Generally, a personal injury plaintiff must prove four elements to prevail in a negligence claim: duty, breach of duty, causation, and damages. However, in some cases, plaintiffs can take a “short cut” under the legal theory of “negligence per se.” Negligence per se is a Latin term that means negligence in and of itself. Under Washington D.C. law, negligence per se is applicable “where a particular statutory or regulatory standard is enacted to … prevent the type of accident that occurred.” Further, an “unexplained violation of that standard renders the defendant negligent as a matter of law.”
This means that the plaintiff must prove only that the statute was designed to protect against the type of harm caused in the accident, and that the defendant was the person or entity that engaged in the conduct. Therefore, when the facts of the case allow it, a plaintiff will almost always want to instruct the jury on negligence per se because it makes the plaintiff’s burden that much easier to meet.
For that reason, when a court erroneous instructs a jury on negligence per se, the defendant may have an issue on appeal because of the harm caused by the instruction. However, a recent D.C. Court of Appeals case held that an improper negligence per se instruction can be “redundant” rather than harmful in some cases, and does not always require reversal.