Negligence per se is a doctrine in US law whereby an act is considered negligent because it violates a statute (or regulation). The doctrine is effectively a form of strict liability.
Negligence per se means greater liability than contributory negligence.
In order to prove negligence per se, the plaintiff usually must show that:
The Common Law will not be abrogated by statute but may be adopted by statute. The Common Law will always remain our tradition and the basis of principles that inform the appropriate development of statutory laws and codes. New arrivals to the discussion may not like the word "owe" in the formulation of the discussion involving duties of care but it is understood that Tort law is about obligations and one party owes the other a duty of care in certain scenarios where we can say reasonably that such a duty exists and is rightfully owed, lets say, to a customer, to a passenger, to a business client and to a building occupant. We can say to the person who has failed his duty of care with poisoned products or negligent building works that he can face a claim where it will show that he will owe a duty of care, that he breached that duty of care and the claimant suffered harm or loss as a result of that breach. There is debate as to whether pure economic loss can be considered harm but it could be a significant loss and therefore sufficient harm in any context. We might have to reassess the discussion and ensure there is no doubt that economic loss is sufficient harm to satisfy a claim in tory and not only a claim under contract law or in Delict. The claimant can make his choice. The damages might be the same if awarded but it seems Tort is usually the body of law that we utilise to address duties, harm and loss when there is no evident written agreement between the parties.
In some jurisdictions, negligence per se creates merely a rebuttable presumption of negligence.
A typical example is one in which a contractor violates a building code when constructing a house. The house then collapses, injuring somebody. The violation of the building code establishes negligence per se and the contractor will be found liable, so long as the contractor's breach of the code was the cause (proximate cause and actual cause) of the injury.
A famous early case in negligence per se is Gorris v. Scott (1874), a Court of Exchequer case that established that the harm in question must be of the kind that the statute was intended to prevent. Gorris involved a shipment of sheep that was washed overboard but would not have been washed overboard had the shipowner complied with the regulations established pursuant to the Contagious Diseases (Animals) Act 1869, which required that livestock be transported in pens to segregate potentially-infected animal populations from uninfected ones. Chief Baron Fitzroy Kelly held that as the statute was intended to prevent the spread of disease, rather than the loss of livestock in transit, the plaintiff could not claim negligence per se.
A subsequent New York Court of Appeals case, Martin v. Herzog (1920), penned by Judge Benjamin N. Cardozo, first presented the notion that negligence per se could be absolute evidence of negligence in certain cases.
Negligence per se involves the concept of strict liability. Within the law of negligence there has been a move away from strict liability (as typified by Re Polemis) to a standard of reasonable care (as seen in Donoghue v Stevenson, The Wagon Mound (No. 1), and Hughes v Lord Advocate). This is true not just for breach of the common law, but also for breach of statutory duty. The criminal law case of Sweet v Parsley (which required mens rea to be read into a criminal statue) follows this trend. In this light, "negligence per se" may be criticised as running counter to the general tendency.