California Civil Jury Instructions (CACI)

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 is reasonable.

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.”

Secondary Sources

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 Bender)

16 California Points and Authorities, Ch. 165, Negligence, § 165.31 (Matthew Bender)