Michigan State Representative Rick Jones has alerted SEMA that he will no longer pursue, in its current form, legislation (H.B. 5543) to ban vehicles equipped with replacement exhaust systems that differ from the design specifications of the original muffler. H.B. 5543 would also have prohibited the sale and use of exhaust systems that exceed an 80-decibel limit at a distance of 50 feet.

In its place, Representative Jones is considering SEMA model legislation that provides for the testing of vehicle exhaust noise to a standard adopted by the Society of Automotive Engineers (SAE) with an established noise limit of 95-decibels (SAE J1169). Under the SAE standard, a sound meter is placed 20 inches from the exhaust outlet at a 45 degree angle and the engine is revved to three quarters of maximum rated horsepower. The highest decibel reading is then recorded. To date, with the popular support of vehicle enthusiasts and related businesses, the model has been enacted in California, Washington State and Maine. This year, the SEMA model was introduced in Virginia.

 http://www.legislature.mi.gov/documents/2005-2006/billintroduced/House/htm/2006-HIB-5543.htm"