§ 24-368. Unnecessary noise; decibel rating.

(a)

Definitions. For the purposes of this section, certain words and phrases used herein are defined as follows:

A-weighted level means the total sound pressure level of all noise as measured with a sound level meter using the A-weighing network. The unit of measurement is the dB(A).

Ambient noise means the all-encompassing noise associated with a given environment being usually a composite of sounds from many sources, near and far.

Band pressure level means the sound for a specified frequency band which is the sound pressure level for the sound contained within the restricted band. The reference pressure shall be specified.

Cycle means the complete sequence of values of a periodic quantity that occurs during a specified period.

Decibel or dB means one-tenth of a bel and is a unit of level when base of the logarithm is the tenth root of ten, and the ties concerned are proportional to power.

Sound analyzer means a device for measuring the band pressure level or pressure spectrum level of a sound as a function of frequency.

Sound level meter means an instrument, including a microphone, an amplifier, an output meter, and frequency-weighting networks for the measurement of noise and sound levels in a specified manner.

Sound pressure level means, in decibels of sound, a level that is 20 times the logarithm to the base ten of the ratio of the pressure of this sound to the reference pressure, which reference pressure is for the purposes of this section a reference pressure of 20 micronewtons per meter squared. All technical definitions are in accordance with American National Standards Institute S1. 1-1960 entitled, "Acoustical Terminology."

(b)

Motorized vehicles. It shall be unlawful to operate, or permit the operation of, a motorized vehicle, including, but not limited to, cars, trucks, buses, motorcycles, motorbikes, minibikes, and go-carts, within the county, on private or public property, which creates a noise or sound which exceeds the noise level limits set out in Table I:

TABLE I. LIMITING NOISE LEVELS
FOR MOTOR VEHICLES

Maximum Allowable
Limit (db(A))

 

Trucks and buses over 10,000 pounds:

Measured at 50 feet ..... 87

Measured at 25 feet ..... 93

Trucks and buses under 10,000 pounds:

Measured at 50 feet ..... 80

Measured at 25 feet ..... 86

Passenger cars:

Measured at 50 feet ..... 78

Measured at 25 feet ..... 84

Motorcycles, go-carts, trail bikes and other motorized vehicles not classified as trucks or passenger cars:

Measured at 50 feet ..... 87

Measured at 25 feet ..... 93

(1)

The measurement of sound or noise shall be made with a sound level meter meeting the standards prescribed by the American National Standards Institute. The instrument shall be maintained in calibration and good working order. A calibration check shall be made of the system at the time of any noise measurement. Measurements recorded shall be taken so as to provide a proper representation of the noise source and shall not exceed the above levels as measured in any direction. The microphone during measurement shall be positioned so as not to create any unnatural enhancement or diminution of the measured noise. A windscreen for the microphone shall be used when required. Traffic, aircraft and other transportation noise sources and other background noises shall not be considered in taking measurements except where such background noise interferes with the primary noise being measured.

(2)

Measurement of noise levels caused by a moving vehicle shall be confirmed by a noise level measurement taken with the vehicle stationary. The driver of said vehicle shall be required to accelerate his engine to one-half throttle, in order to conduct the noise level reading.

(c)

Mufflers. It shall be unlawful for any person to operate or cause to be operated any muffler attached to any motor vehicle or any other mechanized unit which produces noise levels exceeding dB(A) ratings as set out in Table I and accompanying subsections (b)(1) and (2) of this section.

(d)

Horns and other warning devices generally. It shall be unlawful for any person to operate or cause to be operated any horn, siren, whistle, bell or any electronic blast which may be attached to any motor vehicle or other mechanized unit which is in any manner inconsistent with section 24-355.

(e)

Trains. It shall be unlawful for any person to operate or cause to be operated a warning device of any type, including, but not limited to, a whistle, horn or electronic blast, on trains or vehicles which operate on stationary rails in excess of 87 dB(A) at 50 feet for a sustained period of more than 30 seconds, except as may be required by any federal safety regulation requiring sounding of warning signals at grade crossings.

(f)

Manner of enforcement. Violations of this section shall be prosecuted in the same manner as other violations of this article, and shall be initiated upon issuance of a traffic citation ticket, or brought upon complaint of a private citizen by issuance of a summons, after verification by an officer using a sound meter.

(g)

Exemptions. The following uses and activities shall be exempt from noise level regulations:

(1)

Ambulances, whether owned by private company or government operated, while upon call to scene of accident or emergency situation.

(2)

Vehicles used as garbage collection trucks while in performance of duties and used for either loading or processing of garbage and debris, whether privately owned or government operated.

(3)

County fire equipment upon emergency call and return.

(4)

Sheriff and police equipment, and/or other city, county, state and federal law enforcement equipment, upon emergency call.

(5)

Vehicular equipment used in connection with removal of trees, brush, undergrowth, etc., whether privately owned or government operated.

(6)

All of the vehicles cited in subsections (g)(1) through (5) of this section, with the exception of county fire equipment, shall be required to maintain mufflers and related equipment within the noise level regulations contained in this section.

(Code 1992, § 20-157; Ord. No. 90, § 1, 8-5-1991)

State law reference

Excessive noise from motor vehicles, T.C.A. § 55-8-193.