TRAFFIC ACCIDENT INVESTIGATION & RECONSTRUCTION

Traffic accident reconstruction is the process of gathering and analyzing available data pertaining to a specific traffic collision and determining the events which occurred immediately before, during, and after the collision. The traffic accident reconstruction is only limited by the amount of data, physical evidence and information which is available or provided.

Each traffic accident reconstruction is very unique. The reconstruction may take the form of a simple analysis as in determining if a headlight was incandescent at the time of impact, or may be as complex as recreating the actual collision using exemplar vehicles.

The traffic accident reconstruction generally requires the integration of a wide variety of complex automotive and mathematical disciplines to successfully reconstruct the events of the collision. The data used in reconstruction are derived from police reports, vehicle damage examination, accident scene investigation, photographs, examination of physical evidence, medical records, statements from witnesses and involved parties.

Once the formulation is completed, all possible factors pertaining to the collision are considered. The accident reconstruction process yields a collection of critical factors that must be evaluated to reach a valid conclusion. The final results are a set of conclusions and supportive data that will define the events of the collision, injury causation factors, accident avoidance potential, and the cause of the collision.

The traffic accident investigator is also required to determine the causation factors of the collision and determine comparative or associated factors. An analysis of cause may include who had the right-of-way at an intersection, establishing the length of time it would take a vehicle to accelerate from a stop sign to the point of collision, possible collision avoidance maneuvers or calculate a vehicle’s speed based on physical evidence.

THREE PHASES OF ACCIDENT INVESTIGATION & RECONSTRUCTION

Each traffic accident reconstruction is very unique and may require a variety of investigative skills and techniques. Prior to beginning a traffic accident investigation or reconstruction, consideration must be given to the extent and complexity of the available data. An individual who requests a traffic accident investigation and reconstruction should be aware of the available levels to meet their individual needs.

The three phases of an accident reconstruction may include any of the following functions:

A. VEHICLE INSPECTION

1. Damage and/or deformation analysis.
2. Determine the mechanisms of injuries.
3. Seatbelt system analysis.
4. Headlight examination.
5. Tire failure analysis.
6. Mechanical inspection.
7. Photograph and videotape vehicle.
8. Event Data Recorder (EDR) / Crash Data Retrieval (CDR) System Analysis

B. ON-SCENE INVESTIGATION AND COLLECTION OF DATA

1. Collision scene measurements.
2. Determine the coefficient of friction on the roadway.
3. Determine the superelevation of the roadway.
4. Determine the slope of the roadway.
5. Obtain traffic signal timing charts and scene diagrams.
6. Line of sight analysis.
7. Vision obstructions.
8. Vault or fall analysis.
      Take-off angle.
      Vertical distance traveled.
      Horizontal distance traveled.
9. Critical speed of the roadway.
      Radius of the roadway.
      Superelevation, positive or negative.
      Speed survey via radar.
10. Photograph and/or videotape scene.

C. RECONSTRUCTION OF DATA

1. Scale diagram of collision scene.
2. Scale diagram of vehicle deformation.
3. Scale diagram of interior specification.
      Illustration of occupant kinematics.
      Substantiate mechanism of injuries.
4. Speed analysis.
      Speed loss from skid marks.
      Speed loss based on deformation.
      Conservation of linear momentum.
5. Critical speed of roadway.
6. Speed of vehicle from centrifugal tire marks.
7. Speed of vehicle at time of vault, fall, or flip.
8. Time and distance analysis.
      A plot of each vehicle’s approach to the point of impact 1/10 th of seconds.
      Applicable collision avoidance techniques.
9. Recreation of the collision events using exemplar vehicles.
10. Results of headlamp examination.
11. Vehicle tests: stopping distances, reaction time, maneuverability, acceleration.
12. Results of seatbelt analysis.
13. Results of tire examination.
14. Results of vehicle inspection.
15. Diagram and results of occupant kinematic analysis.
16. Diagram and results of speed survey.
17. Computer generated printouts of all calculations.
18. Computer generated graphic displays.
19. Photographic displays.
20. Videotapes.