and insurance information, reasonable assistance to injured persons, and movement of vehicles following qualifying property-damage-only collisions. The statute expressly provides that moving a vehicle does not affect fault.

RCW 46.52.030 — Collision reports

Establishes Washington's reporting obligation for qualifying crashes, the four-day reporting period where applicable, officer-report provisions and required collision-report information.

WAC 446-85-010 — Property-damage reporting threshold

Establishes the current Washington collision-reporting threshold at $1,000 in apparent damage to any one person's property.

RCW 46.52.070 — Police officer's collision report

Requires investigating Washington law-enforcement officers to report collisions as fully as the facts in their possession permit and establishes additional reporting duties for specified serious collisions.

RCW 46.52.080 — Confidentiality and evidentiary treatment of reports

Protects required accident reports, authorizes specified identifying disclosures to interested persons and limits evidentiary use of the protected reports.

RCW 46.52.083 — Factual data and witness statements

Requires factual data submitted by officers and signed witness statements, other than protected driver reports, to be made available to statutorily interested parties upon request.

Chapter 46.35 RCW — Motor-vehicle recording devices

Governs Washington vehicle-recording devices, manufacturer disclosures, confidentiality and access to recorded information.

RCW 46.35.030 — Access to recorded vehicle information

Generally restricts access by persons other than the owner while recognizing access through owner consent, discovery, court order and other limited statutory exceptions.

Evidence-preservation authority

Henderson v. Tyrrell
80 Wn. App. 592, 910 P.2d 522 (1996)

Important Washington spoliation authority addressing loss of physical evidence and directing attention to the importance of the missing evidence and the culpability surrounding its destruction or loss.

Cook v. Tarbert Logging, Inc.
190 Wn. App. 448, 360 P.3d 855 (2015)

Further develops Washington's spoliation analysis and explains that the importance of the evidence, the circumstances of its loss, control over the evidence and preservation obligations can affect available sanctions.

Bottom line

A Washington crash investigation should not begin and end with a police report. Start with safety, identification and the evidence that will disappear first. Preserve the scene, independent witnesses, photographs, video and the vehicles themselves. Obtain the official collision report, but also seek the underlying factual material and witness statements. Identify electronic evidence early: modern vehicles, phones, commercial fleets, rideshare platforms and government systems can preserve objective timing and movement information, while Washington law specifically regulates access to vehicle-recording data. Finally, connect the crash evidence with the medical evidence. The strongest investigation preserves the original facts first and allows police, insurers, attorneys and reconstruction experts to test their conclusions against the same evidence.

← Guide 17: Comparative Fault Guide 19: Crash Damages & Property Loss →
Public legal education only. Collision-reporting duties, evidentiary rules, privacy rights, discovery procedures and preservation obligations depend on the particular facts. Serious-injury, fatality, commercial-vehicle, disputed-liability and suspected-defect crashes may require prompt professional investigation before vehicles, recordings or other transient evidence are altered or lost.