While government regulation may currently be at the political forefront, Americans generally do not directly encounter federal regulations (with the exception of those who work in highly regulated fields). On the other hand, injuries caused by trucking accidents and defective medicines and medical devices impact many Americans. In these types of personal injury cases, which involve industries heavily regulated by the federal government (interstate trucking and medical products governed by the Federal Drug Administration (FDA)), the outcome for the plaintiff may turn on the effect and content of the relevant federal regulations.
Personal injury and tort law historically have been governed by state common law, i.e. the state laws made by judges based on precedent instead of statutes written by legislatures. As statutes began to regulate more behavior, statutes became more relevant in tort cases as indicators of negligence, e.g. breaking a traffic law may indicate negligence. Various ways to treat evidence that a party has broken some law have arisen. The most common two are (1) making the evidence is admissible as relevant to proving the party was negligent, and (2) proof that a relevant law was broken will constitute negligence per se, i.e. the judge will require the jury to find negligence. Although the courts dealt with the safety statutes as they came up, and to some extent accepted them as indicators of negligence, courts generally preferred to develop negligence law in negligence cases rather than allowing laws meant for some other purpose to determine the meaning of negligence.
On the opposite side of the issue, defendants occasionally tried to prove their absence of negligence by proving that they complied with the relevant state safety laws. Courts generally rejected these arguments, some deciding that they were irrelevant and inadmissible. They reasoned that state safety laws were a level of care below the appropriate standard of care in negligence cases, i.e., people ought not only obey the law, but ought to act in a reasonably safe way even in absence of statute requiring them to.
State courts could make these decisions with state statutes and state regulations because the state courts have the ultimate authority to interpret state statutes. Federal statutes and regulations on the other hand will trump state court decisions when Congress's intent to preempt state law is clear. Defendants began to argue that federal statutes and regulations preempted state court decisions on issues of standard of care, especially in highly regulated industries.
These arguments have had mixed results. Generally, the more highly and specifically an activity regulated for the purpose of maintaining its safety, the more likely courts are to find that the federal regulation will preempt state tort law. For example, it may be hard to that FDA regulations do not preempt a state court finding that a drug is unreasonably dangerous when the drug completed the FDA approval process. On the other hand, it will be easier to argue that FDA regulations requiring certain things to be on drug labels would not preempt a state from imposing a duty to issue more extensive warnings.
Federal statutes and regulations, however, do not always hurt the plaintiff's case. Where the defendant has failed to comply with a federal regulation that has a safety purpose and its failure to do so was part of the cause of the plaintiff's injury, proof of the failure to comply will often be enough to prove negligence. For example, trucking lines must keep records and carefully watch the amount of time their drivers spend on the road, to keep their drivers and the public safe. If the trucking line fails to keep proper records or allows a driver to drive an amount greater than that allowed by regulation, and that driver's truck injures someone, the trucking line's failure to follow the regulations will probably constitute negligence.