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What is negligence per se in California?

California · updated 2026-09-01 · 530 words · 6 authorities cited

In California, negligence per se establishes a presumption of negligence when a person violates a statute, ordinance, or regulation that was designed to protect against the type of harm that occurred. This presumption can be rebutted if certain excusing conditions are met.

The rule

A party is presumed negligent if they violate a statute, regulation, or ordinance, and that violation is a substantial factor in bringing about the harm 4. If the violation is proven and was a substantial factor in causing harm, then the party is found negligent unless the violation was excused 4. If the violation is not proven, or if it was not a substantial factor, or if it was excused, then the question of negligence is decided based on other instructions 4.

How it applies

The doctrine of negligence per se creates a presumption of negligence, meaning that once a violation of a relevant law is established and shown to be a substantial factor in causing harm, the burden shifts to the violator to demonstrate an excuse 4. If a violation of a law has been established and is not in dispute, the jury must decide if the violation was excused 1. If it was not excused, the jury must then decide if the violation was a substantial factor in harming the plaintiff 1. If it was a substantial factor, the jury must find the violator negligent 1.

A violation of a law can be excused under several circumstances:

For example, if a minor violates a law, that violation may be excused if the minor was as careful as a reasonably careful child of the same age, intelligence, knowledge, and experience would have been in the same situation 2. If this condition is met, the minor is not considered negligent 2.

The concept of "substantial factor" is crucial in determining whether the violation led to the harm 4. A substantial factor is a factor that a reasonable person would consider to have contributed to the harm 5. It does not have to be the only cause of the harm 5.

What this does not cover

The provided sources do not define what constitutes a "statute, regulation, or ordinance" for the purpose of negligence per se [1, 4]. They also do not specify the types of "incapacity" that would excuse a violation 3. The sources do not elaborate on what "other reason excusing or justifying noncompliance" might entail 3. Furthermore, the sources do not provide a comprehensive definition of "negligence" outside the context of negligence per se, nor do they detail the general standard of care that applies when negligence per se is not established 6. The sources do not discuss the specific elements required to prove the initial violation of a statute, regulation, or ordinance [1, 4].

Authorities cited

1. CACI 419

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2. CACI 421

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3. CACI 420

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4. CACI 418

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5. CACI VF-401

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6. CACI 1221

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