If we have ordinances regarding the noise emitted by mufflers, how are these vehicles passing safety inspections? Is this not part of the inspection?
Excellent question. Yes, there are numerous statutes and ordinances covering muffler noise on automobiles, mopeds, and motorcycles. Why are they passing safety inspections? Because State of Hawaii and City and County of Honolulu claim that it's too hard to enforce these laws. Specifically, most of the laws are written, according to the authorities, too broadly. For example, quoting in part:
Illegally Modified Mufflers And Exhausts.
Hawai'i Law - ROH Sec. 15-19.28 Mufflers--Noise-Controlling Devices.
(a) No person shall operate a motor vehicle on a public highway or street unless such motor vehicle is equipped, at all times, with a muffler or mufflers in constant operation and of such length and size or of sufficient capacity for the motor and/or exhaust system to prevent the escape of excessive or annoying fumes or smoke, and excessive or unusual noise. The term "excessive or unusual noise," as used in this section, means noise in excess of the usual noise which would necessarily result from the operation of a motor when reduced to the minimum by a muffler such as is defined herein...
Both HPD and the City Attorney maintain that "excessive" isn't clear. What's excessive to one person isn't excessive to another. Here's another example:
Hawai'i Law - HRS Section 291-22 Regulation Of Exhaust Pipe And Muffler.
It shall be unlawful for any person to drive upon the public highways any motor scooter, as defined in section 286-2, the exhaust pipe or muffler of which has been so changed from the factory design as to increase the volume or audibility of the explosions within the motor thereof. In this example they maintain that it's not possible to interpret "increase the volume" and, therefore, they can't enforce this law. Yet another:
Hawai'i Law - HRS Section 291-24 Motorcycles And Mopeds, Noisy Mufflers; Penalty.
(a) Every motorcycle and moped moving under its own power on a public highway shall at all times be equipped with a muffler in constant operation to prevent any excessive or unusual noise and no such muffler or exhaust system shall be equipped with a cutout, bypass, or similar device. No person shall modify the exhaust system of a motorcycle or a moped in a manner which will amplify or increase the noise emitted by the motor of such motorcycle or moped above that emitted by the muffler originally installed on the motorcycle or moped...
Here the sticking point with the authorities is "increase the noise emitted by the motor of such motorcycle or moped above that emitted by the muffler originally installed..." How do we know how loud the original was compared to the modification. they ask? And yes, there's one for automobiles also:
Hawai'i Law - HRS Section 291-24.5 Motor Vehicle Muffler.
(a) No person shall use on a public highway, sell, alter or install a muffler which will noticeably increase the noise emitted by a motor vehicle above that emitted by the vehicle as equipped from the factory...
Same arguments. But what will probably really raise your temperature is this. On the large motorcycles, the biggest offender of modified exhausts and the noise they generate, is that these modifications completely remove the "muffler" component leaving nothing but a straight pipe from manifold to atmosphere. They're intentionally designed to maximize the noise/resonance of the exhaust. So where an EPA approved motorcycle exhausts has a nominal noise level of approximately 81dB(a), these modified pipes can reach 125dB(a). Anything above 120dB(a) is considered a hazard to hearing.
But here's the temperature raising part. The Periodic Motor Vehicle Inspection (PMVI) for Motorcycles at page 5 says that if a motorcycle does not have a muffler it is to be failed for safety. Nonetheless, spend some time at any of the State's inspection stations and sooner of later (usually sooner) you'll see a motorcycle with straight pipes, clearly no muffler, being passed in safety inspection. Over and over again. You can find a link to the PMVI on our site under P1 - Our Noise Laws. Yes, unbelievable but all true.
A Quieter O'ahu has been lobbying, and recommending that others do as well, our legislators to change the current laws to reflect language more easily understood and defined. Many municipalities, for example, have adopted adopted language such as "any motorcycle exhaust system capable of being heard at a distance greater than 50 feet from the end of the exhaust pipe shall be deemed and illegal exhaust system." Nothing ambiguous there. The distance is simply derived by taking a legal exhaust and measuring the distance from which it can't be heard - 50 feet for example. It would be hard for the authorities to argue that kind of language would be difficult to enforce. And beyond motorcycle exhausts such language could be applied to boom boxes, boom car stereos, mopeds, gas blowers, and any and all devices emitting unwanted noise levels.
Thanks for your note. Hope this lengthy reply provides some insights.
A Quieter O'ahu