413.Custom or Practice
You may consider customs or practices in the community in deciding
whether [name of plaintiff/defendant] acted reasonably. Customs and
practices do not necessarily determine what a reasonable person would
have done in [name of plaintiff/defendant]’s situation. They are only
factors for you to consider.
Following a custom or practice does not excuse conduct that is
unreasonable. You should consider whether the custom or practice itself
New September 2003
Directions for Use
An instruction stating that evidence of custom is not controlling on the issue of
standard of care should not be given in professional malpractice cases in which
expert testimony is used to set the standard of care. (See Osborn v. Irwin Memorial
Blood Bank (1992) 5 Cal.App.4th 234, 277 [7 Cal.Rptr.2d 101].) The instruction
may be used if the standard of care is within common knowledge. (See Leonard v.
Watsonville Community Hospital (1956) 47 Cal.2d 509, 519 [305 P.2d 36].)
This instruction is also inappropriate in cases involving strict liability (Titus v.
Bethlehem Steel Corp. (1979) 91 Cal.App.3d 372, 378 [154 Cal.Rptr. 122]) or cases
involving negligence in the use of public roads (Shuff v. Irwindale Trucking Co.
(1976) 62 Cal.App.3d 180, 187 [132 Cal.Rptr. 897]).
Sources and Authority
• Evidence of custom and practice is relevant, but not conclusive, on the issue of
the standard of care in cases of ordinary negligence. (Holt v. Department of
Food and Agriculture (1985) 171 Cal.App.3d 427, 435 [218 Cal.Rptr. 1].)
• Restatement Second of Torts, section 295A, provides: “In determining whether
conduct is negligent, the customs of the community, or of others under like
circumstances, are factors to be taken into account, but are not controlling
where a reasonable man would not follow them.”
6 Witkin, Summary of California Law (10th ed. 2005) Torts, §§ 897, 898
1 Levy et al., California Torts, Ch. 1, Negligence, § 1.30, Ch. 3, Proof of
Negligence, § 3.33 (Matthew Bender)
California Products Liability Actions, Ch. 2, Liability for Defective Products,
§§ 2.11, 2.21 (Matthew Bender)
33 California Forms of Pleading and Practice, Ch. 380, Negligence (Matthew