Exhaust System Inspection
The best way to follow up the stop is to have the vehicle's exhaust system and mufflers inspected, which greatly augments that enforcement approach and provides additional objective evidence; that evidence being the presence of an illegally tampered with exhaust system or improper mufflers which constitutes an equipment violation and is the root cause of the observed "excessive or unusual noise" emitted by the motorcycle. That inspection can either be perform by a properly trained police officer or by a properly-trained state authorized and supervised inspection mechanic. State laws should be revised to incorporate that enforcement approach.
Quill Driver Books of Fresno, California recently published Guide to Modified Exhausts: A Reference for Law Enforcement and Motor Vehicle Inspectors, written by Noise Free America: A Coalition to Promote Quiet. The information in the guide is intended to provide jurisdictions and law enforcement officers a means of dealing with the problem of excessively loud motorcycles that does not require the use of expensive sound measuring equipment or the necessity of conducting time consuming and cumbersome exhaust noise tests. It offers an alternative method to address the problem that is based on a simple, common sense approach based on exhaust system equipment standards.
Excessive motorcycle noise is a threat to public health and safety; it is also illegal. Law enforcement officers and motor vehicle inspectors should take action against excessive motorcycle noise.