Opinion ID: 2633411
Heading Depth: 2
Heading Rank: 3

Heading: exclusion of probert's testimony regarding computer analysis

Text: ¶ 24 Green argues the trial court erred by excluding Probert's expert testimony about the results of computations performed by an accident reconstruction computer program called Winslam. [5] The [q]ualification of a person as an expert witness... is in the discretion of the trial court. Patey v. Lainhart, 1999 UT 31, ¶ 15, 977 P.2d 1193. ¶ 25 At trial, Green's expert, Probert, testified that he generally used various analytical tools to assist him in reconstructing an accident, including computer programs. Regarding his use of Winslam he said, the last thing I do is evaluate that with various mathematical formulas through a computer program, or several, which I utilize in my business. When Probert was asked for an estimate of the impact speed of the vehicles, Louder objected, alleging that Probert based his opinion on the analysis performed by Winslam, but that he had failed to lay a proper foundation to establish the validity of the computer program under State v. Rimmasch, 775 P.2d 388 (Utah 1989). The court sustained the objection and allowed Green to question Probert on voir dire regarding his use of Winslam. ¶ 26 During voir dire, Probert testified he was unfamiliar with the principles and mathematical equations used by Winslam to estimate speed. However, Probert explained this was not problematic because he had reached his conclusions about speed independently from the use of Winslam in this case. In addition, he testified that his use of Winslam was limited to checking the accuracy of his findings, not for finding exact answers. In fact, Probert testified that computer programs are universally used by accident reconstructionists as a means to corroborate the accuracy of their findings. Ultimately, the trial court struck any testimony about Winslam's results. However, Probert was allowed to offer his independent opinion regarding impact speed. He testified that the impact speeds on these two vehicles, each, [were] between 15 and 20 miles per hour for both vehicles. ¶ 27 We agree with Green that exclusion of the results of Winslam's analysis was erroneous and that Louder's interpretation of Rimmasch is mistaken. In Rimmasch, we held that where expert testimony is based upon novel scientific principles or techniques, trial courts should apply the inherent reliability test. Rimmasch, 775 P.2d at 396-97 (citing Phillips v. Jackson, 615 P.2d 1228, 1234 (Utah 1980)). Although Louder claims Winslam is a magical black box, the use of computer software to perform complex mathematical calculations is certainly not based on novel scientific principles or techniques. [6] ¶ 28 Therefore, the appropriate standard for the admission of this testimony was set forth in State v. Clayton, 646 P.2d 723 (Utah 1982). In Clayton we explained that [o]nce the expert is qualified by the court, the witness may base his opinion on reports, writings or observations not in evidence which were made or compiled by others, so long as they are of a type reasonably relied upon by experts in that particular field. The opposing party may challenge the suitability or reliability of such materials on cross-examination, but such challenge goes to the weight to be given the testimony, not to its admissibility. Id. at 726 (emphasis added). The proper inquiry is whether accident reconstructionists reasonably and regularly rely on computer software programs, such as Winslam, to verify the accuracy of their findings. ¶ 29 Here the court heard evidence that computer programs are generally used in the field of accident reconstruction. Louder did not object or dispute this evidence; therefore, the Clayton standard was met. In addition, we have held that once an expert renders an opinion [he] must be allowed to explain the foundation for that opinion. State v. Kelley, 2000 UT 41, ¶ 18, 1 P.3d 546 (citing Patey v. Lainhart, 1999 UT 31, ¶ 33, 977 P.2d 1193). Although ultimately Probert was allowed to testify regarding speed, he was not allowed to fully explain the basis of his opinion. Therefore, the trial court erred by excluding the computer-confirmed testimony. However, we are not convinced that excluding this testimony affected the jury's verdict. Speed was apparently one factor in the causation of this collision, but by no means a determinative one. That being the case, we conclude the error was harmless.