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Accident Reconstruction

August 23, 2009 Consulting Areas No Comments
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.

Vehicle Technical Expert & Forensic Mechanic

August 23, 2009 Consulting Areas Comments Off on Vehicle Technical Expert & Forensic Mechanic
Vehicle Technical Expert & Forensic Mechanic
Box Truck Brake Failure

Box Truck Brake Failure

ASE Certified Master Technician and Expert Witness — Forensic Mechanic and Forensic Mechanical services:

  • mechanical and technical inspections
  • highway, off-road, and industrial vehicles
  • vehicle failure analysis and product liability
  • engines, transmission and drive train
  • electrical and electronic components
  • unintended acceleration or pedal misapplication
  • steering gear and linkage
  • suspension systems and failure analysis
  • brake system operation and failure analysis
  • air brakes, hydraulic brakes, & air-hydraulic
  • vehicle maintenance
  • fleet management

Manufacturing Defect results in Battery Explosion

flat car










Dr. McElroy has qualified in Federal and State Courts for criminal and civil trials.

  • Big TruckInsurance, Trucking and Vehicle Rental Industries
  • Individual Plaintiff and Defense Counsel
  • Industrial and Commercial Corporations
  • Local and National Municipalities
  • Other Governmental Entities

Dr. McElroy’s ASE Insignia Patch:

  • Master Automobile Technician
  • Master Heavy Truck Technician
  • Master Body & Paint Technician











Takata Recall Affects 46 Million Vehicles in U.S.

Takata Recall Affects 46 Million Vehicles in U.S.

Takata's airbag recall affects over 46 million U.S. vehicles. As of June 2017 65% HAVE NOT been replaced. (Reuters)

If unable to promptly get a replacement and worried about what could happen in a crash, then you can request from NHTSA to install an airbag On-Off Switch. Here is the NHTSA link: http://www.safercar.gov/Vehicle+Shoppers/Air+Bags/ON-OFF+Switch+Requests

Airbag Recall Technology

Airbag Recall Technology

When the inflator assembly is activated, sodium azide produces nitrogen gas which flows through the filter screen and into the airbag. Time between crash detection and complete airbag deployment is approximately 0.05 seconds. Typical airbag deployment speed is 200 mph. If the inflator assembly is structurally defective the inflator assembly can explode,

GM Ignition Switch Defect

GM Ignition Switch Turns OFF

A fundamental problem with the design of this ignition switch assembly in that the key can easily rotate to the ACCESSORY position which turns off the engine.

Turning off the engine affects vehicle controllability and turns off the airbag systems.

Photos From Website

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Millbrook GM European Proving Grounds

Millbrook GM European Proving Grounds

Dr. McElroy visits GM European proving grounds in 2011



Millbrook Overview

Millbrook Overview

Tomberlin Low Speed Vehicle

Tomberlin Low Speed Vehicle