28-955.04. Exhaust system; visual inspection; requirements; civil penalty A. A commercial motor vehicle that operates in this state shall have an exhaust system that is detectable by a visual inspection and that meets all of the following: 1. Is free from a defect that adversely affects sound reduction. 2. Is equipped with either a muffler or other noise dissipative device. 3. Is not equipped with a cutout, bypass or similar device. B. A person who violates this section is subject to a civil penalty of at least five hundred dollars. If the person shows the court that a muffler has been installed or the existing muffler has been serviced to comply with subsection A, the court may reduce or waive the civil penalty.
Arizona Legal Code