Negligence per se means negligence in itself. In a tort case, a defendant who violates a statute or regulation without an excuse is automatically considered to have breached their duty of care and is therefore negligent as a matter of law. As a result, the only thing that must be proven at trial is whether the violation was the cause in fact and proximate cause of the plaintiff's injury. According to Restatement (Third) of Torts §14, an actor is negligent per se if they violate a statute that is designed to protect against the type of accident or harm caused by their conduct, and the plaintiff is someone the statute is designed to protect. Restatement (Third) of Torts §15 lays out exceptions where an actor’s violation of a statute is excused and not considered negligent. The exceptions include cases where the statute is unclear, the actor exercised reasonable care in attempting to comply with the statute, or the actor’s noncompliance with the statute resulted in less harm than if they complied. The most common application of negligence per se is traffic violations, where the driver is automatically considered negligent for violating the traffic code.
[Last updated in August of 2023 by the Wex Definitions Team]