straight pipes are a BIT loud

RCW 46.37.390 said:

Mufflers, prevention of noise — Smoke and air contaminants — Standards — Definitions.


(1) Every motor vehicle shall at all times be equipped with a muffler in good working order and in constant operation to prevent excessive or unusual noise, and no person shall use a muffler cut-out, bypass, or similar device upon a motor vehicle on a highway.

(2)(a) No motor vehicle first sold and registered as a new motor vehicle on or after January 1, 1971, shall discharge into the atmosphere at elevations of less than three thousand feet any air contaminant for a period of more than ten seconds ..... (a bunch of B.S.)

(3) No person shall modify the exhaust system of a motor vehicle in a manner which will amplify or increase the noise emitted by the engine of such vehicle above that emitted by the muffler originally installed on the vehicle, and it shall be unlawful for any person to operate a motor vehicle not equipped as required by this subsection, or which has been amplified as prohibited by this subsection so that the vehicle's exhaust noise exceeds ninety-five decibels as measured by the Society of Automotive Engineers (SAE) test procedure J1169 (May, 1998). It is not a violation of this subsection unless proven by proper authorities that the exhaust system modification results in noise amplification in excess of ninety-five decibels under the prescribed SAE test standard. A court may dismiss an infraction notice for a violation of this subsection if there is reasonable grounds to believe that the vehicle was not operated in violation of this subsection.

This subsection (3) does not apply to vehicles twenty-five or more years old or to passenger vehicles being operated off the highways in an organized racing or competitive event conducted by a recognized sanctioning body.

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