Insurance companies and lawyers must have accurate accident reconstructions to determine liability. Even a correct police report containing weather and road conditions or traffic light malfunctions does not include all the variable physical evidence at an accident scene.

For instance, during accident analysis, a police report may not accurately assess critical elements of speed, skid marks, conservation of energy and momentum, points of impact, crush damage, gouges, reaction distances, line-of-sight, driver actions, and mechanical, electrical, and electronic system failures, such as analysis of ABS brakes, airbags, alleged brake and steering failures, tire failures, and light bulb analyses to determine if headlights, brake lights, hazard, or turn signal lights were operative. Nor can a police report correlate the biomechanical aspects (see Biomechanical Engineering) of bodily injury with the accident facts.

Accident Reconstructionists trained in the proper methodology for data gathering, site measurements, and photography are essential to a thorough investigation, analysis, reconstruction, and successful resolution of any liability claim. The expert testimony as an expert witness can make all the difference in the courtroom.

The professionally licensed engineers are uniquely qualified to apply conservation of energy and momentum and other physics principles to provide thorough scientific data.

Analytical capabilities are enhanced by staged vehicle impact testing using state-of-the-art DAQ (Data Acquisition) and Accelerometer Systems that facilitate occupant impact testing, response documentation, and acceleration profiles, in addition to range of motion and injury potential assessments for:

• Complete Accident Investigation (passenger and commercial vehicles, motorcycles, bicycles and pedestrians)
• Vehicle Fire Investigation
• Accident Sequence Reconstruction
• Speed, Time and Distance Calculations
• Low-speed Impact Analysis
• Crush Damage Determination
• Braking, Steering and Mechanical Analysis, including Tires
• Electrical System and Electronic Component Failures
• Mechanical and Fuel System Failures
• Airbag and Seatbelt Fatalities/Injuries
• Damage Consistency Analysis
• Bodily Injury Analysis
• Occupant Response and Biomechanical Analysis
• Staged Vehicle Impact and Occupant Testing
• 3-D Accident Reconstruction Animation
• Biomechanical and Anatomical Diagrams
• Accident Diagrams
• Pretrial and Courtroom Presentations
• Expert testimony / Expert witness
• Accident Analysis
• Accident Reconstruction
• Auto Accident Reconstruction

In vehicle accident reconstruction, the speed of the vehicle is often of primary importance. Speed becomes a factor because of it’s:

• Legal significance relative to the posted speed limit,
• Physical role in the damage to the vehicles and the injuries to the occupants,
• Effects on the movement and maneuvering of the vehicles,
• Effect on a driver's visibility, perception and response to the developing accident.

There are a variety of ways a Reconstructionists can evaluate a vehicle's speed. Different mathematical formulas are used in these methods. While these may at first appear intimidating, the actual math is usually basic algebra and geometry. The formulas can be found in any of references 1-4 and information on data collection in references 5 and 6. The greater difficulty is to understanding the underlying physics and deciding exactly how the equations are applied to a particular situation. Hopefully, you can gain some insight into the logic of the physics and some understanding of the type of information which the Reconstructionist will need to perform an accident speed evaluation.

The evaluation of speed will usually be conducted with one or more of the following methods:

1. Momentum/Energy Analysis

2. Damage/Energy Analysis

3. Centrifugal Force Analysis

4. Launch, fall or Vault Analysis

5. Geometry and Timing Analysis

6. Event Data Recorders

Each of the methods will be outlined briefly along with some of the restrictions and limitations. The techniques which were discussed will cover most of the situations encountered in accident reconstruction. There are other analysis techniques which may be applicable and appropriate for a particular accident. All of these also have their advantages and limitations. The general objective is to provide the best evaluation represented by the data, verify the result with other methods if possible and consider the reasonable range of the results. With a general understanding of the analysis and its limitations, you should be able to determine whether this has occurred.