9.3 Traffic Crash Investigations

Traffic Crash Investigations

Crash scenes are among the most common — and most hazardous — assignments a North Carolina patrol officer handles. The 24-hour traffic crash investigations block trains officers to protect life first, preserve evidence second, and produce an accurate report that can support civil, criminal, and traffic-charge outcomes. The same scene-management habits feed into broader Traffic Incident Management (TIMS) practices used by law enforcement, fire, EMS, and NCDOT partners.

Scene Safety Comes First

Before measuring a skid mark, stabilize the scene:

1. Position the patrol vehicle to shield the work area and warn approaching traffic; use lights strategically.
2. Check for injuries and request EMS without delay when anyone is hurt or reports pain.
3. Prevent secondary crashes — the leading killer at incident scenes — by creating a temporary traffic buffer, using flares/cones when available, and assigning an officer to upstream warning if staffing allows.
4. Identify hazards: leaking fuel, downed wires, airbag residual risk, battery fires (including EV/hybrid considerations), and hostile bystanders.
5. Account for all involved parties and vehicles, including those that left the scene (hit-and-run).

If the roadway cannot be made reasonably safe, request additional units, fire/rescue, and NCDOT / incident response resources rather than working exposed in a live lane.

Evidence: Skid Marks, Debris, and Vehicle Condition

Physical evidence tells the story when witnesses conflict. High-yield evidence categories include:

You are not expected to be an accident reconstructionist after one BLET block, but you are expected to recognize what must be photographed and preserved before wreckers destroy the scene.

Diagramming Concepts

A crash diagram translates a three-dimensional scene into a two-dimensional record. Cognitive standards:

• Orient the diagram with a north arrow and label the roadway (route number, intersecting street).
• Show lane lines, shoulders, traffic control devices, and fixed objects (poles, trees, guardrail) that matter to causation.
• Place vehicles at final rest and, when known, approximate positions at impact.
• Use standard symbols taught in your academy materials; keep the diagram neat enough that a supervisor, prosecutor, or insurance investigator can understand it without you present.
• Pair the diagram with a narrative that explains sequence: pre-impact motion → conflict → impact → post-impact movement → final rest.

Measurements (when taken) should reference fixed points, not movable debris. If conditions prevent a full measured diagram, say so in the report and rely on photographs — never invent precision you did not capture.

Hit-and-Run

Hit-and-run investigations combine crash work with criminal investigation. Immediate priorities:

• Broadcast vehicle description, direction of travel, damage location, and any partial plate.
• Preserve paint transfer, debris left by the fleeing vehicle, and CCTV / nearby business camera leads.
• Obtain medical attention for victims and identify witnesses before they leave.
• Treat statements, 911 calls, and digital leads as time-sensitive — delay destroys solvability.

Hit-and-run is not "just a traffic report." Document it with the seriousness of a crime scene while still managing roadway safety.

Report Thresholds and Documentation Themes

North Carolina agencies and Chapter 20 reporting rules distinguish crashes that require formal reports from minor non-reportable property exchanges (thresholds and forms are set by statute/policy and can be updated — learn the current agency/DMV reporting criteria taught in class). Cognitive themes that remain stable:

• Injury, death, or significant property damage generally push a crash into full investigative / reportable territory.
• Driver exchange of information may handle some minor property-damage-only events, but officers still respond when there is injury, roadway blockage, impairment suspicion, hit-and-run, or disputes.
• Reports must identify parties, insurance, contributing circumstances, and diagram/narrative support.
• Never omit an impaired-driving investigation merely because a crash also occurred — crashes are often the first indicator of a DWI.

Accuracy beats speed. A rushed, contradictory report harms prosecutions and civil fact-finding more than a delayed but correct one.

TIMS / Incident Management Awareness

Traffic Incident Management (TIM) — often discussed in NC training alongside TIMS-style multi-agency coordination — is the shared playbook for clearing incidents safely and restoring traffic flow. Patrol officers contribute by:

• Establishing upstream warning and protecting responders.
• Using the quick-clearance mindset when vehicles can be moved from travel lanes without destroying needed evidence.
• Coordinating with fire, EMS, towing, and NCDOT rather than working in silos.
• Communicating lane-blockage status so traffic operations partners can manage diversions.
• Recognizing that every unnecessary minute of lane closure raises secondary-crash risk.

TIM is not an excuse to skip evidence work on a serious or criminal crash; it is a reminder that safety + evidence + mobility are simultaneous goals. On minor property crashes, prompt lane clearance after essential documentation often is the public-safety decision.

Investigative Mindset for the Exam

When a scenario describes a crash, prioritize in this order: life safety → secondary-crash prevention → evidence preservation → diagram/report completeness → criminal follow-up (hit-and-run, DWI, reckless). That sequence is the operational heart of the 24-hour crash block.