Hernandez v. County of Los Angeles, 173 Cal. Rptr. 3d 226

Randy Hernandez dies after a Los Angeles County Sheriff’s car collides with his vehicle on the 110 freeway; Jocelyn Hernandez (minor) sues the County for negligence.
Evidence of Randy’s medical marijuana use was admitted to assess causation and Randy’s driving conduct.
County’s experts testified about marijuana impairment and postmortem interpretation; Jocelyn’s experts disputed impairment connection.
Jury verdict allocated 51% fault to Lauderdale, 35% to Lauderdale? (typo in original) and 14% to Randy; County liable for damages to Jocelyn.
Jocelyn moved for a new trial alleging juror misconduct and admission of marijuana evidence; trial court denied.
Opinion reverses and remands for new trial on the marijuana-evidence issue; County’s postjudgment appeal is moot after reversal.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Whether marijuana evidence was admissible to prove causation	Hernandez contends marijuana use was irrelevant absent causal link	County argues marijuana impairment is probative of causation	Evidence improperly admitted; not establishing causation; prejudicial error
Whether admission of marijuana evidence required reversal or could be cured	Such evidence biased jurors and affected liability apportionment	Any prejudice minimal; evidence supported by some expert testimony	Erroneous admission likely affected outcome; remand for new trial

People v. Eubanks, 53 Cal.4th 110 (Cal. 2011) (evidence must be probative and not unduly prejudicial in complex causation)
Ajaxo Inc. v. E*Trade Group Inc., 135 Cal.App.4th 21 (Cal. App. Dist. 2nd Dept. 2005) (abuse of discretion standard for evidentiary rulings; prejudice vs. probative value)
Brokopp v. Ford Motor Co., 71 Cal.App.3d 841 (Cal. App. 3d 1977) (prejudice from error requires showing of probable better outcome absent error)
Smith v. Workers’ Comp. Appeals Bd., 123 Cal.App.3d 763 (Cal. App. 3d 1981) (proximate cause burden to prove intoxication contributed to accident)