A left turn, a defense verdict, and a missing instruction
Few things frustrate a plaintiff's trial lawyer more than a defense verdict in a case where the defendant plainly broke the Vehicle Code. That is close to what happened at trial in Drury v. Ryan, and in March 2025 the California Court of Appeal reversed it, holding that the jury should have been instructed on negligence per se (No. G063080, Mar. 21, 2025). The decision is a useful reminder that the instruction conference, not the liability facts, often decides the auto case.
The collision was the ordinary kind. The defendant attempted a left turn across three lanes of traffic to reach a parking lot and struck the plaintiff, who had the right-of-way. That maneuver implicated Vehicle Code section 21801, which requires a driver turning left to yield to oncoming traffic close enough to pose a hazard. Despite the statutory violation, the trial court declined to give a negligence per se instruction and charged the jury only on the general reasonable-person standard. The jury found the defendant not negligent, and the plaintiff appealed.
The holding
The Court of Appeal reversed. As appellate commentators including Horvitz and Levy noted in reporting the decision, the court held that where a statute explicitly spells out the standard of care for the situation, a negligence per se instruction is warranted so the jury understands how the statute bears on its analysis. Leaving the jury with only the generic reasonable-person charge, when a specific safety statute governed the exact maneuver at issue, was error, and on these facts it was prejudicial enough to require a new trial.
Negligence per se in California is not a separate cause of action. It is an evidentiary presumption, codified at Evidence Code section 669, that arises when a plaintiff shows the defendant violated a statute, the violation caused injury of the kind the statute was designed to prevent, and the plaintiff was in the class the statute protects. When those elements line up, the presumption shifts the burden, and the jury is told, through CACI No. 418, that it must find negligence unless the defendant proves a recognized excuse. Drury turned on the refusal to give that instruction at all.
Why the instruction matters more than it looks
The practical difference between the two charges is enormous. Under a bare reasonable-person instruction, the jury is free to decide that a driver who failed to yield was nonetheless acting reasonably, which is exactly what the Drury jury apparently concluded. Under a negligence per se instruction, the statutory violation does the work: once the jury finds the defendant turned left without yielding, negligence is presumed, and the defense must produce a recognized justification rather than a general appeal to reasonableness. That shift changes the center of gravity in closing argument and, often, the verdict.
The lesson for plaintiff practitioners is to treat the instruction conference as a place to win the case, not a formality after the evidence closes. Plead and prove the specific Vehicle Code section from the start. Build the record so the statutory elements are undisputed, request CACI No. 418 with the correct predicate statute identified, and object clearly if the court substitutes only the general negligence charge. A clean request and a clean objection are what preserved the issue in Drury and made reversal possible.
Choosing the right predicate statute
Not every traffic infraction supports the instruction, so the predicate has to be chosen with care. Section 669 requires that the statute define the standard of care with enough specificity to displace the general reasonableness inquiry. Right-of-way, speed, following-distance, and signaling statutes usually qualify because they prescribe conduct in concrete terms. Vaguer provisions, or the catch-all basic-speed law, invite a defense argument that the statute merely restates ordinary care and adds nothing. Pick the most specific applicable section, and be ready to explain why it spells out the standard rather than echoing it.
The excuse defense you should expect
Negligence per se is a presumption, not strict liability, and the defense can rebut it by showing the violation was excused, for example by an emergency not of the driver's making or by circumstances that made compliance impossible. Anticipate the excuse in your case-in-chief. If the defendant claims a sudden obstruction or a hazard forced the illegal turn, meet it with the physical evidence and the sequence of events before the defense frames the excuse for the jury. The presumption is a strong tool, but it is not self-executing.
Beyond the auto case
Drury reaches past the intersection. Any negligence case built on a specific safety statute, from a trucking regulation to a building-code provision in a premises claim, lives or dies on whether the jury is told the statute sets the standard. The reasoning applies directly to the right-of-way and equipment-violation issues we follow under auto accidents and to the federal motor-carrier rules that anchor so many truck and motorcycle cases. For plaintiff lawyers, the takeaway is narrow and worth repeating: identify the controlling safety statute early, request the negligence per se instruction, and preserve the objection, because the appellate record made in the instruction conference is the one that saved the plaintiff in Drury. We will keep following how the courts apply it in our case law and settlements coverage.