Section 42-4-225 - Mufflers - prevention of noise(1) Every motor vehicle subject to registration and operated on a highway shall at all times be equipped with an adequate muffler in constant operation and properly maintained to prevent any excessive or unusual noise, and no such muffler or exhaust system shall be equipped with a cut-off, bypass, or similar device. No person shall modify the exhaust system of a motor vehicle in a manner which will amplify or increase the noise emitted by the motor of such vehicle above that emitted by the muffler originally installed on the vehicle, and such original muffler shall comply with all of the requirements of this section.(1.5) Any commercial vehicle, as defined in section 42-4-235 (1)(a), subject to registration and operated on a highway, that is equipped with an engine compression brake device is required to have a muffler.(2) A muffler is a device consisting of a series of chamber or baffle plates or other mechanical design for the purpose of receiving exhaust gas from an internal combustion engine and effective in reducing noise.(3) Any person who violates subsection (1) of this section commits a class B traffic infraction. Any person who violates subsection (1.5) of this section shall, upon conviction, be punished by a fine of five hundred dollars. Fifty percent of any fine for a violation of subsection (1.5) of this section occurring within the corporate limits of a city or town, or within the unincorporated area of a county, shall be transmitted to the treasurer or chief financial officer of said city, town, or county, and the remaining fifty percent shall be transmitted to the state treasurer, credited to the highway users tax fund, and allocated and expended as specified in section 43-4-205 (5.5)(a), C.R.S.(4) This section shall not apply to electric motor vehicles.L. 94: Entire title amended with relocations, p. 2260, § 1, effective 1/1/1995. L. 97: (4) added, p. 393, § 2, effective August 6. L. 2000: (1.5) added and (3) amended, p. 1100, § 1, effective August 2. L. 2005: (3) amended, p. 149, § 26, effective April 5.This section is similar to former § 42-4-222 as it existed prior to 1994, and the former § 42-4-225 was relocated to § 42-4-228 .