In Knappett v. King County Metro, a Washington appellate case, Knappett sued the bus company because he sustained injuries "after slipping while exiting the bus on a rainy day." According to the plaintiff, the "yellow nosing strips, located at the edges of the stairs of Metro buses, become dangerously slippery when wet."
In an ironic twist, the jurors deciding the case were provided King County Metro bus passes by the court so that they would not have to pay transportation costs associated with jury duty. Apparently, this was standard procedure at the courthouse for all jurors. Both sides were aware that the court provided jurors bus passes.
Following a verdict in favor of the plaintiff, a juror came forward and revealed that he "had tested the slipperiness of a yellow nosing strip while exiting a Metro bus on the last day of trial." Upon learning this information, "Metro moved for a new trial based on juror misconduct [among other things]. The trial court denied the motion." The appellate court upheld the trial court's decision finding that the actions of the jurors [two jurors actually tested the nosing strip but the appellate court focused primarily on the actions of one particular juror] was not misconduct nor did it affect the verdict.
As a general rule, jurors may rely on their life experiences when deciding a case. However, they may not rely on extrinsic evidence this includes conducting experiments to learn information not introduced into evidence. In this case, the trial judge found that stepping on the yellow nosing strip was not extrinsic evidence but rather part of a juror's "everyday experiences during the trial." The trial court further noted that "[e]verbody knew they [jurors]were going to have to step on those strips getting on and off the buses." The trial court also pointed out that "Metro possessed all the information necessary to conclude that jurors might encounter the yellow nosing strips as part of their everyday experience during the trial...and jurors would naturally bring this knowledge with them into deliberations."
The trial court concluded by finding that because the juror's "observations were consistent with the uncontroverted evidence adduced at trial, it could not have prejudiced Metro's case."