I use the term “computer-assisted” as a reminder that the computer, like the slide rule or hand calculator, is simply a tool that assists in the solution of complex mathematical models.
Computer reconstruction software programs do not interpret physical evidence, determine what physics principles are applicable, or decide what input data are appropriate. These programs do not eliminate the necessity to use the computer between our ears.
While the use of computer programs in accident reconstruction has not been a total success due to their frequent misuse, there are important and compelling advantages to computer-assisted analyses, including, but not limited to, the following:
- Programs can convert measurements, surveying output and digital photos to accurate, reliable and useful vehicle and scene data for the analyst.
- Computations are accurate, reliable, and really fast.
- Inputting a reasonable range of estimated values for stiffness coefficients, effective drag factors, approach and departure directions, and other important variables can yield reliable speed range estimates.
- Kinetic energy losses due to a complex damage profile can be easily computed and stored as a Fixed Barrier Equivalent (FBE) speed.
- Analyses may be computed using different methods to detect gross errors.
There are, however, some serious existing and potential pitfalls in the use of computer programs for accident reconstruction, including the following:
- Programs with a clear and orderly presentation tend to give the user unwarranted confidence in the results
- Comprehensive programs require more input data with the corresponding increased chance for error.
- Some sophisticated software may not provide intermediate results that can raise warning flags regarding assumptions and estimated input data.
- Individuals without adequate educational background and/or sufficient supervised practical experience often attempt to use computer programs to compensate for their lack of qualifications. This usually results in reconstructions with little or no relation to reality.
Good practice indicates that you never use a computer program unless you fully understand the underlying physics principles, can perform the mathematical computations used, are cognizant of the various assumptions involved, and, therefore, understand the proper use and limitations of the analysis.
More information on this and related topics can be found in Highway Accidents: Investigation, Reconstruction and Causation available at: Amazon.com. Information about the book and author is available at: www.bmorrow.com.