Utah Code Ann. § 41-6a-1626
(1)
(2)
(b)
(ii) A diesel engine manufactured on or after January 1, 2008, may not emit visible contaminants during operation:
(iii) A diesel engine manufactured before January 1, 2008, may not emit visible contaminants of a shade or density that obscures a contrasting background by more than 20%, for more than five consecutive seconds:
(c) A person who violates the provisions of Subsection (2)(a) is guilty of an infraction and shall be fined:
(d) A person who violates the provisions of Subsection (2)(b) is guilty of an infraction and shall be fined:
(e)
(i) As used in this section:
(3)