Western States Law Library › Oregon › Guide 18
Crash Investigation
Fault should be the result of an investigation—not its starting assumption. A proper Oregon crash investigation protects people first, documents the scene, identifies every witness and vehicle, preserves physical and digital evidence, obtains the required reports and then reconstructs what occurred. The police report is important, but it is only one layer of the evidence.
Investigate first. Allocate fault later.
The central purpose of crash investigation is to preserve enough independent evidence to test what every driver, witness, police officer and insurer later says occurred.
Emergency care, scene safety and Oregon statutory duties.
People, vehicles, roadway, environment and witnesses.
Video, vehicles, digital records, EDR, GPS and documents.
Timeline, causation, technical analysis and comparative fault.
Safety and Oregon statutory duties come before evidence collection
Oregon requires drivers involved in collisions to stop, exchange information and perform additional duties depending upon whether property damage, injury or death resulted.
Stop, remain as required and exchange driver, owner, registration and insurance information.
Stop, remain, exchange information and render reasonable assistance to injured persons.
A qualifying crash witness must provide the witness's true name and address.
Oregon may require an operable vehicle to be moved
Oregon has separate driver and police collision-reporting systems
ORS 811.725 requires timely DMV reporting for a collision that meets ORS 811.720.
Current Oregon property-damage reporting threshold, subject to the statutory vehicle and towing rules.
ORS 810.460 generally requires the officer's report within 10 days after qualifying investigation or report preparation.
When should the Oregon DMV reporting question be triggered?
Current Oregon law and DMV guidance require reporting in specified injury, death, property-damage and towing circumstances.
A collision resulting in personal injury falls within Oregon's reporting framework.
Fatal collisions are reportable and require immediate emergency response.
Apply the specific rules in ORS 811.720 concerning vehicle damage, other property and towing.
The driver's DMV report is legally different from the police investigative file
Used for Oregon administrative and reporting purposes and given special evidentiary protection.
Can contain narrative, witnesses, diagrams, photographs, video, measurements and other records that must be analyzed separately.
Audit the police report rather than adopting it uncritically
Police documentation is often the first organized account of the crash, but it may not be a complete civil reconstruction.
Confirm spelling, addresses, vehicle ownership and passenger positions.
Verify roadway, lanes, directions of travel and impact location.
Identify what a witness actually reported versus the officer's later conclusion.
Preserve the scene in layers
| Evidence layer | What to document |
|---|---|
| Roadway | Lane configuration, width, shoulder, curves, grade, intersection, crosswalks, bicycle lanes and medians. |
| Traffic control | Signals, signs, pavement markings, construction control and temporary signage. |
| Physical evidence | Tire marks, gouges, debris, fluids, broken parts, curb or barrier contact and final vehicle positions. |
| Visibility | Sight lines, vegetation, parked vehicles, buildings, lighting and obstructions. |
| Environment | Weather, lighting, glare, moisture, ice, fog and road surface. |
| Fixed reference points | Intersections, poles, signs, lane lines and other stable reference points useful for later measurement. |
Photograph the entire vehicle—not only the damaged corner
Vehicle condition can preserve collision geometry, restraint evidence, mechanical issues and data sources that are invisible in one impact photograph.
Overall views, crush, paint transfer, lamps, tires, wheels, undercarriage and broken components.
Airbags, belts, seats, steering wheel, windshield, dashboard and loose objects.
Preserve VIN, model, trim, license plate and relevant equipment.
Search for video immediately
Passenger vehicles, commercial fleets, rideshare cars and government vehicles increasingly contain camera evidence.
Body camera, police dash camera and other public records can preserve crash or post-crash evidence.
Stores, fuel stations, homes, parking lots and doorbell cameras may contain relevant footage.
Oregon gives the vehicle owner important rights over EDR data
Some vehicles record pre-crash vehicle speed.
Inputs may help test whether avoidance action occurred.
Seat-belt and airbag-event information can be available depending on the vehicle.
Modern crash evidence extends far beyond the EDR
Travel history, location and fleet data may exist outside Oregon's statutory EDR definition.
Navigation, Bluetooth and paired-device evidence can be relevant in an appropriate case.
Preserve potentially relevant data lawfully where distraction or app activity is disputed.
Signal disputes require more than competing memories
A disputed green light is often a records-and-timing problem.
Determine the road authority responsible for the signal.
Signal phases, sequencing and programmed timing.
Intersection and nearby cameras can test signal-phase accounts.
Maintenance or complaint records can matter in an unusual case.
Build one synchronized crash timeline
Independent data sources become much more powerful when their clocks are compared.
Apparent factual conflicts can sometimes disappear—or become obvious— after time systems are normalized.
Some crashes require additional evidence systems
Qualification, dispatch, ELD, hours, maintenance, telematics and onboard video.
Login, acceptance, pickup, passenger status, drop-off and GPS.
Dispatch, CAD, body camera, dash camera, telemetry, assignment and maintenance.
Crosswalk, bicycle lane, sight line, lighting, signal and impact location deserve special attention.
Motorcycle, helmet, riding equipment, roadway marks and rider trajectory can all become relevant.
Identify impact sequence rather than treating a multi-vehicle event as one collision.
Police enforcement and civil fault are separate systems
Whether police issued a citation remains an investigative fact, but it should not replace examination of the scene, witnesses, vehicles and digital evidence.
Know when the case needs professional reconstruction
Stakes may justify preserving physical evidence before vehicles or roadway evidence disappear.
Technical analysis can test competing narratives against objective evidence.
Rollovers, pedestrian crashes, commercial vehicles and multiple impacts often require more than a routine scene diagram.
Preservation should identify evidence before it disappears
Serious crash files often involve records controlled by people or businesses that have no reason to keep them indefinitely unless they receive notice.
Vehicle, modules, tires, lamps, restraints and damaged components.
EDR, telematics, GPS, apps, cameras, logs and electronic communications.
Employer, government, TNC, business, property owner and fleet records.
Investigation is time sensitive
Safety, police, witnesses, photographs and identification of video sources.
DMV reporting, police records, surveillance, vehicle location and preservation notices.
Vehicle inspection, EDR, roadway data, institutional records and reconstruction decision.
Oregon 20-step crash investigation workflow
Call emergency services and address immediate hazards.
Stop, remain, exchange information and render required aid.
Apply ORS 811.717 without creating unnecessary danger.
Drivers, owners, passengers, witnesses and responding agencies.
Do this before independent witnesses leave the scene.
Scene, all vehicle sides, roadway, controls and physical evidence.
Vehicle, public, commercial and residential cameras.
Apply ORS 811.745 and 811.748.
Generally within 72 hours under Oregon's reporting statute.
Keep your own complete copy and proof of submission.
Report, diagram, photographs, recordings and supplemental material.
Prevent loss through repair, sale, auction or destruction.
Apply Oregon's owner-consent and court-order rules.
Telematics, GPS, applications, cameras and mobile-device data.
Signal timing, construction, maintenance and road-authority data.
Driver, employer, owner, business, public body and others.
Run Guide 03's full coverage investigation in parallel.
Compare every reliable time source.
Use technical expertise where the evidence or stakes justify it.
Apply Guide 17 to the preserved evidence—not an early assumption.
Primary Oregon sources for Guide 18
Driver duties, witnesses, roadway removal, DMV reports and police notification.
Read ORS Chapter 811 →ORS 810.460 governs qualifying police collision-report submissions to ODOT.
Read ORS 810.460 →Collision-report records, evidentiary restrictions and police-report retention provisions.
Read ORS Chapter 802 →Oregon ownership, consent, insurer access and exceptions governing motor-vehicle event-data recorders.
Read Oregon EDR Law →Current DMV instructions, $2,500 threshold, reporting methods and collision responsibilities.
Oregon DMV Collision Reporting →Oregon's statewide crash-data and crash-reporting program.
ODOT Crash Data →ODOT reporting instructions describing the police crash-report system and approved forms.
Review Police Crash Instructions →Combine the 2025 ORS with 2025 special-session and 2026 Oregon Laws for current-law research.
Check 2026 Update →Guide 19 turns the preserved evidence into Oregon economic, noneconomic and future-damages analysis.
Continue to Guide 19 →The crash report is a record of the investigation—not a substitute for one.
Protect people first. Identify every driver, passenger and witness. Photograph the scene and all vehicles. Preserve video before it is overwritten and vehicles before they are repaired or destroyed. File the required Oregon reports. Obtain the police file, vehicle data, roadway records, digital evidence and every relevant insurance policy. Build a synchronized timeline and use professional reconstruction when the facts or severity require it. Only after the evidence is assembled should anyone assign percentages of fault.