As used in this article, the following terms shall have the meaning indicated:
COMBINATION VEHICLE
Any combination of truck, truck tractor, trailer, semitrailer or pole trailer used upon the highways or streets in the transportation of passengers or property.
EXHAUST SYSTEM
The system comprised of a combination of components which provides for enclosed flow of exhaust gas from engine parts to the atmosphere.
FAST METER RESPONSE
The meter ballistics of meter dynamic characteristics as specified by American National Standard S 1.4-1971.
GROSS VEHICLE WEIGHT RATING
The value specified by the manufacturer as the loaded weight of a vehicle.
MAXIMUM NOISE
The noise emitted from a vehicle during that manner of operation which causes the highest dB(A) level possible from that vehicle.
MOPED
A two- or three-wheeled vehicle which is equipped with a motor that does not exceed 50 cubic centimeters piston displacement, produces two brake horsepower or less and cannot propel the vehicle at a speed greater than 30 miles per hour on a level surface. The power drive system shall not require the operator to shift gears.
MUFFLER
A device for abating the sound of escaping gases of an internal combustion engine.
TOTAL NOISE
Noises radiating from a vehicle, but does not include noise emitted from a horn, siren, bell or other similar device of an authorized emergency vehicle.
A. 
A motor vehicle shall not be operated or driven on a highway or street if the motor vehicle produces total noise exceeding one of the following limits at a distance of 50 feet, except as provided in Subsection A(2)(c) and (3)(c) hereof:
(1) 
A motor vehicle with a gross weight or gross vehicle weight rating of 8,500 pounds or more or a combination vehicle with gross weight or gross vehicle weight ratings of 8,500 pounds or more:
(a) 
Ninety dB(A) if the maximum lawful speed on the highway or street is greater than 35 miles per hour;
(b) 
Eighty-six dB(A) if the maximum lawful speed on the highway or street is not more than 35 miles per hour; and
(c) 
Eighty-eight dB(A) under a stationary run-up test.
(2) 
A motorcycle or moped:
(a) 
Eighty-six dB(A) if the maximum lawful speed on the highway or street is greater than 35 miles per hour;
(b) 
Eighty-two dB(A) if the maximum lawful speed on the highway or street is not more than 35 miles per hour; and
(c) 
Ninety-five dB(A) under a stationary run-up test at 75 inches.
(3) 
A motor vehicle or a combination of vehicles towed by a motor vehicle not covered in Subsection A(1) or (2) hereof:
(a) 
Eighty-three dB(A) if the maximum lawful speed on the highway or street is greater than 35 miles per hour;
(b) 
Seventy-six dB(A) if the maximum lawful speed on the highway or street is not more than 35 miles per hour; and
(c) 
Ninety-five dB(A) under a stationary run-up test 20 inches from the end of the tailpipe.
B. 
This section applies to the total sound of a motor vehicle or a combination of vehicles towed by such motor vehicle and shall not be construed as limiting or precluding the enforcement of any other ordinances of the City relating to motor vehicle noise.
C. 
Test procedures under this section shall comply with those established pursuant to MSA 9.2407(5).
A. 
A motor vehicle, including every motorcycle and moped while being operated on a highway, street or other public right-of-way, shall be equipped with an exhaust system in good working order and in constant operation to prevent excessive or unusual noise and shall be equipped to prevent noise in excess of the limits established in this section. Evidence that a motor vehicle was operated at a noise level in excess of the limits in this section shall be prima facie evidence that the motor vehicle was producing excessive noise.
B. 
For purposes of this section, "motor vehicle" does not include "special mobile equipment," as defined in Section 1.032a of the Uniform Traffic Code, as adopted in Chapter 680, Article II of this Code.
No person shall operate a vehicle, including a motorcycle or moped, 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 cut-out, bypass, amplifier or similar device.
No person, acting either for himself or herself or as the agent or employee of another, shall 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 chapter.
No person shall 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 limits established by this chapter or operate a motor vehicle so altered on a street or highway, nor shall any person knowingly install a muffler or exhaust system which, at the time of installation, exceeds the decibel limits of this chapter.
No person shall remove or render inaccurate or inoperative any sound-monitoring instrument or device that is used for the purpose of enforcing the provisions of §§ 451-23 through 451-30.
A. 
A sound level meter shall be used which has the capacity to give measurement of sound using the A-weighted network and measurements recorded in terms of dB(A). The sound level meter shall meet or exceed the requirements for a type 2 sound level meter as specified in American National Standard Specifications for Sound Level Meters (ANSI S 1.1-1971), approved April 2, 1971, issued by the American National Standards Institute.
B. 
Test instrumentation and procedures used for implementation and enforcement of this chapter shall substantially conform to applicable standards and recommended practices established by the Society of Automotive Engineers and the American National Standards Institute for the measurement of motor vehicle sound levels. The rules may provide for measurement at other than the distance specified herein, provided that the decibel limits applied at the other distances are adjusted accordingly.