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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7 Responses

  1. naomi toh says:

    officer i wish you petrol my area. i live next to a main street but have duel-panned new windows, which can block all the noise from the street from cars , trucks and buses. But the loud Harley are the ones that the windows can't even block (the noise). In summer days they go back about 30 times a day, they woke my new born up about 10 times a day. And you know how bad it could be if a baby is scared and wakened. i'm really really tired of those loud harley. Do you think my local PD (Lakewood) can help?

  2. Andy Ford says:

    The city of Denver enacted a motorcycle noise ordinance that's based on the EPA matching label system about 2 1/2 years ago. It's worked very well to reduce the numbers of loud motorcycles. The city of Green Bay, Wis., also enacted an EPA label based ordinance and that has also work well.

    Since 1983, all new motorcycles are required to have an EPA noise compliance label attached to the chassis and a matching label stamped into the muffler. It's a violation of federal law to replace the certified exhaust system with one that isn't certified or to modify the legal muffler to produce more noise.

    The law is designed so that states and cities can adopt and easily enforce the law.

    California should adopt the EPA label system not only to reduce motorcycle noise blight but also to reduce air pollution.

    Although it's illegal under federal law to remove the air pollution equipment this is done routinely by bikers who install open pipes such as drag pipes.

    There is more information on this at the Noiseoff website.

  3. Patrish Crow says:

    I'll take Harley noise over neighborhood leaf-blowers anytime.

    • naomi toh says:

      don't just point to other when people accuse you making the noise. Two wrongs don't make a right. Lawnmowers, left-blowers are operated with a purpose, and nothing can replace them. but Harley guys could ride quietly, but they choose to make the obsessive noise to disturb others. TWO DIFFERENCE THINGS!

      don't even bring out the 'safety' reason. All the harley guys who wake the baby up wear black jacket, black helmet, if they really want to be safe, why not wear reflective orange jackets as DMV recommends. And spend the money on a safety course, not the straight pipe.

    • naomi toh says:

      leaf-blowers are used 3 times a year.

      loud bikes come by everyday.

      leaf-blowers are not loud at all, compare to loud motorcycles.

      of course I'm not talking about the normal loud, i'm talking about those choppers with extremely loud pipes.

      bikes come out from Harley factory are pretty quiet.

  4. Tom says:

    I live along a busy street in Phoenix. This is way too common! I hear these bikes at all hours of the night, even more so than booming stereos in cars. To me, this is just further proof of the ghetto culture taking over this country, or maybe it's just "look at me."

    The bikes are much louder than leaf blowers, semis, city buses. I'm paying too much in property taxes for this kind of volume at 3am on a Monday night.

  5. LanceThruster says:

    The exhaust noise legal limit is set too high. Too many vehicles seem at the max. Makes my one-time quiet neighborhood sound like a construction site. CA was going to pass a bill in 2003(?) that said exhaust modifications could not be louder than factory stock but that wording was changed to "not louder than legal limit" which means the noise will contiinue.

    I had the sheriffs explain to me that they cannot "have their 'peace' disturbed" but there has got to be way to file a class action style complaint so that people can add their names to patrol a particular stretch of road or highway to ticket thoose broadcasting the boom too far. I think merchants are losing business because boomers circle their lots just working to annoy There are local restaurants I won't go to anymore because their front glass window picks up all the street noise at the intersection.

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