And there are separate laws for cars and truck noise too. * California limits exhaust noise to 95 dBa: http://www.californiacarlaws.com/exhaust-noise/ http://w

And there are separate laws for cars and truck noise too. * California limits exhaust noise to 95 dBa: http://www.californiacarlaws.com/exhaust-noise/ http://www.californiacarlaws.com/exhaust-noise/ * Colorado has a subjective standard "prevent any excessive or unusual noise" https://law.justia.com/codes/colorado/2016/title-42/regulation-of-vehicles-and-traffic/article-4/part-2/section-42-4-225/ https://law.justia.com/codes/colorado/2016/title-42/regulati... * Connecticut has a pretty complicated scheme depending on the vehicle's weight and age, as well as the road surface: https://www.cga.ct.gov/2009/rpt/2009-R-0205.htm https://www.cga.ct.gov/2009/rpt/2009-R-0205.htm * Delaware has a subjective standard: "muffler in good working order and in accordance with manufacturer's specifications and in constant operation to prevent excessive or unusual noise." https://law.justia.com/codes/delaware/2015/title-21/chapter-43/subchapter-i/section-4311/ https://law.justia.com/codes/delaware/2015/title-21/chapter-... There are, of course, laws about other sources of noise too. Ask any college kid.