EPA cracks down on motorcycle defeat device for muffler emissions; takes aim at aftermarket makers

Residents annoyed and awakened by loud motorcycles might hope the recent federal crackdown on Harley-Davidson for selling equipment to bypass air pollution control units would carry over to aftermarket muffler manufacturers whose products fail to meet either national air pollution or noise standards.

But, don't get too optimistic.

U.S. Environmental Protection Agency (EPA) officials say they're focused on enforcement of air pollution regulations, not motorcycle noise standards, while Bettendorf police wrote just two tickets for loud motorcycle mufflers over the four-year period 2010 through 2014.

Consequently, motorcyclists with illegal mufflers – two to four times as loud as the federal limit of 80 decibels – operate with impunity throughout the city, often late at night and early in the morning.

"Motorcycles continue to be among the top environmental noise sources and people 'cannot find the peace and quiet in their homes that they deserve,'" The National Academy of Engineering (NAE) reported in 'Technology for a Quieter America' in 2010. "While the motorcycle noise regulations have been in place for more than three decades, enforcement has become less and less effective over the years.

"Although most motorcycle manufacturers comply with the EPA regulations by producing relatively quiet vehicles, the problem of excessive noise is primarly due to removal or tampering with their exhaust system, the manner in which some riders operate their motorcycles, and the ready availability of replacement exhaust systems that are noncompliant for street use."

August 25, 2013 report by the Institute of Noise Control Engineering of the USA, Inc.


In the EPA's most recent action last month involving Harley-Davidson, the EPA fined the company $12 million for selling so-called "super tuner" devices which enable the motorcycle engines to circumvent emission control equipment.

The EPA says it's investigating some aftermarket exhaust system makers, particularly those that operate without catalytic converters, because of their significantly higher emission of air pollutants.

"EPA believes available resources are best devoted towards enforcement of laws intended to protect the public against threats that have been shown to present a more severe risk to life and health, such as air pollution," the EPA stated in its response to questions from bettendorf.com."EPA does not consider that enforcement of private vehicle muffler laws rise to this level. We believe such enforcement is best left to local or state enforcement authorities."

Locally, though, enforcement is a very low priority because officers place a higher priority on "safety issues (speeding/reckless driving) instead of quality of life issues (noise)" a police spokesman said.

"I'm sure we rarely stop and issue warnings/citations solely based on loud mufflers," Justin Paul, of the Bettendorf Police Department, said. "I'm sure that some of our stops for loud mufflers are based on the noise being created from excessive acceleration, which could become a safety issue if not addressed.

"The police department must prioritize safety issues over quality-of-life issues," he said. "If you ask almost any neighborhood, they will tell you that vehicles speed through their neighborhood. It's hard to focus on noise complaints that aren't going to get anyone killed versus a speed/driving complaint that could end up injuring someone."

Few, if any, aftermarket mufflers sold through motorcycle dealers and online web sites meet EPA regulations for noise or emission of air pollution. Nearly all emit much higher noise than the 80 decibel limit set by federal regulations. In Iowa, the noise limit is 84 decibels.

*A note about decibel levels. Measuring sound with a decibel scale is logarithmic. So 90 decibels (a common reading for loud motorcycle mufflers) is twice as loud as 80 decibels (the EPA noise limit). For comparison, a telephone dial tone is 80 decibels, while a 90 decibel noise would be a train whistle at 500 feet or truck traffic. A jackhammer at 50 feet emits 95 decibels, while a normal conversation at three feet is 60 to 65 decibels.

More than a third of all motorcycles on the road today are estimated to be using aftermarket mufflers, installed either by their owners or local motorcycle shops.

"In its most recent survey from 2009, the Motorcycle Industry Council (MIC) has data from 1,120 on-highway motorcycle owners; 35 percent responded that they had modified or replaced the original exhaust system on their vehicles. Of those with modified/replaced exhaust systems, 36 percent responded that the noise increased 'greatly' and 37 percent responded that the noise increased 'slightly.' So, at least in the MIC sample of riders, 12 percent to 13 percent of the on-highway bikes may be operating with modified/replaced exhaust systems that produce greatly increased noise levels."

August 25, 2013 report by the Institute of Noise Control Engineering of the USA, Inc.


Many of the aftermarket replacement mufflers are "straight pipes," without a catalytic converter to remove air pollutants from exhaust emission. Such systems emit 10 times more air pollution compared to the factory mufflers with catalytic converters.

The main purpose of "straight pipes" and all other aftermarket exhaust systems is to make the motorcycle engines much louder. The oft-repeated, yet unproven, belief is very loud mufflers equate to improved safety for riders. There are no studies which show such a correlation, and motorcycle accident statistics show no such evidence.

So why can aftermarket manufacturers sell non-conforming mufflers while manufacturers like Honda, Harley-Davidson and Indian, must install mufflers that meet pollution and noise standards on bikes before they leave their factories?

All that aftermarket muffler makers must do is label units as either meeting federal noise and emission standards, or that the muffler is non-compliant and for use only for off-street racing purposes. But since there is no enforcement written into the EPA regulations, the agency has not made any effort to police the noise or pollution control standards on manufacturers of aftermarket motorcycle mufflers.

Many motorcycle mufflers are sold without any labels in direct contradiction to the EPA rules put in place in the 1980's.

Interestingly, motorcycle magazines – and even Harley-Davidson officials – have urged cyclists over the years to forego loud illegal mufflers, fearing the general public will demand tougher state and local ordinances and greater enforcement of existing noise and nuisance laws.

California is the only state to take a tougher approach to the illegal sale and use of non-compliant aftermarket mufflers. However, the motorcycle muffler makers simply warn buyers that some of their products shouldn't be used in California.

"When the Motorcycle Industry Council (MIC) tested more than 50 aftermarket systems in 2006 and 2007, Tom Austin of Sierra Research said none of the systems were technically compliant because they did not have the EPA label. Companies may not put in the effort to test and label their systems because the EPA’s website says that EPA has decided the principal responsibility for noise enforcement rests with state and local authorities. When their take-away impression is that no federal requirement exists, there is no incentive to comply."

August 25, 2013 report by the Institute of Noise Control Engineering of the USA, Inc.

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