Cross-Examination of a Crash Reconstructionist


Crash reconstruction is a science that involves mathematics and physics to determine what happened before, during, and after a collision. Reconstruction witnesses testify about the details of a collision, such as the speed of a vehicle, the cause of a collision, and the motion of the vehicle before and after an impact.
David Serna, a lawyer of over 40 years, advises young prosecutors in preparing for the cross-examination of defense reconstruction witnesses. The prosecutor must know whether the evidence or data gathered and used by the witness supports a reliable conclusion.
Here are three things to remember before conducting a cross-examination of reconstruction witnesses.
1.       Review the crash report

It is important to read the crash report of the opponent’s expert crash reconstructionist. The prosecutor’s crash reconstructionist can help him understand the factors considered by the opponent’s reconstruction witness and determine the shortcomings and loopholes of the report.

Going over the crash report also helps the prosecutor see whether there are admissions given by the crash reconstructionist.

2.       Check if the witness is qualified

A crash reconstruction witness must be an expert in crash scene investigations and in the application of scientific formulas and methodologies. A mathematician may know different mathematical formulas but not have enough knowledge about crash scene investigations.

David Serna, a lawyer of invaluable experience, says it is important that the prosecutor knows the background of the expert witness. This helps in determining whether the witness is equipped with the knowledge, ability, and skill required of an expert.

3.       Check if the witness applied the proper formula

Under the Rules of Evidence, an opinion that gives a reasonable degree of scientific certainty is required of expert witnesses. It is crucial, therefore, that the expert used scientifically accepted principles in interpreting the data or evidence he gathered during his crash scene investigations.

The prosecutor must determine the lack of qualification of the witness so that he can file a timely pre-trial motion challenging the principles applied by the expert.

Follow David Serna, a lawyer based in New Mexico, for more tips on litigation, direct examination, and cross-examination.

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