The new legislature change is Virginia code § 46.2-1049 which states a person may not operate a vehicle on a highway unless the exhaust is in good working order and in constant operation to prevent excessive or unusual levels of noise. If the exhaust system is found in not good working order, this will be a primary offense.
Arlington County P.D. are helping the community understand the new legislature change through information education on their Twitter. They also opened the Ongoing Transportation Complaint Enforcement Request form to report an ongoing and recurring loud exhaust issue.