C.R.S. § 42-14-103
42-14-103. Uniform standard - local governments
42-14-103. Uniform standard - local governments. (1) A local authority may adopt or enact a resolution, ordinance, or other law concerning idling of a covered vehicle that is at least as stringent as, but not less stringent than, the state idling standard set forth in this article 14.
(2) The exemptions set forth in section 42-14-105 (2) apply to any local resolution, ordinance, or other law concerning the idling standard in section 42-14-105 (1).