When should Utah courts abandon jury instructions about accident occurrence? Green v. Louder Explained

In Green v. Louder, the Utah Supreme Court addressed multiple trial court errors in a negligence case arising from a head-on collision, providing important guidance on jury instructions and expert testimony standards.

Background and Facts

Lora Green was a passenger in a vehicle driven by her mother, Marlene Murray, when Murray mistakenly drove into the wrong lane on a two-lane highway. Murray attempted to return to her lane when she saw Lloyd Louder’s approaching vehicle, but Louder simultaneously swerved into Murray’s lane to avoid collision. The vehicles collided head-on, causing Green significant injuries including a compound wrist fracture and degloving injuries. Green settled with Murray but proceeded to trial against Louder. The jury found Louder not negligent, and the trial court denied Green’s motion for a new trial.

Key Legal Issues

Green raised multiple claims of trial court error, including: (1) an improper jury instruction stating that the mere occurrence of an accident does not create a presumption of negligence; (2) exclusion of expert testimony regarding computer accident reconstruction analysis; (3) improper bolstering of defendant’s expert testimony; and (4) denial of discovery motions regarding insurance company communications.

Court’s Analysis and Holding

The court found two errors but deemed them harmless. First, it ruled that jury instruction 35, which stated that the mere fact an accident occurred does not support a conclusion of negligence, was erroneous and similar to the disapproved “unavoidable accident” instruction in Randle v. Allen. The court explicitly directed trial courts to “abandon the use of this instruction hereafter.” Second, the court found error in excluding the plaintiff’s expert testimony about Winslam computer software analysis, ruling that computer programs performing mathematical calculations do not involve novel scientific principles requiring heightened scrutiny under State v. Rimmasch. However, both errors were deemed harmless given the substantial evidence supporting the jury’s verdict.

Practice Implications

This decision provides crucial guidance for Utah practitioners. The court’s directive to abandon instructions about accident occurrence not creating presumptions of negligence eliminates a common jury instruction. For expert testimony, the decision clarifies that standard computer software used by experts in their field does not require novel scientific technique analysis but rather the ordinary reliability standard from State v. Clayton. The decision also reinforces that even multiple trial errors may not warrant reversal if substantial evidence supports the verdict and individual errors are harmless.