Utah Code § 10-8-47.5

(1) As used in this section, "knife" means a cutting instrument that includes a sharpened or pointed blade. (2) The authority to regulate a knife is reserved to the state except where the Legislature specifically delegates responsibility to a municipality. (3) (a) Unless specifically authorized by the Legislature or, subject to Subsection (3)(b), a municipal ordinance with a criminal penalty, a municipality may not enact or enforce an ordinance or a regulation pertaining to a knife. (b) A municipality may not enact an ordinance with a criminal penalty pertaining to a knife that is: (i) more restrictive than a state criminal penalty pertaining to a knife; or (ii) has a greater criminal penalty than a state penalty pertaining to a knife.