The Department of Public Health and Environment adopted 5 Colo. Code Regs. §1001.15, Reduction of Diesel Vehicle Emissions. The rule revise Regulation Number 12 to conform to provisions of House Bill 11-1157, which permits heavy-duty vehicles that are registered in the Fleet Self-Certification Opacity Inspection Program area, but are physically based and principally operated outside of the program area, to forgo the periodic opacity testing requirements contained in Air Quality Control Commission Regulation Number 12 Part A. The rule takes effect December 15, 2011. See http://www.sos.state.co.us/CCR/Upload/AGORequest/AdoptedRules02011-00485.DOC.