Exhaust Noise Laws By State

Code of Alabama

§ 32-5-216.  

(a) 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 annoying smoke, and no person shall use a muffler cut-out, bypass, a muffler without baffles or similar device upon a motor vehicle on a highway.

(b) The engine and power mechanism of every motor vehicle shall be so equipped and adjusted as to prevent the escape of excessive fumes or smoke.

§ 33-5-23.

(a)  The exhaust of every internal combustion engine used on any vessel shall be effectively muffled by equipment so constructed and used as to muffle the noise of the exhaust in a reasonable manner. The use of cutouts is prohibited, except for vessels competing in a regatta or official boat race, and for such vessels while on trial runs.

Regulated locally. 

Arizona Revised Statues

§ 28-955. Mufflers; noise and air pollution prevention; emissions control devices; civil penalty; exception 

(a)  A motor vehicle shall be equipped at all times with a muffler that is in good working order and that is in constant operation to prevent excessive or unusual noise.

(b)  A person shall not use a muffler cutout, bypass or similar device on a motor vehicle on a highway.

(c)  The engine and power mechanism of a motor vehicle shall be equipped and adjusted to prevent the escape of excessive fumes or smoke.

(d)  Beginning with motor vehicles and motor vehicle engines of the 1968 model year, motor vehicles and motor vehicle engines shall be equipped with emissions control devices that meet the standards established by the director of environmental quality.

(e)  A person who violates this section is subject to a civil penalty of at least one hundred dollars.

(f)  This section does not apply to an electrically powered motor vehicle. 

Arkansas Code

§27-37-601.  Noise or smoke producing devices prohibited.
 
(a)  Every motor vehicle shall, at all times, be equipped with a factory-installed muffler or one duplicating factory specifications, in good working order and in constant operation, to prevent excessive or unusual noise and annoying smoke.

(b)  No person shall use on a motor vehicle upon the public roads, highways, streets, or alleys of this state, nor shall any person sell for use on a motor vehicle upon the public roads, highways, streets, or alleys of this state, a muffler, other than as defined in subsection (a) of this section, cutout, bypass, similar device, or any type device which produces excessive or unusual noise or smoke.

§ 27-37-602. Cutouts prohibited.

(a)  The sale or use of cutouts on any motor-driven vehicle while on the public roads, highways, streets, and alleys of Arkansas is prohibited.

(b)  Any person found guilty in any court of Arkansas of violating this section, in whole or in part, shall be deemed guilty of a misdemeanor and subject to a fine of not less than ten dollars ($10.00) nor more than five hundred dollars ($500).

California Vehicle Code

 § 27150. Adequate muffler required

(a) Every motor vehicle subject to registration 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 muffler or exhaust system shall be equipped with a cutout, bypass, or similar device.

§ 27151.  Modification of exhaust systems

(a) A person shall not modify the exhaust system of a motor vehicle in a manner which will amplify or increase the noise emitted by the motor of the vehicle so that the vehicle is not in compliance with the provisions of Section 27150 or exceeds the noise limits established for the type of vehicle in Article 2.5 (commencing with Section 27200). A person shall not operate a motor vehicle with an exhaust system so modified.

(b) For the purposes of exhaust systems installed on motor vehicles with a manufacturer’s gross vehicle weight rating of less than 6,000 pounds, other than motorcycles, a sound level of 95 dbA or less, when tested in accordance with the most current SAE International standard, complies with this section. Motor vehicle exhaust systems or parts thereof include, but are not limited to, nonoriginal exhaust equipment.

(Amended by Stats. 2022, Ch. 295, Sec. 18. (AB 2956) Effective January 1, 2023.)

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.

Connecticut General Statutes

Sec. 14-80.  Mechanical equipment.

(a)  Each motor vehicle and the devices on such vehicle shall be operated, equipped, constructed and adjusted to prevent unnecessary or unusual noise.

(b)  Each motor vehicle operated by an internal combustion engine shall be equipped, except as hereinafter provided, with a muffler or mufflers designed to prevent excessive, unusual or unnecessary exhaust noise. The muffler or mufflers shall be maintained by the owner in good working order and shall be in use whenever the motor vehicle is operated. No person, including a motor vehicle dealer or repairer or a motorcycle dealer, shall install, and no person shall use, on a motor vehicle, a muffler or mufflers lacking interior baffle plates or other effective muffling devices, a gutted muffler, a muffler cutout or a straight exhaust except when the motor vehicle is operated in a race, contest or demonstration of speed or skill as a public exhibition pursuant to subsection (a) of section 14-164a, or any mechanical device which will amplify the noise emitted by the vehicle. No person, including a motor vehicle dealer or repairer or a motorcycle dealer, shall remove all or part of any muffler on a motor vehicle except to repair or replace the muffler or part for the more effective prevention of noise. No person shall use on the exhaust system or tail pipe of a motor vehicle any extension or device which will cause excessive or unusual noise.

(c)  The engine of every motor vehicle shall be equipped and adjusted to prevent excessive fumes or exhaust smoke.

(d)  All pipes carrying exhaust gases from the motor shall be constructed of, and maintained with, leak-proof metal. Exhaust pipes shall be directed from the muffler or mufflers toward the rear of the vehicle and shall be approximately parallel with the longitudinal axis of the vehicle and approximately parallel to the surface of the roadway, or shall be directed from the muffler upward to a location above the cab or body of the vehicle so that fumes, gases and smoke are directed away from the occupants of the vehicle. Exhaust pipes on a passenger vehicle shall extend to the extreme rear end of the vehicle's body, not including the bumper and its attachments to the body, or shall be attached to the vehicle in such a way that the exhaust pipes direct the exhaust gases to either side of the vehicle ensuring that fresh ambient air is located under the vehicle at all times. The Commissioner of Motor Vehicles may adopt regulations in accordance with the provisions of chapter 54 to establish safety standards for passenger vehicles equipped with exhaust pipes located in front of the rear axle.

(g)  Any person who violates any provision of this section shall be fined one hundred fifty dollars for each offense.

 Regs. Conn. State Agencies

Sec. 14-80a-4a. Allowable noise levels

Motor vehicle and snowmobile noise emissions when measured with the sound level measuring microphone located 50 feet (15.2 m) from the target point in accordance with the requirements of section 14-80a-7a shall not exceed the following specified values:

(a) Any motor vehicle or combination motor vehicle having a G.V.W.R. or G.C.W.R. of less than 10,000 pounds (4536 kg) including passenger motor vehicles:
Maximum Permissible Sound Level Readings dB(A)

Vehicles Manufactured:
Prior to Jan. 1, 1979: SOFT SITE: Highway Speed Limit 35 MPH or less – 76 dB(A). Highway Speed Limit above 35 MPH – 82 dB(A). HARD SITE: Highway Speed Limit 35 MPH or less – 78 dB(A). Highway Speed Limit above 35 MPH – 84 dB(A).

On and after Jan. 1, 1979: SOFT SITE: Highway Speed Limit 35 MPH or less – 72 dB(A). Highway Speed Limit above 35 MPH – 79 dB(A). HARD SITE: Highway Speed Limit 35 MPH or less – 74 dB(A). Highway Speed Limit above 35 MPH – 81 dB(A).

 Delaware Code

Title 11 § 4311. Mufflers; cutout prohibited 

(a) No person shall drive a motor vehicle, including a motorcycle, on a highway, including residential streets, unless such motor vehicle or motorcycle is equipped with a muffler in good working order and in accordance with manufacturer's specifications and in constant operation to prevent excessive or unusual noise.

(b) No person shall use a "muffler cutout" on any motor vehicle upon a highway.

(c)  It shall be unlawful to sell or offer for sale any muffler without interior baffle plates or other effective muffling devices or to sell or offer for sale any "gutted muffler," "muffler cutout" or "straight exhaust."

(d)  The provisions of this section shall only apply if there is not a violation of § 4311A of this title.

Title 21 § 2197 Street Rods

13) Exhaust systems--Every street rod shall be equipped with an exhaust system that is free of leaks including the exhaust manifolds (including headers), the piping leading from the flange of the exhaust manifold(s) and the tail piping.

Exhaust systems on street rods shall discharge the exhaust fumes at a location to the rear of the vehicle body or direct the exhaust fumes outward from the side of the vehicle body at a location rearward of any operable side windows. No part of the exhaust system shall pass through any area of the vehicle that is used as a passenger carrying compartment. Every street rod must be equipped with a muffler in good working order and in constant operation to prevent excessive or unusual noise. Muffler cutouts or mufflers without internal baffle plates are prohibited.

Florida Statutes

§ 316.272.  Exhaust systems, prevention of noise 

(1)  Every motor vehicle shall at all times be equipped with an exhaust system in good working order and in constant operation, including muffler, manifold pipe, and tailpiping to prevent excessive or unusual noise. In no event shall an exhaust system allow noise at a level which exceeds a maximum decibel level to be established by regulation of the Department of Environmental Protection as provided in s. 403.061(11) in cooperation with the Department of Highway Safety and Motor Vehicles. No person shall use a muffler cutout, bypass or similar device upon a vehicle on a highway.

(2)  The engine and power mechanism of every motor vehicle shall be so equipped and adjusted as to prevent the escape of excessive fumes or smoke.

(3)  A violation of this section is a noncriminal traffic infraction, punishable as a nonmoving violation as provided in chapter 318. 
 
§ 316.293 Motor Vehicle Noise

(2) Operating noise limits.-- No person shall operate or be permitted to operate a vehicle at any time or under any condition of roadway grade, load, acceleration, or deceleration in such a manner as to generate a sound level in excess of the following limit for the category of motor vehicle and applicable speed limit at a distance of 50 feet from the center of the lane of travel under measurement procedures established under subsection (3).

(a) For motorcycles other than motor-driven cycles: Before January 1, 1979 – Speed Limit 35 mph or less: 82 dBA. Speed Limit over 35 mph: 86 dBA. On or after January 1, 1979 – Speed Limit 35 mph or less: 78 dBA. Speed Limit over 35 mph: 82 mph.
(b) For any motor vehicle with a GVWR or GCWR of 10,000 pounds or more: On or after January 1, 1979 – Speed Limit 35 mph or less: 86 dBA. Speed Limit over 35 mph: 90 mph.
(c) For motor-driven cycles and any other motor vehicle not included in paragraph (a) or paragraph (b): Before January 1, 1979 – Speed Limit 35 mph or less: 76 dBA. Speed Limit over 35 mph: 82 dBA. On or after January 1, 1979 – Speed Limit 35 mph or less: 72 dBA.
Speed Limit over 35 mph: 79 mph.

(3) Measurement procedures. --The measurement procedures for determining compliance with this section shall be established by regulation of the Department of Environmental Protection as provided in s. 403.415(9), in cooperation with the department. Such regulations shall include the selection of measurement sites and measurement procedures and shall take into consideration accepted scientific and professional methods for the measurement of vehicular sound levels. The measurement procedures may include adjustment factors to be applied to the noise limit for measurement distances of other than 50 feet from the center of the lane of travel.
(4) Applicability. --This section applies to the total noise from a vehicle and shall not be construed as limiting or precluding the enforcement of any other provisions of this chapter relating to motor vehicle mufflers for noise control.
(5) Noise abatement equipment modifications. –

(a) No person shall modify the exhaust system of a motor vehicle or any other noise-abatement device of a motor vehicle operated or to be operated upon the highways of this state in such a manner that the noise emitted by the motor vehicle is above that emitted by the vehicle as originally manufactured.
(b) No person shall operate a motor vehicle upon the highways of the state with an exhaust system or noise-abatement device so modified.

(6) Exempt vehicles. --The following are exempt from the operation of this act:

(a) Emergency vehicles operating as specified in s. 316.072(5)(a).
(b) Any motor vehicle engaged in a professional or amateur sanctioned, competitive sports event for which admission or entry fee is charged, or practice or time trials for such event.
(c) Any motor vehicle engaged in a manufacturer's engineering, design, or equipment test.
(d) Construction or agricultural equipment either on a job site or traveling on the highways.

(7) Violations.--A violation of this section is a noncriminal traffic infraction, punishable as a nonmoving violation as provided in chapter 318.

Official Code of Georgia

§ 40-8-71.  Exhaust system; prevention of noise, smoke, and fumes 

(a) Every motor vehicle shall at all times be equipped with an exhaust system, in good working order and in constant operation, meeting the following specifications:
(1) The exhaust system shall include the piping leading from the flange of the exhaust manifold to and including the muffler or mufflers and tail pipes;
(2) The use of flexible pipe shall be prohibited except on diesel tractors or according to manufacturers' original specifications;
(3) The exhaust emission point shall extend beyond the rear or outside of the passenger compartment. The trunk shall be considered as part of the passenger compartment;
(4) The exhaust system and its elements shall be securely fastened, including the consideration of missing or broken hangers; and
(5) There shall be no part of the exhaust system passing through the passenger compartment or any exposed stack so located that any individual entering or leaving the vehicle may be burned.
(b) The engine and power mechanism of every motor vehicle shall be so equipped and adjusted as to prevent the escape of excessive fumes or smoke.

(c) It shall be unlawful for any person to sell or offer for sale any muffler which causes excessive or unusual noise or annoying smoke or any muffler cutout, bypass, or similar device for use on a motor vehicle or for any person to use, to sell, or to offer for sale any motor vehicle equipped with any such muffler, muffler cutout, bypass, or similar device. Any person violating this subsection shall be guilty of a misdemeanor.

Hawaii Revised Statutes

§ 291-24.5. Motor vehicle muffler.

(a) No person shall use on a public highway, sell, alter or install a muffler which will noticeably increase the noise emitted by a motor vehicle above that emitted by the vehicle as equipped from the factory.

(b) Any violation of this section shall constitute a violation and shall be enforceable by police officers. The fine for this violation shall be not less than $25 nor more than $250 for each separate offense. Any person who violates the provisions of this section may be issued a summons or citation for such violation.

Idaho Code

§ 49-937. Mufflers, prevention of noise 

(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 annoying smoke, and no person shall use a muffler cut-out, bypass, or similar device upon a motor vehicle on a highway. When any motor vehicle was originally equipped with a noise suppressing system or when any motor vehicle is required by law or regulation of this state or the federal government to have a noise suppressing system, that system shall be maintained in good working order. No person shall disconnect any part of that system except temporarily in order to make repairs, replacements or adjustments, and no person shall modify or alter that system or its operation in any manner, except to conform to the manufacturer's specifications. No person shall knowingly operate and no owner shall knowingly cause or permit to be operated any motor vehicle originally equipped or required by any law or regulation of the state or the federal government to be equipped with a noise suppressing system while any part of that system is disconnected or while that system or its operation is modified or altered in any manner, except to conform to the manufacturer's specifications.

(2) The engine and power mechanism of every motor vehicle shall be so equipped and adjusted as to prevent the escape of excessive fumes or smoke.

(3) No person shall modify the exhaust system of a motor vehicle or a motorcycle in a manner which will amplify or increase the noise of the vehicle or motorcycle above that emitted by the muffler originally installed on the vehicle by the manufacturer.

(4) A showing that the sound made by a passenger motor vehicle or motorcycle exceeds the maximum allowable decibel level shall be prima facie evidence of a violation of subsection (1) of this section.

(5) No person shall sell, offer for sale, or install any noise suppressing system or device which will produce excessive or unusual noise.

Illinois Vehicle Code

§ 625 ILCS 5/12-602.  Mufflers, prevention of noise 

Every motor vehicle driven or operated upon the highways of this State shall at all times be equipped with an adequate muffler or exhaust system in constant operation and properly maintained to prevent any excessive or unusual noise. No such muffler or exhaust system shall be equipped with a cutout, 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 of such vehicle above that emitted by the muffler originally installed on the vehicle, and such original muffler shall comply with all the requirements of this Section. 

Indiana Code

9-19-8-2.  Muffler to be free from visually discernible conditions.

A motor vehicle must be equipped with a muffler free from the following visually discernible conditions:
(1) Exhaust gas leaks.
(2) Alteration of muffler elements.
(3) Deterioration of muffler elements.

9-19-8-3.  Muffler or other noise dissipative device to meet certain conditions.

A motor vehicle must be equipped with a muffler or other noise dissipative device that meets the following conditions:
(1) Is in good working order.
(2) Is in constant operation to prevent excessive noise.

9-19-8-4.  Equipment prohibited.

A motor vehicle may not be equipped with any of the following:
(1) A muffler cutout.
(2) A bypass.
(3) Any similar device.

Iowa Code

§ 321.436 Mufflers, prevention of noise.

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 annoying smoke, and no person shall use a muffler cutout, bypass or similar device upon a motor vehicle on a highway.

Kansas Statutes

§ 8-1739 Mufflers and noise suppressing systems.

 (a) Every vehicle shall be equipped, maintained and operated so as to prevent excessive or unusual noise. Every motor vehicle at all times shall be equipped with a muffler or other effective noise suppressing system in good working order and in constant operation, and no person shall use a muffler cut-out, bypass or similar device.

(b) The engine and power mechanism of every motor vehicle shall be so equipped and adjusted as to prevent the escape of excessive fumes or smoke.

Kentucky Revised Statutes

§ 189.020.  Equipment of vehicle not to be nuisance or menace.

Every vehicle when on a highway shall be so equipped as to make a minimum of noise, smoke or other nuisance, to protect the rights of other traffic, and to promote the public safety.
  
§ 189.140.  Mufflers -- Noise regulation.

(1) Every motor vehicle with an internal-combustion, steam or air motor shall be equipped with a suitable and efficient muffler. No person while on a highway shall operate a motor vehicle with the muffler cut out or removed. No cutout shall be so arranged or connected as to permit its operation or control by the driver of any motor vehicle while in position for driving.

(2) No person shall modify the exhaust system of a motor vehicle or an off highway 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. The original muffler shall comply with all of the noise requirements of KRS Chapter 224 and regulations promulgated pursuant thereto. No person shall operate a motor vehicle with an exhaust system so modified.

§ 224.30-190 Modification of motor vehicle exhaust system to increase noise prohibited.

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 the original muffler shall comply with all of the requirements of this chapter. No person shall operate a motor vehicle with an exhaust system so modified. 

Louisiana Revised Statutes

§ 32:352. Mufflers; requirements; prevention of excessive noise, fumes and smoke 

A. 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.

B. No person shall use a muffler cut-out, bypass or similar device upon a motor vehicle on a highway of this state.

C. The engine and power mechanism of every motor vehicle shall be so equipped and adjusted as to prevent the escape of excessive fumes or smoke.

§ 32:353. Modification of exhaust systems 

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 the original muffler shall comply with all of the requirements of R.S. 32:352.

29-A Maine Revised Statutes

§ 1912.  Mufflers

1. Muffler required.  A person may not operate a motor vehicle unless that vehicle is equipped with an adequate muffler properly maintained to prevent excessive or unusual noise. For purposes of this subsection, "excessive or unusual noise" includes motor noise emitted by a motor vehicle that is noticeably louder than similar vehicles in the environment.

2. Cutouts prohibited.  A muffler or exhaust system may not be equipped with a cutout, bypass or similar device.

3. Amplification prohibited.  A person may not operate a motor vehicle with an exhaust system that has been modified when the result of that modification is the amplification or increase of noise emitted by the motor above that emitted by the muffler originally installed on the vehicle.

4. Exhaust system fastened to engine.  The entire exhaust system must be complete, without leakage and securely fastened to the engine block and frame.

6. Defense for noise violations by motor vehicles.  The following are defenses to a violation of subsection 1 or 3.

    (a)  If a muffler or exhaust system of a motor vehicle as defined in section 101, subsection 42, not including a motorcycle, does not emit noise in excess of 95 decibels as measured in accordance with standards and specifications outlined in standard J-1169 adopted by the Society of Automotive Engineers in May 1998, subsections 1 and 3 do not apply. A person served with a Violation Summons and Complaint charging a violation of subsection 1 or 3 must provide satisfactory evidence that the muffler or exhaust system does not emit noise in excess of 95 decibels as measured in accordance with standards and specifications outlined in standard J-1169 adopted by the Society of Automotive Engineers in May 1998. Measurements must be made by a participating certified inspection station.

Maryland Transportation Code

§ 22-402. Mufflers; prevention of noise; discharge of smoke; maximum period of idling 

(a) Mufflers. -- Every motor vehicle with an internal combustion engine shall be equipped with an exhaust muffler system in good working order and in constant operation to prevent excessive or unusual noise, and no person may use a muffler cutout, bypass, or similar device on a motor vehicle on a highway. Noise levels in excess of those adopted by the Administrator under § 22-601 of this title are excessive.

(b) Prevention of noise. -- A person may not use on the exhaust or "tail pipe" of a motor vehicle any extension or other device to cause excessive or unusual noise.

(c) Discharge of smoke; maximum period of idling. --
(1) No motor vehicle may be operated, nor may the owner or lessee of a motor vehicle permit it to be operated, on any highway in this State unless the engine power and exhaust mechanism is equipped, adjusted, and operated to prevent:

(i) The discharge of clearly visible smoke (comparable to smoke equal to or darker in shade than that designated as No. 1 of the Ringelmann Chart as published by the U.S. Bureau of Mines) in the exhaust emissions within the proximity of the exhaust outlet for more than 10 consecutive seconds; and
(ii) The discharge of smoke from any other part of the engine in such amounts and of such opacity as to partially obscure persons or objects from view.

(2) In this subsection, "smoke" means small gasborne and airborne particles, exclusive of water vapor, from a process of combustion in sufficient numbers to be observable.

(5) This subsection does not apply to Class L (historic) vehicles.

(d) "Muffler" defined. -- In this section, "muffler" means a device designed for and effective in reducing noise while permitting the flow of gases.

(e) Leakproof construction. -- All mufflers and exhaust pipes carrying exhaust gases from the motor shall be of leakproof construction.
  
§ 22-609. Modification of exhaust system 

(a) Modification that increases sound prohibited. -- A person may not modify the exhaust system or any other noise abatement device of a motor vehicle driven or to be driven on any highway in this State in such a way that the noise emitted by the vehicle exceeds that emitted by the vehicle as originally manufactured.

(b) Operation of improperly modified vehicle prohibited. -- A person may not drive on any highway in this State a motor vehicle with an exhaust system or noise abatement device modified in a way prohibited by subsection (a) of this section.

Laws of Massachusetts: General Laws

Chapter 90 § 7.  Brakes, Lights and Other Equipment; Standards.

Every motor vehicle so operated shall be provided with a muffler or other suitable device to prevent unnecessary noise and with a suitable bell, horn or other means of signaling, with suitable lamps, and with a lock, key or other device to prevent such vehicle from being set in motion by unauthorized persons, or otherwise contrary to the will of the owner or person in charge thereof.
  
Chapter 90 § 16. Offensive or illegal operation of motor vehicles

No person shall use a muffler cut-out or by-pass. No person shall operate a motor vehicle on any way which motor vehicle is equipped (1) with a muffler from which the baffle plates, screens or other original internal parts have been removed and not replaced; or (2) with an exhaust system which has been modified in a manner which will amplify or increase the noise emitted by the exhaust.

Michigan Complied Laws Service

§ 257.707b.  Exhaust system; requirements.

(1) A motor vehicle, while being operated on a highway or street, shall be equipped with an exhaust system in good working order to prevent excessive or unusual noise and shall be equipped to prevent noise in excess of the limits established in this act.

(2) For purposes of sections 707a to 707f, a motor vehicle does not include a special mobile equipment.

§ 257.707c.  Noise limitations; prohibitions.

 (1) After April 1, 1978, a motor vehicle shall not be operated or driven on a highway or street if the motor vehicle produces total noise exceeding 1 of the following limits at a distance of 50 feet except as provided in subdivisions (b)(iii) and (c)(iii):

(a) A motor vehicle with a gross weight or gross vehicle weight rating of 8,500 pounds or more, combination vehicle with gross weight or gross vehicle weight ratings of 8,500 pounds or more.
(i) Ninety DBA if the maximum lawful speed on the highway or street is greater than 35 miles per hour.
(ii) Eighty-six DBA if the maximum lawful speed on the highway or street is not more than 35 miles per hour.
(iii) Eighty-eight DBA under stationary run-up test.
(c) A motor vehicle or a combination of vehicles towed by a motor vehicle not covered in subdivision (a) or (b):
(i) Eighty-two DBA if the maximum lawful speed on the highway or street is greater than 35 miles per hour.
(ii) Seventy-six DBA if the maximum lawful speed on the highway or street is not more than 35 miles per hour.
(iii) Ninety-five DBA under stationary run-up test 20 inches from the end of the tailpipe.

(2) A dealer shall not sell or offer for sale for use upon a street or highway in this state a new motor vehicle manufactured after April 1, 1978, which produces a maximum noise exceeding the following limits:
(a) A motor vehicle with a gross vehicle weight rating of 8,500 pounds or more–83 DBA.
(c) A motor vehicle not covered in subdivision (a) or (b)--80 DBA.

(3) A person shall not operate a vehicle on a highway or street if the vehicle has a defect in the exhaust system which affects sound reduction, is not equipped with a muffler or other noise dissipative device, or is equipped with a cutout, bypass, amplifier, or a similar device.

(4) A person, either acting for himself or herself or as the agent or employee of another, shall not sell, install, or replace a muffler or exhaust part that causes the motor vehicle to which the muffler or exhaust part is attached to exceed the noise limits established by this act or a rule promulgated under this act.

(5) A person shall not modify, repair, replace, or remove a part of an exhaust system causing the motor vehicle to which the system is attached to produce noise in excess of the levels established by this act, or operate a motor vehicle so altered on a street or highway.

(6) A dealer shall not sell a used or secondhand motor vehicle for use upon a street or highway which is not in compliance with this act.

Minnesota Statutes

§ 169.69 Muffler

Every motor vehicle shall at all times be equipped with a muffler in good working order which blends the exhaust noise into the overall vehicle noise and is in constant operation to prevent excessive or unusual noise, and no person shall use a muffler cutout, bypass, or similar device upon a motor vehicle on a street or highway. The exhaust system shall not emit or produce a sharp popping or crackling sound. Every motor vehicle shall at all times be equipped with such parts and equipment so arranged and kept in such state of repair as to prevent carbon monoxide gas from entering the interior of the vehicle.

No person shall have for sale, sell or offer for sale or use on any motor vehicle any muffler that fails to comply with the specifications as required by the commissioner of public safety. 

Mississippi Code

§ 63-7-55. Mufflers 

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 annoying smoke. No person shall use a muffler cutout, bypass or similar device upon a motor vehicle on a highway. 

Missouri Statutes 

§ 307.170. Other equipment of motor vehicles--violations, penalty 

2.  Muffler cutouts: Muffler cutouts shall not be used and no vehicle shall be driven in such manner or condition that excessive and unnecessary noises shall be made by its machinery, motor, signaling device, or other parts, or by any improperly loaded cargo. The motors of all motor vehicles shall be fitted with properly attached mufflers of such capacity or construction as to quiet the maximum possible exhaust noise as completely as is done in modern gas engine passenger motor vehicles. Any cutout or opening in the exhaust pipe between the motor and the muffler on any motor vehicle shall be completely closed and disconnected from its operating lever, and shall be so arranged that it cannot automatically open, or be opened or operated while such vehicle is in motion.

Montana Code

 § 61-9-403. Mufflers--prevention of noise

(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 annoying smoke, and no
person shall use a muffler cutout, bypass, or similar device upon a motor vehicle on a highway.

(2) The engine and power mechanism of every motor vehicle shall be so equipped and adjusted as to prevent the escape of excessive fumes or smoke.

§ 61-9-435 Exhaust noise limitation.

(1)  Except as provided in subsection (3), a person may not operate a motor vehicle with an exhaust system that emits a noise in excess of 95 decibels, as measured by the society of automotive engineers' standard j1169 (May 1998).

(2)  A person charged with violating this section may not be convicted if the person had reasonable grounds to believe that the vehicle was not operated in violation of the standard in subsection (1).

(3)  This section does not apply to a motorcycle or quadricycle that is subject to 61-9-418. 

Revised Statutes of Nebraska

§ 60-6,286. Muffler or noise-suppressing system; prevention of fumes and smoke; requirements 

Every vehicle shall be equipped, maintained, and operated so as to prevent excessive or unusual noise. No person shall drive a motor vehicle on a highway unless such motor vehicle is equipped with a muffler or other effective noise-suppressing system in good working order and in constant operation. It shall be unlawful to use a muffler cutout, bypass, or similar device on any motor vehicle upon a highway.

The engine and power mechanism of every motor vehicle shall be so equipped and adjusted as to prevent the escape of excessive fumes or smoke.

§ 60-6,371. Exhaust or intake muffler; change; increase of noise; prohibited 

No person shall modify or change the exhaust muffler, the intake muffler, or any other noise-abatement device of a motor vehicle in a manner such that the noise emitted by the motor vehicle is increased above that emitted by the vehicle as originally manufactured. Procedures used to establish compliance with this section shall be those used to establish compliance of a new motor vehicle with the requirements of sections 60-6,363 to 60-6,374.

Nevada Revised Statutes

§ 484D.415 Mufflers: Prevention of emissions.

1.  Every motor vehicle shall at all times be equipped with a muffler in good working order and in constant operation to prevent emissions greater than those allowed by rules and regulations established by the Department. No person shall use a muffler cutout, bypass or similar device upon a motor vehicle on a highway.

2.  The engine and power mechanism of every motor vehicle shall be so equipped and adjusted as to prevent the escape of excessive fumes or smoke.

New Hampshire Revised Statutes

266:59 Muffler; Prevention of Noise.

I.  Every motor vehicle shall at all times be equipped with a muffler as defined in RSA 259:66, in good working order and in constant operation to prevent excessive or unusual noise, and no person shall use a muffler cutout, bypass or similar device upon a motor vehicle on a way.

II.  The engine and power mechanism of every motor vehicle shall be so equipped and adjusted as to prevent the escape of excessive fumes, smoke, flame, gas, oil or fuel residue.

III.  [Repealed.]

IV.  No person shall operate a motor vehicle with a straight pipe exhaust system; "straight pipe exhaust system" means any straight-through exhaust system that does not contain baffles or otherwise does not meet the definition of muffler in RSA 259:66. Any person who violates the provisions of this paragraph shall be guilty of a violation and shall be fined not less than $100 for a first offense, not less than $250 for a second offense in a calendar year, and not less than $500 for a third or subsequent offense in a calendar year.

New Jersey Statutes

§ 39:3-70. Mufflers 

Every motor vehicle having a combustion motor 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.

New Mexico Statutes

§ 66-3-844.  Mufflers; prevention of noise; emission control devices 

A.  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 cutout, bypass or similar device upon a motor vehicle on a highway.

B.  The muffler, emission control equipment or device, engine and power mechanism of every motor vehicle shall be so equipped and adjusted as to prevent the escape of excessive fumes or smoke.

C.  Every registered gasoline-fueled motor vehicle manufactured or assembled, commencing with the 1968 models, shall at all times be equipped and maintained in good working order with the factory-installed devices and equipment or their replacements designed to prevent, reduce or control exhaust emissions or air pollution.

New York Consolidated Laws Service

Vehicle and Traffic Law § 375.  Equipment

 31.  Mufflers and exhaust systems. Prevention of noise. (a) Every motor vehicle, operated or driven upon the highways of the state, shall at all times be equipped with an adequate muffler and exhaust system 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-out, bypass, or similar device. No person shall modify the muffler or exhaust system of a motor vehicle in a manner which will amplify or increase the noise emitted by the motor or exhaust system of such vehicle above that emitted by the muffler or exhaust system originally installed on the vehicle and such original muffler and exhaust system shall comply with all the requirements of this section.

(b) No person shall, in the state, sell, offer for sale or install any of the following for the muffler or exhaust system of a motor vehicle: a cut-out,  bypass, or a similar device which will amplify or increase the noise emitted by the motor or exhaust system of such vehicle above  that emitted  by  the  muffler  or exhaust system originally installed on the vehicle.

A muffler is a device consisting of a series of chambers or baffle plates, or other mechanical design for the purpose of receiving exhaust gas from an internal combustion engine, and effective in reducing noise.

An exhaust system is a series of mechanical devices for the purpose of receiving exhaust gas from an internal combustion engine and expelling it into the atmosphere.

§ 386. Motor vehicle sound level limits

c. It shall be unlawful for any person to operate or cause of be operated on a public highway any motor vehicle or combination of vehicles, except motorcycles, with a maximum gross weight of ten thousand pounds or less, at any time, under any condition of grade, load, acceleration or deceleration in such a manner as to exceed the applicable A-weighted sound level set forth in table II. The maximum allowable sound levels in table II are based on a sound level measured at, or adjusted to, a distance of fifty feet from the center of the lane in which the motor vehicle is traveling:

TABLE II
MAXIMUM ALLOWABLE A-WEIGHTED SOUND LEVELS
Maximum Speed Limit
35 miles per hour or less: 76 dB(A)
Over 35 miles per hour: 82 dB(A)

4. The commissioner of environmental conservation shall promulgate regulations establishing the measurement procedures and instrumentation to be utilized in the enforcement of this section.
a. These procedures shall allow, to the extent feasible, motor vehicle sound measurements to be accomplished in reasonably confined areas such as residential areas of urban cities and may provide for sound measurement at distances other than fifty feet and in the vicinity of sound reflecting surfaces.
b. The regulations shall take into consideration recognized scientific and professional standards for the measurement of vehicular sound levels.
5. The provisions of this section shall not apply to vehicles and implements or combinations thereof used solely for farm purposes, nor to authorized emergency vehicles.

General Statute of North Carolina

§ 20-128. Exhaust system and emissions control devices 

(a) No person shall drive a motor vehicle on a highway unless such motor vehicle is equipped with a muffler, or other exhaust system of the type installed at the time of manufacture, in good working order and in constant operation to prevent excessive or unusual noise, annoying smoke and smoke screens.

(b) It shall be unlawful to use a "muffler cut-out" on any motor vehicle upon a highway.

(c) No motor vehicle registered in this State that was manufactured after model year 1967 shall be operated in this State unless it is equipped with emissions control devices that were installed on the vehicle at the time the vehicle was manufactured and these devices are properly connected.

(d) The requirements of subsection (c) of this section shall not apply if the emissions control devices have been removed for the purpose of converting the motor vehicle to operate on natural or liquefied petroleum gas or other modifications have been made in order to reduce air pollution and these modifications are approved by the Department of Environment and Natural Resources.

North Dakota Century Code

§ 39-21-37.  Muffler -- Prevention of noise and smoke.

1. Every motor vehicle must at all times be equipped with a muffler in good working order and in constant operation to prevent excessive or unusual noise and annoying smoke, and no person may use a muffler cutout, bypass, or similar device upon a motor vehicle on a highway.

2. The engine and power mechanism of every motor vehicle must be so equipped and adjusted as to prevent the escape of excessive fumes or smoke.

Ohio Revised Code

§ 4513.22. Mufflers; excessive smoke or gas 

(A) Every motor vehicle and motorcycle with an internal combustion engine shall at all times be equipped with a muffler which is in good working order and in constant operation to prevent excessive or unusual noise, and no person shall use a muffler cutout, by-pass, or similar device upon a motor vehicle on a highway. Every motorcycle muffler shall be equipped with baffle plates.
No person shall own, operate, or have in the person's possession any motor vehicle or motorcycle equipped with a device for producing excessive smoke or gas, or so equipped as to permit oil or any other chemical to flow into or upon the exhaust pipe or muffler of such vehicle, or equipped in any other way to produce or emit smoke or dangerous or annoying gases from any portion of such vehicle, other than the ordinary gases emitted by the exhaust of an internal combustion engine under normal operation.
(B) Whoever violates this section is guilty of a minor misdemeanor.

§ 4513.221 Noise control

(A) The board of county commissioners of any county, and the board of township trustees of any township subject to section 505.17 of the Revised Code, may regulate passenger car and motorcycle noise on streets and highways under their jurisdiction. Such regulations shall include maximum permissible noise limits measured in decibels, subject to the requirements of this section.
(B) Regulations establishing maximum permissible noise limits measured in decibels shall prohibit the operation, within the speed limits specified herein, of a passenger car or motorcycle of a type subject to registration at any time or under any condition of load, acceleration, or deceleration in such manner as to exceed the following maximum noise limits, based on a distance of not less than fifty feet from the center of the line of travel:
(1) For passenger cars:

(a) When operated at a speed of thirty-five miles per hour or less, a maximum noise limit of seventy decibels;
(b) When operated at a speed of more than thirty-five miles per hour, a maximum noise limit of seventy-nine decibels.
(C) Maximum noise limits established pursuant to division (B) of this section shall be measured on the "A" scale of a standard sound level meter meeting the applicable requirements for a type 2 sound level meter as defined in American national standards institute standard S1.4--1983, or the most recent revision thereof. Measurement practices shall be in substantial conformity with standards and recommended practice established by the society of automotive engineers, including SAE standard J 986 A NOV81, SAE standard J 366 MAR85, SAE standard J 331 A, and such other standards and practices as may be approved by the federal government.
 (F) Whoever violates any maximum noise limit established as provided in division (B) of this section or any of the prohibitions authorized in division (E) of this section is guilty of a minor misdemeanor. Fines collected under this section by the county shall be paid into the county general fund, and such fines collected by the township shall be paid into the township general fund.

No regulation adopted under this section shall apply to commercial racetrack operations.

Oklahoma Statutes

Title 47 § 12-402. Mufflers, Prevention of Noise

A.  Every vehicle shall be equipped, maintained, and operated so as to prevent excessive or unusual noise. Every motor vehicle shall at all times be equipped with a muffler or other effective noise-suppressing system in good working order and in constant operation, and no person shall use a muffler cut-out, bypass or similar device. No person shall modify the exhaust system of a motor vehicle in any manner which will amplify or increase the noise or sound emitted louder than that emitted by the muffler originally installed on the vehicle.

B.  The engine and power mechanism of every motor vehicle shall be so equipped and adjusted as to prevent the escape of excessive fumes or smoke, or both.

Oregon Revised Statutes

§ 815.250 Operation without proper exhaust system; exemptions; penalty.

(1) A person commits the offense of operation without proper exhaust system if the person drives or moves on any highway or owns and causes or knowingly permits to be driven or moved on any highway a motor vehicle that is not equipped with an exhaust system that meets the requirements under this section.

(2) An exhaust system only meets the requirements of this section if all of the following apply:

(a) The exhaust system must be in good working order.
(b) The exhaust system must be in constant operation.
(c) The exhaust system must meet noise emission standards determined by the Department of Environmental Quality to be substantially equivalent to the following standards based upon a stationary test conducted at a distance of 25 feet in accordance with procedures established by the Department of Environmental Quality:
_______________________________________________________________________

I. Vehicle type: Motor vehicles required to establish a registration weight under ORS 803.430 and commercial buses
Maximum level, dBA: 94 dBA if model year before 1976; 91 dBA if model year 1976 and after
  
III. Vehicle type: motor vehicles not described under I or II
Maximum level, dBA: 92 dBA if model year before 1976; 88 dBA if model year 1976 and after
________________________________________________________________________
(3) This section does not apply to the following vehicles:
(a) Vehicles of special interest that are registered under ORS 805.020 and that are:
(A) Equipped with original manufacturer's equipment and accessories, or their equivalent, and that are maintained in safe operating condition; or
(B) Street rods that conform to ORS 815.107.
(b) Road machinery, road rollers or farm tractors.
(c) Antique motor vehicles that are maintained as collectors' items and used for exhibitions, parades, club activities and similar uses, but not used primarily for the transportation of persons or property.
(4) The court in its discretion may dismiss a citation issued for violation of the offense described in this section if evidence is presented that the exhaust system complies with or has been repaired or modified to comply with the requirements under this section.
(5) The offense described in this section, operation without proper exhaust system, is a Class C traffic violation.

75 Pennsylvania Statues

§ 157.11. Vehicular noise limits.

(a) Prohibition. No person shall operate either a motor vehicle or combination of vehicles of a type subject to registration at any time or under any condition of grade, load, acceleration or deceleration in such a manner as to exceed the following noise limit for the category of motor vehicle within the speed limits specified in Table 1.

Table 1
Maximum Permissible Sound Level Readings (decibel (A)) Highway operations test

(1) Any motor vehicle with a manufacturers gross vehicle weight rating of 6,000 pounds or more and any combination of vehicles towed by such motor vehicle – Soft Site: 35 mph or less: 86. Above 35 mph: 90. Hard Site: 35 mph or less: 88. Above 35 mph: 92.
(2) Any motorcycle other than a motor-driven cycle – Soft Site: 35 mph or less: 82. Above 35 mph: 86. Hard Site: 35 mph or less: 84. Above 35 mph: 88.
3) Any other motor vehicle and any combination of vehicles towed by such motor vehicles – Soft Site: 35 mph or less: 76. Above 35 mph: 82. Hard Site: 35 mph or less: 78. Above 35 mph: 84.

 (b) Measurement distance. The noise limits established by this section shall be based on a distance of 50 feet from the center lane of travel within the speed limit specified in this section. Measurements at distances closer than 50 feet from the center of the lane of travel may be made. In such a case, the measuring device shall be so calibrated as to provide for measurements equivalent to the noise limit established by this section measured at 50 feet.
(c) Trucks. A truck, truck tractor, or bus that is not equipped with an identification plate or marking bearing the name and gross vehicle weight rating of the manufacturer shall be considered as having a gross vehicle weight rating of 6,000 pounds or more if the unladen weight is more than 5,000 pounds.

§ 4523 Exhaust systems, mufflers and noise control. 

(a)  Compliance with established sound levels. --Every motor vehicle operated on a highway shall be constructed, equipped, maintained and operated so as not to exceed the sound level for the vehicle as prescribed in regulations promulgated by the department. The test procedures and instrumentation to be utilized shall also be established by regulation.
(b)  Compliance with exhaust requirements. --In addition to any requirements established under sections 4531 (relating to emission control systems) and 4532 (relating to smoke control for diesel-powered motor vehicles), every motor vehicle shall be constructed, equipped, maintained and operated so as to prevent engine exhaust gases from penetrating and collecting in any part of the vehicle occupied by the driver or passengers.
(c)  Mufflers and related equipment. --Every motor vehicle shall be equipped with a muffler or other effective noise suppressing system in good working order and in constant operation and no muffler or exhaust system shall be equipped with a cutout, bypass or similar device.
(d)  Unauthorized modification of equipment. --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 the vehicle above the maximum levels permitted under subsection (a) or violate the provisions of subsection (b). Headers and side exhausts are permitted provided the vehicle meets all the requirements of this section.
(e)  Fire equipment and racing vehicles. --This section does not apply to fire equipment or to racing vehicles being operated in an organized racing or competitive event conducted under a permit issued by local authorities.

Rhode Island General Laws

§ 31-23-13. Muffler 

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 annoying smoke. No person shall use a muffler cutout, bypass, or similar device upon a motor vehicle on a highway. Any exhaust system shall be deemed defective if any changes, modifications, alterations, deletions, or adjustments have been made which would cause the exhaust system to generate a higher or louder sound level than would be generated by the exhaust system customarily installed by the manufacturer as original equipment. The defective exhaust system shall be replaced or repaired to restore the exhaust system to the performance specifications of the original equipment. Failure to replace or restore the exhaust system as required in this section within five (5) days shall be deemed a civil violation and violators are subject to fines enumerated in § 31-41.1-4.

§ 31-45-1. Noise limits

(a) No person shall operate a motor vehicle, nor shall the owner of any vehicle allow the vehicle to be operated, at any time, or under any condition of grade, load, acceleration, or deceleration, in such a manner as to exceed the following noise limit based on a distance of fifty feet (50′) from the center of the lane of travel within the speed limit. For the purposes of this section, "dbA" means decibels measured with a calibrated sound level meter weighted to the "A" scale.
(b) In speed zones of thirty-five miles per hour (35 mph) or less, not more than eighty-six (86) dbA. In speed zones of more than thirty-five miles per hour (35 mph), not more than ninety (90) dbA.

(c) Violations of this section are subject to fines enumerated in § 31-41.1-4.

South Carolina Code of Laws

§ 56-5-5020. Mufflers.

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 annoying smoke and no person shall use a muffler cutout, bypass or similar device upon a motor vehicle upon a highway. The engine and power mechanism of every motor vehicle shall be so equipped and adjusted as to prevent the escape of excessive fumes and smoke. 

South Dakota Codified Laws

§ 32-15-17.  Exhaust system and muffler requirements -- Class 2 misdemeanor 

No person may drive a motor vehicle on a highway unless the motor vehicle is equipped with an exhaust system and a muffler both in good working condition and in constant operation to prevent excessive or unusual noise.

Exhaust systems on passenger or passenger-carrying vehicles used on any highway shall discharge the exhaust fumes at a location to the rear of the vehicle body or direct the exhaust fumes outward from the side of the vehicle body at a location rearward of any operable side windows. Any motor vehicle equipped with side exhaust according to the original vehicle manufacturer specifications is exempt from the location requirements. A bus used for the purpose of carrying school children may discharge the exhaust on the left side in front of the rear axle.

Exhaust systems on property-carrying vehicles used on any highway shall discharge the exhaust fumes at a point rearward of the passenger-carrying compartment.

No person may use a muffler cut-out on any motor vehicle upon a highway.

A violation of this section is a Class 2 misdemeanor.

Tennessee Code

§ 55-9-202 Mufflers -- Muffler cutouts prohibited -- Penalty.

SECTION 1. (a) It is unlawful for a person to drive a motor vehicle on a road, street, or highway if the motor vehicle is not equipped with a muffler in good working order and in constant operation. A motor vehicle's muffler is deemed to be not in good working order or in constant operation if the motor vehicle produces excessive or unusual noise or annoying smoke.

(b)  It is unlawful to use a "muffler cutout" on any motor vehicle upon any road, street or highway.

(c)  A violation of this section is a Class C misdemeanor.
 

SECTION 2. This act takes effect July 1, 2023, the public welfare requiring it.

Texas Code

§ 547.604.  Muffler Required 

(a) A motor vehicle shall be equipped with a muffler in good working condition that continually operates to prevent excessive or unusual noise.

(b) A person may not use a muffler cutout, bypass, or similar device on a motor vehicle.

Utah Code

§ 41-6a-1626.  Mufflers -- Prevention of noise, smoke, and fumes -- Air pollution control devices 

(1) (a) A vehicle shall be equipped, maintained, and operated to prevent excessive or unusual noise.
(b) A motor vehicle shall be equipped with a muffler or other effective noise suppressing system in good working order and in constant operation.
(c) A person may not use a muffler cut-out, bypass, or similar device on a vehicle.

23 Vermont Statues

§ 1221. Condition of vehicle

A motor vehicle, operated on any highway, shall be in good mechanical condition and shall be properly equipped.

Virginia Code

§ 46.2-1047. Muffler cutout, etc., illegal
 
It shall be unlawful to sell or offer for sale any (i) muffler without interior baffle plates or other effective muffling device or (ii) gutted muffler, muffler cutout, or straight exhaust. It shall be unlawful for any person to operate on the highways in the Commonwealth a motor vehicle, moped, or motorized skateboard or foot-scooter equipped with a gutted muffler, muffler cutout, or straight exhaust.

§ 46.2-1049.  Exhaust system in good working order 

No person shall drive and no owner of a vehicle shall permit or allow the operation of any such vehicle on a highway unless it is equipped with an exhaust system in good working order and in constant operation to prevent excessive or unusual levels of noise; provided however, that for motor vehicles, such exhaust system shall be of a type installed as standard factory equipment, or comparable to that designed for use on the particular vehicle as standard factory equipment. An exhaust system shall not be deemed to prevent excessive or unusual noise if it permits the escape of noise in excess of that permitted by the standard factory equipment exhaust system of private passenger motor vehicles or trucks of standard make.

The term "exhaust system," as used in this section, means all the parts of a vehicle through which the exhaust passes after leaving the engine block, including mufflers and other sound dissipative devices.

Chambered pipes are not an effective muffling device to prevent excessive or unusual noise, and any vehicle equipped with chambered pipes shall be deemed in violation of this section.

The provisions of this section shall not apply to (i) any antique motor vehicle licensed pursuant to § 46.2-730, provided that the engine is comparable to that designed as standard factory equipment for use on that particular vehicle, and the exhaust system is in good working order, or (ii) converted electric vehicles. 

Washington Administrative Code 

§ 173-62-030. Standards.

(1) No person shall operate any motor vehicle or any combination of such vehicles upon any public highway under any conditions of grade, load, acceleration or deceleration in such a manner as to exceed the maximum permissible sound levels for the category of vehicle in Table I, as measured at a distance of 50 feet (15.2 meters) from the center of the lane of travel within the speed limits specified, under procedures established by the state commission on equipment in chapter 204-56 WAC, 'procedures for measuring motor vehicle sound levels.'

Table I
IN-USE MOTOR VEHICLE NOISE PERFORMANCE STANDARDS
Measured @ 50 feet (15.2 meters)
Vehicle Category (type):
Automobiles, light trucks and all other motor vehicles 10,000 pounds GVWR or less: 45 mph or less – 72 dBA. Over 45 mph – 78 dBA.

(2) Every motor vehicle operated upon the public highways shall at all times be equipped with an exhaust system and a muffler in good working order and constant operation to prevent excessive or unusual noise.
(3) No person shall operate a motor vehicle in such a manner as to cause or allow to be emitted squealing, screeching or other such noise from the tires in contact with the ground because of rapid acceleration or excessive speed around corners or other such reason, except that noise resulting from emergency braking to avoid imminent danger shall be exempt from this provision.
(4) No person shall operate any motor vehicle upon any public highway if the vehicle exhaust system exceeds the maximum permissible sound levels of Table II for the category and year of vehicle, as measured at a distance of twenty inches (0.5 meter) from the exhaust outlet under procedures established by the state commission on equipment in chapter 204-56 WAC, 'procedures for measuring motor vehicle sound levels.'

Table II
IN-USE MOTOR VEHICLE EXHAUST SYSTEM NOISE PERFORMANCE STANDARDS
Measured @ 20 inches (0.5 meters)
Vehicle Category (type)
Automobiles, light trucks and all other motor vehicles 10,000 pounds GVWR or less: Before 1986 – 95 dBA. 1986 and after – see above.

173-62-060. Enforcement.

 
(1) Measurements shall be made with a sound level meter meeting Type 1, S1A, 2 or S2A requirements as specified in the American National Standards Specifications for Sound Level Meters S1.4-1971 as required under measurement procedures established in chapter 204-56 WAC, 'procedures for measuring motor vehicle sound levels.'
(2) Violation of any in-use motor vehicle noise standard set forth in this chapter shall be a traffic infraction, enforced by such authorities and in such manner as violations of chapter 46.37 RCW.
(3) Law enforcement personnel selected to measure vehicle sound levels shall have received training in the techniques of sound measurement and the operation of sound measuring instruments.
(4) Any enforcement officer who by use of the initial inspection procedures of chapter 204-56 WAC suspects that a motor vehicle may be in violation of the standards of this chapter may require the operator to have the vehicle presented for sound level measurement. Measurements of a motor vehicle may be performed at off-road sites to determine compliance with the in-use standards.
(5) Any operator who fails to comply with the directive to present the vehicle to a sound level measurement test shall be in violation of this chapter.

§ 46.37.390. Mufflers required -- Smoke and air contaminant standards -- Definitions -- Penalty, exception 

(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.
(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. 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.

D.C. Mun. Regs. Tit. 20

§ 2812 ALTERATION OF MOTOR VEHICLE EXHAUST SYSTEM

2812.1 No person shall modify or alter the exhaust system of a motor vehicle or motorcycle in a manner that will amplify or increase the noise emitted by the vehicle above the level permitted under § 2811 of this chapter.
2812.2 No person shall use or operate a motor vehicle or a motorcycle having an exhaust system that has been modified or altered in a manner that will amplify or increase the noise emitted by the vehicle above the level permitted under § 2811 of this chapter.

§ 2811 OPERATIONAL LIMITS FOR MOTOR VEHICLES
2811.1 No person shall operate a motorcycle, motor vehicle, or combination of motor vehicles of a type subject to registration under D.C. Code § 40-103 (1990 Repl. Vol.) at any time, or under any condition of grade, load, acceleration, or deceleration in a manner that exceeds the maximum noise limits designated in the table of this subsection for the specified speed limits, measured at a distance of fifty feet (50 ft.) from the center line of travel by a sound level meter switched to the A-weighting network, in accordance with such nationally recognized test procedures as the administering agency may prescribe in accordance with § § 2700.7 through 2700.9 of Chapter 27 of this subtitle.

(a)Any motor vehicle with a manufacturer's gross vehicle weight rating of ten thousand pounds (10,000 lbs.) or more, and any combination of vehicles towed by that motor vehicle: 35 MPH or less: 86 dB(A) Over 35 MPH: 90 dB(A) Stationary Run-up: 88 dB(a)

Washington, D.C. DMV:
No historic motor vehicle shall be required to comply with any performance standard with which it was not legally required to achieve or comply when it was manufactured. Performance standards shall include, but not be limited to, standards or requirements for exhaust and noise emissions and for fuel usage.

West Virginia Code

§ 17C-15-34.  Mufflers; prevention of noise, fumes and smoke.

(a) 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. Such muffler shall be the muffler originally installed by the manufacturer of the vehicle or, if a replacement, the equivalent thereof. No person shall use a muffler cutout, bypass, or similar device upon a motor vehicle on a highway.

(b) The engine and power mechanism of every motor vehicle shall be so equipped and adjusted as to prevent the escape of excessive fumes or smoke.

Wisconsin

§ 347.39. Mufflers.

(1) No person shall operate on a highway any motor vehicle subject to registration unless such motor vehicle is equipped with an adequate muffler in constant operation and properly maintained to prevent any excessive or unusual noise or annoying smoke. This subsection also applies to motor bicycles.

(2) No muffler or exhaust system on any vehicle mentioned in sub. (1) shall be equipped with a cutout, bypass or similar device nor shall there be installed in the exhaust system of any such vehicle any device to ignite exhaust gases so as to produce flame within or without the exhaust system. No person shall modify the exhaust system of any such 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 the requirements of this section.

(3) In this section, "muffler" means a device consisting of a series of chambers of baffle plates or other mechanical design for receiving exhaust gases from an internal combustion engine and which is effective in reducing noise.

Wyoming Statutes

§ 31-5-953.  Mufflers.

(a) Every vehicle shall be equipped, maintained and operated so as to prevent excessive or unusual noise. Every motor vehicle shall at all times be equipped with a muffler or other effective noise suppressing system in good working order and in constant operation. No person shall use a muffler cut-out, bypass or similar device.

(b) The engine and power mechanism of every motor vehicle shall be so equipped and adjusted as to prevent the escape of excessive fumes or smoke.

(c) This section applies to motorcycles, motor-driven cycles, multipurpose vehicles and mopeds.