Eliminate a defense to the vehicle noise statute

This bill amends Montana's vehicle noise statute by removing a defense that drivers could previously use to avoid conviction for excessive exhaust noise. Specifically, it eliminates the provision allowing a person charged with violating the noise limit to claim they had reasonable grounds to believe their vehicle was not in violation of the standard. The law requires that motor vehicles not emit exhaust noise exceeding 95 decibels as measured by a specific automotive engineering standard, except for motorcycles and quadricycles which are covered under a different regulation. This change directly affects vehicle owners and operators who may have been relying on the previous defense to contest noise violation charges.