(A) Sound from a vehicle operating on a public road or highway shall be measured at a distance
of 25 feet or greater from the center of the lane of travel.
Vehicle Sound Test Procedure:
Noise sound levels shall be measured at a height of at least 4 feet above the immediate surrounding surface and at least 8 feet away from reflective surfaces; which include any person, building, tree trunk, vehicle or any other obstruction other than the person making the measurement. The sound level shall be recorded, along with the description of the vehicle that is the source of the dominant noise, the vehicle’s approximate location, the location of the measurement, the approximate time of the measurement, sufficient information to identify the instrument used and its settings, calibrations, weather, wind speed, ambient sound level, and the name of the person taking the measurement.
(B) Sound from a vehicle operating on private property or public property which is not a road or highway, shall be measured 25 feet from the dwelling nearest the sound source at issue.
Vehicle Sound Test Procedure:
Noise sound levels shall be measured at a height of at least 4 feet above the immediate surrounding surface and at least 8 feet away from reflective surfaces; which include any person, building, tree trunk, vehicle or any other obstruction other than the person making the measurement. The sound level shall be recorded, along with the description of the vehicle that is the source of the dominant noise, the vehicle’s approximate location, the location of the measurement, the approximate time of the measurement, sufficient information to identify the instrument used and its settings, calibrations, weather, wind speed, ambient sound level, and the name of the person taking the measurement.
(C) Sound from a non-vehicular source shall be measured 25 feet beyond the property line from which the sound originates, or if that is not physically possible or practical, measurement may be taken in the right-of-way of any public street or highway.
Non-Vehicular Sound Test Procedure:
Noise sound levels shall be measured at a height of at least 4 feet above the immediate surrounding surface and at least 8 feet away from reflective surfaces; which include any person, building, tree trunk, vehicle or any other obstruction other than the person making the measurement. The sound level shall be recorded, along with the description of the source of the dominant noise, the source’s approximate location, the location of the measurement, the approximate time of the measurement, sufficient information to identify the instrument used and its settings, weather, wind speed, ambient sound level, and the name of the person taking the measurement, name of complainant, if known.
(D) Sound from a parked, non-moving vehicle for a roadside static or stationary noise level test shall be measured in accordance with the following methods and standards:
(1) Test site. The test site should be an open surface free of large reflecting surfaces, (other than the ground), parked vehicles, signboards, buildings, large rocks or hillsides located within a 8-foot radius of the vehicle being tested and the location of the microphone of the sound level meter.
(2) Ambient conditions. The ambient conditions shall be observed during measurements:
(a) Wind speed. Sound level measurements shall not be made when wind speed is in excess of:
1. Twenty mph for the close static or stationary noise level tests; or
2. Twelve mph for all other tests.
(b) Precipitation. Sound level measurements shall not be made when precipitation is falling in such a manner to affect the equipment or the measurement readings.
(c) Background sound level. The ambient sound level, including wind effects, at the test site due to sources other than the sound source being measured, shall be at least 10 dB(A) lower than the sound produced by the vehicle under test.
(3) Battery check. A battery check shall be conducted on all instruments before calibration and measurement.
(4) Wind speed check. An anemometer shall be used to check wind speed for determining ambient conditions prior to sound level measurements.
(5) Sound meter. Calibration of the sound level meter using an acoustically coupled sound level calibrator with an accuracy of +/- 0.5 dB shall be made immediately before the first test of the day; and prior to the test and after the test. Field calibration should be made at intervals not exceeding 2 hours when the instrument is to be used for more than a 2-hour period. A type 1 or type 2 sound level meter shall be used. The sound level meter shall be returned once per year to the manufacturer or to a qualified laboratory, to be calibrated to standards traceable to the ANSI S1.4-1983 standards. The sound meter shall be set for the A-weighting scale and shall be set for slow dynamic response.
(6) Tachometer. (For set or swept RPM tests) The tachometer shall be either of 1 of 2 types: electric or vibrating reed. The electric tachometer shall be an inductive type pickup type of easy attachment to any spark plug, containing its own external power supply. The vibrating reed tachometer shall be designed for use on any internal combustion engine. All tachometers shall be calibrated once per year in accordance with the manufacturer specifications.
(7) Sound level measurements.
(a) While making sound level measurements, not more than 1 person other than the operator, the measurer, and the assistant, if necessary, shall be within 8 feet of the vehicle under test or the microphone of the sound level meter and that person shall be directly behind the measurer on a line through the microphone and the sound level meter and the measurer. For 2-wheeled vehicles, the operator may sit astride of the vehicle, in a normal riding position with both feet on the ground. If that is not possible because of the seat height of the vehicle, an assistant may hold the vehicle by the forks, front wheel or handlebars so that it is stationary with its longitudinal plane of symmetry vertical.
(b) The engine of the vehicle being tested shall be at normal operating temperature during the test. Tests shall be made on each side of the vehicle having an exhaust outlet. The microphone of the sound level meter shall be located 20 inches, +/- ½ inch, behind the exhaust outlet. If there is more than 1 exhaust outlet per side, the microphone of the sound level meter shall be located with reference to the rear most outlet. The microphone of the sound level meter shall be at the same height as the center of the exhaust outlet if possible, but no closer to any surface than 8 inches. The microphone of the sound level meter shall be at a 45 degree angle, +/- 10 degrees, to the normal travel line of the vehicle. The longitudinal axis of the sound level meter shall be in a plane parallel to the ground plane. No wire or rigid means of distance measurement shall be attached to the sound level measuring system. A windscreen of open cell foam, or other acoustically invisible material as shall be provided by the manufacturer, shall be placed over the microphone to protect it from moisture, exhaust gases and wind effects.
(8) Automotive and diesel test.
(a) Automobile and diesel engine test RPM.
1. Automobiles and trucks. The sound level measurement shall be made with the engine speed stabilized at 2,500 RPM.
2. Diesel engine vehicles. The sound level measurements shall be made at the vehicle’s maximum governed no-load speed. If the engine is not provided with a governor, the vehicle shall be operated at 2,500 RPM.
(b) Automobile and diesel engine test IDLE. The engine of the vehicle under test shall be at normal operating temperature. The engine shall be run at idle speed. If the engine will not run without stalling, the throttle shall be opened the minimum amount required to keep the engine running. The engine shall be run at idle speed for at least 5 seconds.
(c) Motorcycle test IDLE and RPM.
1. Idle test. The engine of the motorcycle under test shall be at normal operating temperature. The engine shall be run at idle speed. If the engine will not run without stalling, the throttle shall be opened the minimum amount required to keep the engine running. The engine shall be run at idle speed for at least 5 seconds.
2. Set RPM test. The sound level measurement shall be made with the engine speed stabilized at 1 of the following values:
a. For less than 3 cylinders or more than 4 cylinders test motorcycle at 2,000 RPM (+/- 200 RPM) or 75% of maximum engine speed whichever is less; or
b. For 3 cylinders or 4 cylinders test motorcycle at 5,000 RPM (+/- 200 RPM) or 75% of maximum engine speed whichever is less.
(d) Sound level. The recorded sound level shall be the highest value obtained at the appropriate, constant engine speed and shall exclude peaks due to unrelated ambient noise, engine noise or extraneous impulsive-type noise. At least 2 measurements shall be made.
(9) Test recording. The sound level shall be recorded, along with the description of the vehicle being the source of the noise, the location of the measurement, the approximate time of the measurement, sufficient information to identify the various instruments used and their settings, calibration, battery check, weather, wind speed, ambient background sound level, results of the sound level test, and the name of the person, along with any assistant(s) taking the measurement.
(2002 Code, Ch. 84, § 84.04) (Ord. passed 6-23-2003; Am. Ord. passed 4-20-2004; Am. Ord. passed 7-19-2011)