Collision Analysis

Our professional engineers and traffic accident reconstructionists analyze collisions in a very analytical and systematic approach. The following 10 steps briefly summarize the procedure for investigating and reconstructing an automobile accident:

1. Gathering Information

Initially, a forensic engineer or accident reconstructionist will gather all of the facts together such as police reports, photographs of vehicles and the accident scene taken by third parties, witness statements, 911 recordings, autopsy reports and other pertinent information.

2. Scene Investigation

The first step is to gather information right at the accident scene.

The scene of the accident is investigated in order to find evidence left at the roadway. Many times skid marks, yaw marks, fluid stains, vehicle debris, and gouge marks in pavement are left on the roadway and painted / flagged by police officers.

Measurements are taken at the scene so that an accident scene diagram can be prepared showing site specific conditions. This information is imperative in determining the point of impact and point of final rest of the vehicles, which can be used to draw conclusions on how the accident happened and calculate the speed of the vehicles.


Another significant part of the accident scene investigation is determining if the roadway contributed to the cause of the accident. The roadway is inspected for safety concerns such as a lack of traffic control devices and signage, lack of roadway maintenance, limited sight distance, lack of roadway maintenance, poor lighting, poor roadway design, poor stormwater drainage and other roadway defects.

3. Scene Mapping

The accident scene is measured / surveyed to provide a scaled drawing of the roadway evidence. This process is called scene mapping. Skid marks, yaw marks, fluid stains, vehicle debris, and gouge marks in pavement are often left on the roadway as a result of the accident.

These pieces of information are put together and used in reconstructing the car accident. Other information such as signage, traffic signals, and traffic control devices can also be shown on the drawing.

4. Vehicle Inspection & Analysis

Vehicles are inspected and analyzed to determine how vehicles collided, determine vehicle speeds, and check for defects that might have contributed to the accident.

Crush damage and paint transfer can be used to determine how the vehicles came in contact with one another. Furthermore, crush damage can be used to determine the amount of force applied to the vehicle and determine a change in velocity (delta-V).

5. Vehicle Black Box Downloads and Harvesting ECM Data

If there is a black box installed, forensic reconstruction can use this data.

Most non-commercial vehicles today have a black box which records information such as speed, throttle position, braking, seat belt usage, etc. during a crash event.

Whereas, commercial vehicles (i.e. tractor trailers) have an electronic control module (ECM) data which features much of the same data as a black box as well as diagnostic information for repairs and mechanical problems.

6. Review Witness Statements, Expert Testimony and Other Information

Witness statements and expert testimony can be used to assist the reconstructionist in determining how or why the accident happened. These documents are reviewed and taken into account when forming conclusions.

7. Calculations

In the process of reconstructing the accident, many physic and mathematical calculations are performed so that the engineer's opinions are scientifically supported.

The most typical calculations we perform deal with calculating the speed of the vehicles. There are hundreds of calculations that our engineers are familiar with such as force, speed from skid marks, speed from crush damage, delta-V, momentum, rollover analysis, work, energy, motion, time-distance relationships, critical speed yaws, airborne analysis, vaults, throw distance, braking efficiency, closing speed, speed from RPM, etc.

8. 3-D Accident Simulations

Many physic and mathematical calculations are performed using 3D technology.

3-D Accident Simulations are created using computer software programs that implement physics and mathematical calculations to simulate the car accident. A site specific roadway environment is used along with the correct make and model vehicles.

Preparing a simulation is an iterative process where multiple simulation trials are run in order to match the position of each vehicle with the corresponding evidence on the roadway such as the point of impact and point of rest.

The end result is a video that can show any angle of perspective such as from the driver's view point to an eye witness view point. Simulation videos have proven to be very useful in court because it provides an accurate account of how the accident happened to the judge and jury.


9. Engineering Reports

A written engineering report provides a detailed explanation of the purpose of the report, procedures, data collection, analysis and conclusions.

10. Expert Witness Services

Our engineers and accident reconstructionists provide expert witness services to attorneys to elaborate on technical issues for the benefit of the court. Our experts are very familiar with affidavits, Rule 26, depositions, court testimony, and preparing exhibits for presentation in court.

What Questions are Answered about How an Accident Happened?

A few of the aspects of crashes that our experts make determinations on are:

  • Vehicle Speed
  • Calculate Amount of Force Applied to Vehicle, Causing Bodily Injury
  • Determine if Headlights / Turn Signals were Turned On or Off at Impact
  • Angles of Impact
  • Determine seat belt usage
  • Determine if there is any Mechanical Failure in critical areas such as: Brake Systems, Tires, Air Bags, Seat Belts, and other safety equipment
  • Accident Scene Mapping, which shows how the accident happened using drawings, animations, or 3-D simulation videos

When you have a need for the investigation of an accident, call one of our professional engineers. Roadway evidence begins to disappear soon after the accident making it critically important to gather information as soon as possible. 



Have a question? Here's How To Contact Atlanta Engineering Services



Further Reading about Traffic Accident Reconstruction

Types of traffic accidents

Collision analysis in 10 steps

The accident scene investigation 

Atlanta Engineering Services, Inc. offers scene mapping... read more here

Learn how a vehicle black box and it's downloads can prove up evidence

View a sample engineering report here

Why you need an expert witness

Calculating the stopping distance

Multiple surfaces calculator to determine the stopping distance when there is more to consider.

Vehicle speed calculator

Accidents involving motorcycles

How a vehicle inspection analysis can help you after an accident

Reconstructing accidents involving Non-Commercial trucks

Read how vehicle defects can be the cause of a traffic accident here. 

It just may be those roadway ruts that caused you to hydroplane, find out more here

Was it poor design or layout that caused the accident?

See real 3D accident simulations with this link

More 3D accident reconstruction videos can be found here

See actual photos of traffic accidents here