Mar. 31, 2008 – National sound test method coming closer to reality

By Neil Pascale
One of the industry’s biggest challenges and public relations headaches — how to deal with excessive motorcycle noise — is nearing an important milestone.
A science-based procedure for law enforcement to test exhaust systems to see if they fall within recommended noise levels could be adopted by a motorsports engineering standards group as early as this spring. That could then lead to a motorcycling first for the United States — a national, agreed-upon roadside method to test noise levels.
Currently, motorcyclists and national law enforcement are dealing with a patchwork of ways to assess a bike’s exhaust system noise output.
“It’s unfair to the riders and the industry and it’s frustrating,” said Pamela Amette, a Motorcycle Industry Council (MIC) vice president. “It’s not a good situation. You can go from city to city and not know you’re breaking the law.”
The MIC has worked for more than a year to address this situation, which has made national headlines after noise complaints have threatened to shut down major motorcycling rallies and events. Amette says the MIC and its industry partners are working with The Society of Automotive Engineers (SAE), a recognized, independent standards developing group that will ultimately adopt a sound testing procedure. The language of the new procedure is still being worked out, but Amette says she believes it will ultimately include two options. These would include an idle test and a RPM test, the first of which figures to be used most easily by law enforcement.
The idle test is similar to what a number of states are using to test off-highway vehicles. That procedure requires the measurement of sound from 20 inches away from the exhaust outlet at a 45-degree angle. The possible new on-road idle test would be somewhat different since the off-road method requires law enforcement to have specific engine details and providing law enforcement that for the myriad of street bikes on the market would not be realistic. But the simplicity of the test, which would require an officer to use a sound test meter, would be carried over to the on-highway version.
Once the SAE approves a testing procedure, then the MIC would work on proposing a recommended sound limit. Amette says the latter is not something the SAE does, believing that falls outside its jurisdiction.
Amette says the MIC will work with its committees and industry members, including aftermarket exhaust companies, to come up with a recommended sound limit for the MIC board’s consideration. That limit would then be communicated to law enforcement and national governing bodies. Amette believes those groups would be supportive of adopting the MIC-proposed sound limit if it’s science-based and supported by the industry. Amette notes both New York City and the California Highway Patrol are interested in the MIC’s future recommendations.
The idle test is expected to be one of two options states or cities could look at. The other option will include a set RPM test where noise levels will be measured at 2,000 RPM for bikes with less than three cylinders and more than four cylinders or at 5,000 RPM for bikes with three- and four-cylinder engines.
Ultimately it will be up to the governing body to decide if they want to use the idle test or RPM test or both.
Amette noted any recommended sound limits should be set so they don’t fail a bike meeting EPA’s current federal noise regulations, which new vehicles must pass before they are sold in the United States.
The EPA test is a much more complicated undergoing, one Amette said requires a laboratory setting plus a rider knowledgeable of the test’s exact methods.
Amette said. “Our goal is to try to curb the excessive noise and give enforcement a way to go after those who are causing the public nuisance problem, without creating havoc in the marketplace.”
“We’re trying to come up with something that will help satisfy the problem out there and be easy to use by the enforcement people.”

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