Although it is a criminal case, the recent opinion in State v. Farner, __ S.W.3d __, 2001 WL 1575024 (Tenn. 2001) has enormous significance to civil practitioners because of the opinion's discussion of computer-animated visualizations of automobile accidents. The case also clarifies the law on criminal causation.

On March 20, 1997, John Farner was driving his red Camaro and Landon Baker was driving his white Mitsubishi 3000 GT. This combination of high performance vehicles led to a drag race that ended when Baker's vehicle collided with oncoming traffic after Baker lost control of his vehicle. Baker and his passenger were killed. Farner was not physically involved in the collision but was indicted for instigating the drag race.

A police officer examined the scene as an expert in accident reconstruction. The officer gave a copy of his report to a professor at East Tennessee State University who created a computer-animated visualization "as a way of telling a story by creating a copy of reality with a computer." The professor explained that a computer-animated visualization differs from a computer simulation in that an animated visualization utilizes the testimony of an expert (the police officer) to recreate the event, and as such, is an illustration of the expert's testimony and opinion, while a simulation utilizes a computer to apply the laws of physics, and as such, purports to be an exact duplication of the event.

On appeal, the Supreme Court examined in detail the officer's testimony as an expert and in particular the basis of the officer's opinion regarding relevant scientific methods. With respect to the computer evidence, the court found that proof that explains a witness' testimony is usually referred to as an animation. In contrast, a simulation is based on scientific or physical principles and data entered into the computer, which is programmed to analyze the data and draw a conclusion.

The validity of the science must first be established before the simulation evidence is admitted. The court found that a computer animation offered to illustrate an expert's opinion will not be admissible unless the expert testimony is itself admissible. Further, the proponent must establish that the computer animation is a fair and accurate depiction of the event it purports to portray. Finally, because the jury may be so persuaded by its life-like nature that it becomes unable to visualize an opposing or differing version of the event, a computer-animated recreation must fairly and accurately portray the event.

Applying these rules the Supreme Court held that the trial judge abused his discretion in allowing the computer-animated visualization because it was not a fair and accurate portrayal of the events depicted and thus its probative value was substantially outweighed by the danger of unfair prejudice. The difficulty in the animation was that the police officer was unable to make a determination as to the speed of the defendant's vehicle but the computer animation included the defendant's vehicle and depicted its speeds throughout the animation. Moreover, portions of the visualization were inconsistent with the testimony of the witnesses.

Lastly, the Supreme Court found it particularly troubling that the animation was shown a total of 15 times at various speeds: "While we set no limit on how many times a visualization may depict an event, we emphasize that trial judges must carefully monitor such evidence and prevent cumulative presentation if it poses a substantial risk of unfairly prejudicing the defendant."

The defendant's conviction was also reversed because the judge failed to give appropriate instructions on proximate cause. The court adopted the view that the victim's contributory negligence does not relieve a defendant of criminal liability for his or her own criminally negligent conduct. However, a victim's contributory negligence may be considered in determining whether, under the circumstances, the defendant's conduct was a proximate cause of death, or whether the victim's conduct was an independent, intervening cause of the death. Rather than requiring trial judges to guess at what instructions might be appropriate in such cases, the Supreme Court thoughtfully provided specific jury instructions that are to be given in future cases regarding the critical issues of causation.

State v. Farner is an important decision that should be reviewed by both civil and criminal practitioners. This case is particularly important in light of the prevalence of companion civil litigation to criminal vehicular homicide prosecutions.

David L. Raybin is a partner with Hollins, Wagster and Yarbrough in Nashville where he concentrates in criminal trials and appeals. Raybin is the author of Tennessee Criminal Practice and Procedure (West 1984). He is also a member of the Tennessee Supreme Court Advisory Commission on Rules of Procedure. E-mail him at DRaybin@aol.com