If a defendant is required by law to do something that they fail to do, they may be held liable under “negligence per se.”

Negligence per se only applies when a law is designed to protect a class of people from a certain type of injury, a defendant who violates that law is “negligent per se” and liable to all plaintiffs who are actually and proximately injured as a result.

Example: If a law requires all auto manufacturers to install seat-belts to protect vehicle owners, and you purchase a new car that does not come with seatbelts, the auto-manufacturer may be liable as negligence per se if you are injured.