How Loud Is ‘Too Loud’?


After discussing motorcycles splitting traffic, several readers expressed a concern regarding loud exhaust systems.  As with most equipment violations, exhaust systems have specific limitations and requirements.

People hold different opinions about how loud is too loud, but the following is what the California Vehicle Code states: “No person shall modify the exhaust system of a motor vehicle in a manner which will amplify or increase the noise emitted by the motor with a manufacturer’s gross vehicle weight rating of less than 6,000 pounds, other than motorcycles, a sound level of 95 dbA (dbA is the decibel level).  Motorcycles manufactured before 1970, the noise limit of 92 dbA.  After 1969 and before 1973, 88 dbA.  After 1972, and before 1975, 86 dbA.  After 1974, and before 1986, 83 dbA.  After 1985, 80 dbA.”

According to the vehicle code, the newer the motorcycle the lower the decibel level. That may not, however, always be the case.  All motorcycles manufactured for sale in California meet the requirements when they arrive at the various dealerships.  There is a section that further states that it is unlawful for any person to sell or offer for sale a new motor vehicle that does not meet these requirements.  The issue usually starts when the purchaser immediately removes or modifies the factory equipment and replaces it with a system that does not comply with the lawful sound level.

There are many reasons why motorcycle owners change the exhaust system on their bikes.  Performance is generally given as the reason, but the specific loud rumble of the exhaust pipe tends to have something to do with it as well.  From the moment that we took a clothes pin and used it to hold a playing card against our bicycle spokes, we wanted that noise. Regardless of the reason the exhaust system was modified, if the decibel level is above the lawful limit, quite simply, it is unlawful.

What is a decibel? It’s a unit of measurement expressing how loud something is.  Zero is silent; 130 is reported to be at the average pain level.  Several years ago, I was a CHP training officer, and as part of our prescribed annual vehicle code training, I procured a decibel reading device and provided training to officers as to, in general, how loud is too loud.  There is no way that I can explain in the written word how loud, for example 90 decibels is, other that I am able to, as are most people, to know when a exhaust system has been modified to increase its decibel level. I have several friends that ride Harleys and the majority are all too loud.  I voice my concern that they are subject to a citation.  When does someone get a ticket for their vehicle being too loud?  As with most vehicle code violations, the officer uses his or her own discretion.  I can only speak for myself when it comes to the issuance of a citation.  If I hear a vehicle in my vicinity before I see it and or the sound causes vibration in my vehicle, I will make an enforcement stop.  If I stop a vehicle for an unrelated violation and it happens that the vehicle exhaust system is also too loud, I will issue a citation allowing the driver to correct the violation.

What about passenger vehicles with very loud, booming stereos?  The law states that if the sound can be heard from 50 or more feet from the vehicle, it’s too loud.

There are so many equipment violations, that if there is an interest in these, I would happily address them in a separate article.  The best rule of thumb is that before you decide to modify your vehicle, check with your local police department or CHP.  There are many aftermarket products whose small print indicates that this product may not be legal in California or for on highway use.  Safety and service is the CHP mission, and issuing citations for equipment violations is part of that mission.

Monty Hight is a retired California Highway Patrol officer and public information officer. He is the Northstate AVOID Campaign’s public information officer. He lives in Redding. More information on AVOID can be found here.

Monty Hight

Monty Hight is a retired California Highway Patrol officer and public information officer. He is the North State AVOID Campaign’s spokesman. He lives in Redding.

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