Accident Reconstruction

Traffic Accident Reconstruction

ACTARTraffic accident reconstruction is the effort to determine, from whatever resources are available, how an accident happened. A traffic accident reconstructionist must be familiar with the application of a wide range of mathematics and specialized aspects of vehicle technology.

Because of the wide range of knowledge required by the accident reconstructionist, voluntary certification is available through the Accreditation Commission for Traffic Accident Reconstruction. ACTAR certification includes education, work experience, and successful completion of a comprehensive examination.

Accident reconstruction deals with:

  • kinetic energy
  • conservation of momentum
  • seatbelttime-distance calculations
  • physical evidence from road and vehicle
  • crash scene photography analysis
  • lamp analysis
  • skid analysis 
  • airborne analysis
  • vehicle data and research
  • damage assessment
  • vehicle damage location, qualification and quantification
  • approach, impact and departure angles
  • approach speed calculation,
  • impact calculations and Delta-V calculation
  • post impact speed calculation

Dr. McElroy specializes in motor vehicle technology and accident reconstruction. This typically entails physical inspection of the damaged vehicles, examination of the accident scene, and reconstruction of collision events using engineering calculations based primarily on momentum, energy, and restitution equations.

Vehicles may include passenger cars, light trucks, commercial vehicles, bicycles, and motorcycles. Information on pre-crash, crash, and post-crash (the 3 phases of a crash) is compiled to best determine how the event (accident, collision, failure) happened. Issues investigated include:

  • Vehicle Speeds
  • Impact Severity
  • Driver Actions
  • Seat Belt Use
  • Accident Causal Factors
  • Collision Avoidance
  • Line of Sight / Visibility Problems
  • Mechanical Defects
  • Tire Failure
  • Black Box Data
  • Lamp Analysis

Collision Diagram

Motorcycle going wrong way on divided suburban street.
Motorcycle going wrong way on divided suburban street.