CACI No. 418 to 421: California's negligence per se presumption

When a safety statute sets the standard of conduct, a California plaintiff does not always have to argue about what a reasonable person would have done. Evidence Code section 669 presumes a failure to use due care when a person breaks a statute, ordinance or regulation of a public entity and certain conditions are met. CACI No. 418 is the instruction that puts that presumption in front of a jury (CACI No. 418).

What CACI No. 418 asks the jury

The judge first reads the law at issue. The jury then decides two facts: whether the party broke that law, and whether the violation was a substantial factor in the harm. If both are proved, the jury must find the party negligent, unless it also finds the violation was excused. If either fact is not proved, the jury still goes on to decide negligence under the ordinary instructions, so the case does not end there.

The instruction works in both directions. A defendant can use it to show a plaintiff broke a law, which feeds into comparative fault, and a plaintiff can use it against a defendant. The Directions for Use add a practical note: if the statute is long, the judge may read it at the end of the instruction.

The four conditions, and who decides each

Section 669 lists four conditions for the presumption (Evid. Code § 669):

1. The person violated a statute, ordinance or regulation of a public entity.
2. The violation proximately caused death or injury to a person or property.
3. The harm resulted from an occurrence of the kind the law was designed to prevent.
4. The injured person was in the class of people the law was meant to protect.

CACI No. 418 lists only the first two because those are the jury's. The cases quoted in the Sources and Authority explain that the first two are normally questions of fact, while the trial court decides the last two as a matter of law. So the judge decides whether the law defines the standard of care in this case before the jury ever hears the instruction. The party asking for the instruction carries the burden of showing all four conditions are met.

The sources also note which kinds of rules can qualify. California courts have held that federal laws and regulations can also supply the standard of care, and the California Supreme Court held in Elsner v. Uveges (2004) that Cal-OSHA provisions may be admitted like any other regulation. An administrative agency cannot create a duty of care on its own unless the Legislature delegated that power. One appellate court has said negligence per se has been applied to building code violations only in limited situations.

CACI No. 419: when the violation is not disputed

Sometimes a party admits breaking the law, or the evidence of the violation is undisputed. The Directions for Use for CACI No. 419 explain, relying on the Law Revision Commission comment to section 669, that the judge may then tell the jury the violation is established. The jury decides only causation and, where it applies, whether the violation was excused.

CACI No. 420: excuses that rebut the presumption

A violation can be excused if the party who broke the law proves one of these:

• An incapacity made the violation reasonable.
• The party used reasonable care and still could not obey the law.
• The party faced an emergency that the party's own misconduct did not cause.
• Obeying the law would have created a greater risk of harm to the party or others.
• Another reason the law recognizes excused or justified the noncompliance.

The Directions for Use say the burden shifts at this point to the party claiming the excuse. They also limit the second excuse: it should not be given unless the evidence shows an actual attempt to comply, and courts have said it belongs only in special cases. The test the California Supreme Court applied in Alarid v. Vanier (1958) asks whether the violator did what a person of ordinary prudence, wanting to obey the law, might reasonably be expected to do in similar circumstances.

CACI No. 421: minors

Section 669 treats children differently, and CACI No. 421 puts that rule to the jury. Under the instruction, a child who broke a law is not negligent if the child used the care that a careful child of similar age, intelligence, knowledge and experience would have used in the same circumstances. The statute itself speaks of a child's maturity, intelligence and capacity, and it withholds this rule when the child was engaged in an activity normally done only by adults and requiring adult qualifications. The Sources and Authority give driving as the example.

Questions to sort a negligence per se issue

• Which law was broken? Identify the statute, ordinance or regulation by number.
• What harm was it meant to prevent? The judge will ask whether this injury fits.
• Was the injured person in the protected group? The law's purpose answers this.
• Did the violation help cause the harm? The presumption does not prove causation.
• Is there an excuse? Emergencies, incapacity and greater-risk situations can rebut the presumption.

This page explains California's official jury instructions for general readers and is legal information, not legal advice. For a case going to trial, work from the official text and consult a lawyer licensed in California.