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Motorcycle Noise

Citizens Count Editor

New Hampshire law limits the volume of motorcycle exhaust noise at different levels, depending on speed and engine type.

  • 92 decibels when operating at idle speed
  • 100 decibels for 3 or 4 cylinder motorcycles when operating at 5,000 rpm or 75% of maximum engine speed
  • 96 decibels for all other motorcycles when operating at 2,000 rpm or 75% of maximum engine speed

State law is specific about how and where motorcycle noise should be measured: by a meter held at a 45-degree angle approximately 20 inches from the motorcycle’s exhaust pipe, in an open test area free of buildings, parked vehicles, signs or other sound-reflecting objects.

Fines for violations range from $100 to $300. There’s no exception for antique motorcycles.

Enforcement challenges

Law enforcement officials both in New Hampshire and in other states have made statements regarding the challenges of enforcing motorcycle noise rules. Complaints include:

  • Sound is notoriously subjective, making it difficult for an officer to know if a passing motorcycle is in violation or not.
  • Decibel meters can be expensive, and must be properly maintained and calibrated. Officers must be trained in their proper use.
  • It can be difficult to find an appropriate test environment when challenging potential offenders in the field.
  • The uncertainty of measuring sound can lead many violations to be tossed out in court.

History of NH  motorcycle noise laws

New Hampshire’s limits on motorcycle noise were first enacted in 2012, when the Legislature passed HB 1442.

Federal rules

The federal Environmental Protection Agency (EPA) has rules regarding motorcycle noise. Motorcycles in the United States must be made and sold with exhaust systems that do not exceed 80 decibels in volume. EPA-compliant exhaust systems are required to display a stamp or label when they leave the factory or showroom.

The EPA does make an exception to this rule for custom motorcycles built from kits. A rider is limited to unlimited use of one “kit bike” in his or her lifetime.

The EPA rules aren’t enforced on motorcycle drivers: only on dealers and manufacturers, and insiders say the EPA lacks the resources to routinely check for compliance.

For police to ticket motorcyclists for breaking noise rules, a state or local ordinance must be in place.

Motorcycles that exceed the 80 dB limit have often been modified by their owners. They might install a louder after-market exhaust system designed for racing bikes (as opposed to street bikes). Other owners modify their exhausts to break the 80 dB limit. Modifying an exhaust is also a violation of EPA rules, but is rarely enforced unless also prohibited by state law.

Town ordinances    

Towns in New Hampshire do not have the power to set their own motorcycle noise rules.

This was put to the test in 2010, when North Hampton passed an ordinance capping motorcycle noise at 80 dB. The ordinance was challenged, with a Rockingham County Superior Court judge ruling that the town did not have the power to set stricter standards for motorcycle noise than those set out in state law. 

Possible changes to NH motorcycle noise laws

Other states, cities and towns have implemented different policies for measuring, monitoring and enforcing motorcycle noise limits. Each method has its own challenges.

  • Require all motorcycles to have an exhaust with an EPA stamp. Nearly all motorcycles are supposed to have an EPA-stamped exhaust already when they leave the showroom or factory, and the absence of the stamp can indicate that a motorcycle has an illegal or modified exhaust. However, manufacturers don’t always make the stamps easily visible—they might face the wrong way, or be hidden by other parts of the vehicle, making them inaccessible to law enforcement officials.  
  • Set a curfew on motorcycle use. Supporters argue this keeps motorcycle noise from disturbing most citizens’ rest, but opponents argue it unfairly restricts the freedom of law-abiding motorcyclists.
  • Use other rules and standards for measurement, such as considering a motorcycle in violation if it can be heard from a predetermined distance (e.g. 200 feet). 
Citizens Count Editor

“NH should loosen restrictions on motorcycle noise.”

  • Motorcycles can be difficult for car and truck drivers to see, particularly if a driver is distracted. Loud exhaust noise is an important tool bikers can use to make sure others on the road are aware of their presence, which can help prevent accidents.
  • The motorcycle community should be invited to self-regulate noise or work with municipal and neighborhood leaders to come to an equitable solution rather than the state imposing rules from above.
  • There is no unproblematic way of measuring motorcycle noise to determine violations, making such cases uncertain in court.
  • Law enforcement officials have higher priorities than regulating excessive noise.
Citizens Count Editor

“New Hampshire should do more to regulate excessive motorcycle noise.”

  • There is no hard data to back the claim that loud pipes make motorcycle use safer. Motorcyclists can use their horns to alert drivers to their presence, and motorcycle exhaust noise is directed backward, where most threats to riders come from the front or side
  • Excessive exhaust noise constitutes a public nuisance, particularly during hours when people are sleeping. Reducing such noise could help prevent citizens from pushing for harsher restrictions on motorcycle use that potentially hurt all motorcyclists.
  • Loud noises can lead to blood pressure spikes, elevated heart rate, and other physical effects that make them a potential health hazard. 
  • Loud exhaust noise can make it more difficult for a motorcycle rider to hear sirens or other approaching vehicles.
  • According the American Hearing Research Foundation, prolonged, regular exposure to noise over 85 decibels can cause permanent hearing damage. That means having “loud pipes” might come at the cost of hearing impairment for motorcyclists and others similarly exposed.  


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