Utah Code Title 41. Motor Vehicles § 41-6a-304. Obeying devices--Effect of improper position, illegibility, or absence--Presumption of lawful placement and compliance with chapter

(1)(a) Except as otherwise directed by a peace officer or other authorized personnel under Section 41-6a-209 and except as provided under Section 41-6a-212 for authorized emergency vehicles, the operator of a vehicle shall obey the instructions of any traffic-control device placed or held in accordance with this chapter.

(b) A violation of Subsection (1)(a) is an infraction.

(2)(a) Any provision of this chapter, for which a traffic-control device is required, may not be enforced if at the time and place of the alleged violation the traffic-control device is not in proper position and sufficiently legible to be seen by an ordinarily observant person.

(b) The provisions of this chapter are effective independently of the placement of a traffic-control device unless the provision requires the placement of a traffic-control device prior to its enforcement.