Judicial notice is a rule in the law of evidence that allows a fact to be introduced into evidence if the truth of that fact is so notorious or well-known, or so authoritatively attested, that it cannot reasonably be doubted. This is done upon the request of the party seeking to rely on the fact at issue. Facts and materials admitted under judicial notice are accepted without being formally introduced by a witness or other rule of evidence, even if one party wishes to plead evidence to the contrary. Judicial notice is frequently used for the simplest, most obvious common sense facts, such as which day of the week corresponded to a particular calendar date or the approximate time at sunset. However, it could even be used within one jurisdiction to notice a law of another jurisdiction—such as one which provides average baselines for motor vehicle stopping distances. Judicial notice in the United States Judicial notice in the Federal Rules of Evidence In the United States, Article II of the Federal Rules of Evidence ("FRE") addresses judicial notice in federal courts, and this article is widely copied by U.S. States. Article II of the FRE consists of a single rule, Rule 201. FRE 201 covers judicial notice of adjudicative facts, which are those concerning the parties to a proceeding, but not of legislative facts, which are general. FRE 201(b) permits judges to take judicial notice of two categories of facts: Those that are "generally known within the territorial jurisdiction of the trial court" (e.g. locations of streets within the court's jurisdiction) or Those that are "capable of accurate and ready determination by resort to sources whose accuracy cannot reasonably be questioned" (e.g. the day of the week on a certain date). FRE 201(c) notes that judicial notice may be permissive or mandatory. Under the wording of the rule, judicial notice is permissive if the court takes such notice on its own but mandatory if a party requests it and the court is supplied with the necessary information. Courts have ruled that judicial notice must be taken of federal public laws and treaties, state public laws, and official regulations of both federal and local government agencies. A trial court's decision to take judicial notice or not to do so is reviewed on appeal under the standard of abuse of discretion. Judicial notice and the burden of proof FRE 201(f) establishes that