AHRA: American Hot Rod Association or its successor body.
“Ambient”: the all-encompassing sound associated with a given environment without the noise source of interest.
“Angle of incidence”: the orientation of the microphone relative to the sound source.
ANSI: American National Standards Institute or its successor bodies.
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Antique vehicle: a motor vehicle that is more than 25 years of age or a bona fide replica thereof and which is driven on the highways only going to and returning from an antique auto show or an exhibition, or for servicing or demonstration, or a fire-fighting vehicle more than 20 years old which is not used as fire-fighting equipment but is used only for the purpose of exhibition or demonstration.
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Background Sound Level: the A-weighted sound level, measured in accordance with the procedures specified in Section 900.103, which is exceeded 90 percent of the time during the period of observation, sounds from the sound source are inaudible. The period of observation need not necessarily be contiguous; however, the period of observation must be at least of 10 minutes duration.
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C-weighted Sound Level: in decibels, a frequency weighted sound pressure level, determined by the use of the metering characteristics and C-weighted network specified in ANSI document §1.4-1971 S1.4-1983 (R2001. 1976) " American National Standard Specification for Sound Level Meters.", incorporated by reference at Section 900.106.
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"Construction: on-site erection, fabrication, installation, alteration, demolition or removal of any structure, facility, or addition thereto, including all related activities including, but not restricted to, clearing of land, earth-moving, blasting and landscaping.
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Daytime hours: 7:00 am to 10:00 pm, local time.
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dB(A): A-weighted Sound Level in decibels."
Dealer: every person engaged in the business of selling vehicles to persons who purchase such vehicles for purposes other than resale, and who has an established place of business for such activity in this state.
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Decibel (dB): a unit of measure, on a logarithmic scale to the base 10, of the ratio of the magnitude of a particular sound pressure to a standard reference pressure, which, for purposes of this Chapter, shall be 20 micronewtons per square meter (uN/m2).
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Drag racing: any acceleration contest between two racing vehicles racing from a standing start over a precisely measured, straight line course.
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Drag racing facility: any motor racing facility upon which is conducted drag racing.
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Drag racing vehicle: any racing vehicle which is participating in a drag race at a drag racing facility.
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Exhaust system: the system comprised of a combination of components which provides for the enclosed flow of exhaust gas from engine parts to the atmosphere.
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Existing motor racing facility: any motor racing facility, the construction of which commenced prior to August 10, 1973.
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Existing property-line- noise-source: any property-line-noise-source, the construction or establishment of which commenced prior to August 10, 1973. For the purposes of this sub-section, any property-line-noise-source whose A, B or C land use classification changes, on or after August 10, 1973, is be considered an existing property-line-noise-source.
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Farm tractor: every motor vehicle designed and used primarily as a farm implement for drawing wagons, plows, mowing machines and other implements of husbandry, and every implement of husbandry which is self-propelled.
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Fast Dynamic Characteristic: the dynamic characteristic specified as fast in ANSI §S1.4-198371 (R2001. 1976) " American National Standard Specification for Sound Level Meters", incorporated by reference at Section 900.106 and the latest revision thereof.
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Fast meter response: as specified in ANSI §1.4-1971, S1.4–1983 (R2001) “American National Standard Specification for Sound Level Meters”, incorporated by reference at Section 900.106 or subsequent revisions.
“Fluctuating sound”: a class of nonsteady sound where sound pressure level varies over a range greater than 6 decibels (dB) with the “slow” meter characteristic, and where the meter indication does not equal the ambient level more than once during the period of observation.
Frequency-weighted sound pressure: root mean square of the instantaneous sound pressure which is frequency-weighted (i.e. filtered) with a standard frequency characteristic (e.g., A or C) and exponentially time-weighted in accordance with the standardized characteristics slow (S), fast (F), impulse (I) or peak, with both weightings specified in accordance with ANSI S1.4–1983 (R2001) “American National Standard Specification for Sound Level Meters”, incorporated by reference at Section 900.106. The frequency weighting used shall be specified explicitly (e.g., A, C or octave band).. The unit frequency weighted sound pressure is the pascal (Pa).
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Gross Vehicle Weight (GVW): the maximum loaded weight for which a motor vehicle is registered or, for vehicles not so registered, the value specified by the manufacturer as the loaded weight of the vehicle.
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Highway: the entire width between the boundary lines of every way publicly maintained when any part thereof is open to the use of the public for purposes of vehicular travel.
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“Intermittent sound”: a class of nonsteady sound where the meter indicates a sound pressure level equal to the ambient level two or more times during the period of observation. The period of time during which the level of the sound remains at a value different from that of the ambient is of the order of one second or more.
Leq: equivalent continuous sound pressure in decibles: ten times the logarithm to the base ten of the ratio of a time mean square sound pressure to the square of reference sound pressure. The reference pressure is 20 micronewtons per-square meter level or equivalent continuous frequency-weighted sound pressure level. .
Leq (A): A-weighted time-average (equivalent-continuous) sound level.
Leq (octave band-Hz): time-average (equivalent-continuous) sound level in the octave band specified by its center frequency e.g. Leg (125-Hz).
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Midget racing vehicle: a front engine, single seat, openwheel racing car smaller and of lesser engine displacement then standard cars of the type.
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Motor racing facility: any facility or course upon which is conducted motor racing activities or events.
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Motor driven cycle: every motorcycle, motor scooter, or bicycle with motor attached, with less than 150 cubic centimeter piston displacement.
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Motorcycle: every motor vehicle having a seat or saddle for the use of the rider and designed to travel on not more than 3 wheels in contact with the ground, but excluding a tractor.
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Motorcycle racing facility: any motor racing facility upon which is conducted motorcycle racing, except oval racing facilities or drag racing facilities.
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Muffler: a device for abating the sounds of escaping gases of an internal combustion engine.
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NHRA: National Hot Rod Association or its successor body.
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New motor racing facility: any motor racing facility, the construction of which commenced on or after August 10, 1973.
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New snowmobile: a snowmobile, the equitable or legal title to which has never passed to a person who purchases it for purposes other than resale.
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Nighttime hours: 10:00 pm to 7:00 am, local time.
“Noise floor”: the electrical noise (in decibles) of the sound measurement system. When the noise floor is determined by placing a calibrator over the microphone of the sound measurement system, the noise floor may include acoustic noise due to leakage around the calibrator.
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Noise pollution: the emission of sound that unreasonably interferes with the enjoyment of life or with any lawful business or activity.
“Nonsteady sound”: a sound whose sound pressure level shifts significantly during the period of observation. Meter variations are greater than +- 3 dB using the “slow” meter characteristic.
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Octave band sound pressure level: the sound pressure level for the sound being measured contained within the specified octave band. The reference pressure is 20 micronewtons per square meter.
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Oval racing: any contest between two or more racing vehicles on a closed or oval racing surface.
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Oval racing facility: any motor racing facility, upon which is conducted oval racing.
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Oval racing vehicle: any racing vehicle which is participating in an oval race at an oval racing facility.
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Pascal (Pa): a unit of pressure. One pascal is equal to one newton per square meter.
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Passenger car: a motor vehicle designed for the carrying of not more than ten persons, including a multi-purpose passenger vehicle, except any motor vehicle of the second division as defined in Ill. Rev. Stat. 1981, ch. 95-1/2, par. 1-146, and except any motorcycle or motor driven cycle. t+1
“Period of observation”: the time interval during which acoustical data are obtained. The period of observation is determined by the characteristics of the noise being measured and must be at least ten times as long as the response time of the instrumentation. The greater the variation in indicated sound level, the longer must be the observation time for a given expected precision of the measurement.
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Person: any individual, corporation, partnership, firm, association, trust, estate, public or private institution, group, agency, political subdivision of this State, any other State or political subdivision or agency thereof or any legal successor, representative, agent or agency of the foregoing.
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Preferred frequencies: those frequencies in Hertz preferred for acoustical measurements which, for the purposes of this Chapter, consist of the following set of values: 20, 25, 31.5, 40, 50, 63, 80, 100, 125, 160, 200, 250, 315, 400, 500, 630, 800, 1000, 1250, 1600, 2000, 2500, 3150, 4000, 5000, 6300, 8000, 10,000, 12,500.
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Prominent discrete tone: sound, having a one-third octave band sound pressure level which, when measured in a one-third octave band at the preferred frequencies, exceeds the arithmetic average of the sound pressure levels of the two adjacent one-third octave bands on either side of such one-third octave band by:
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Property-line-noise-source: any equipment or facility, or combination thereof, which operates within any land used as specified by 35 Ill. Adm. Code 901.101. Such equipment or facility, or combination thereof, must be capable of emitting sound beyond the property line of the land on which operated.
“Quasi-steady sound”: a train of two or more acoustical impulses. Examples of quasi-steady sound are that from riveting and pneumatic hammer.
Racing vehicle: every self-propelled device, in, upon or by which any person may be transported and which is participating in a motor racing activity or event at a motor racing facility.
“Reflective surface”: any building, hillside, or similar object (other than the flat ground surface) that reflects sufficient sound to affect the sound pressure level readings obtained from a noise source. Not included as reflective surfaces are small objects such as trees, posts, chain-linked fences, fire hydrants, vegetation such as bushes and shrubs, or any similar object.
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Registered: a vehicle is registered when a current registration certificate or certificates and registration plates have been issued for it under the laws of any state pertaining to the registration of vehicles.
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Residential dwelling unit: all land used as specified by Standard Land Use Coding Manual (SLUCM) Codes 110 through 190 and those portions of land used as specified by SLUCM Code 6741 used for sleeping.
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SAE: Society of Automotive Engineers.
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Slow Dynamic Characteristic: the dynamic characteristic specified as "Slow" in ANSI document §1.4-1971 (R. 1976) S1.4–1983 (R2001) " American National Standard Specification for Sound Level Meters.", incorporated by reference at Section 900.106.
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SLUCM: the Standard Land Use Coding Manual which designates land activities by means of numerical codes.
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Snowmobile: a self-propelled device designed for travel on snow or ice or natural terrain steered by skis or runners, and supported in part by skis, belts, or cleats.
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Sound: A physical disturbance causing an oscillation in pressure in a medium (e.g., air) that is capable of being detected by the human ear or a sound measuring instrument.
Sound Exposure: time integral of squared, frequency-weighted instantaneous sound pressure over a given time interval. The time period of integration must be specified: when the sound exposure of the background noise is a significant contributor to the total sound exposure; or when the threshold sound level of the instrument (a level below which the instrument does not accumulate contributions to the integral) used is above the level of the background noise; or when such data is needed to identify a source; or when the time period of integration is otherwise useful. The customary unit for sound exposure is pascal-squared second (Pa2-s). .
Sound exposure level (SEL or Let): ten (10) times the logarithm to the base 10 of the ratio of sound exposure to the reference sound exposure (Eo) of 400 micropascal-squared seconds (uPa2-s). For a given measurement time period of T seconds, the sound exposure level (let ) is related to the time-average sound level (Lpt) as follows: Ler = Lpt + log (T/to) where to is the reference duration of 1 second. The time period of intergration (T) must be specified. The frequency weighting used must be specified explicitly (e.g., A, C or octave band. The A-weighted SEL and C-weighted SEL are abbreviated ASEL and CSEL respectively. An octave band SEL is expressed in terms of the center frequency (e.g., SEL at 125-Hz). The unit for sound exposure level is decibel (dB).
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Sound level (weighted sound pressure level): in decibels, a weighted sound pressure level, determined by the use of metering characteristics and frequency weightings specified in ANSI §1.4-1971 "Specification for Sound Level Meters." twenty (20) times the logarithm to the base 10 of the ratio of the frequency weighted (and time-averaged) sound pressure to the reference pressure of 20 micropascal. The frequency weighting used shall be specified explicitly (e.g., A, C or octave band). The unit for sound level is decibel (dB).
Sound pressure: the root mean square of the instantaneous sound pressures during a specified time interval in a stated frequency band. The unit for sound pressure is pascal (Pa).
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Sound pressure level: in decibels, twenty (20) times the logarithm to the base 10 of the ratio of the magnitude of a particular sound pressure to the standard reference sound pressure of 20 micropascal. The standard reference pressure is 20 micronewtons per square meter. ANSI S12.9- 1988 (R1998) “American National Standard Quantities and Procedures for Description and Measurement of Environmental Sound - Part 1”, incorporated by reference at Section 900.106, reserves the term sound pressure level to denote the un-weighted sound pressure. The unit for sound pressure level is decibel (dB).
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Special mobile equipment: every vehicle not designed or used primarily for the transportation of persons or property and only incidentally operated or moved over a highway, including but not limited to: ditch digging apparatus, well-boring apparatus and road construction and maintenance machinery such as asphalt spreaders, bituminous mixers, bucket loaders, tractors other than truck tractors, leveling graders, finishing machines, motor graders, road rollers, scarifiers, earth-moving carryalls and scrapers, power shovels and drag lines, and self-propelled cranes and other earth-moving equipment.
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Special-motor-racing-event: any motor racing event held on two consecutive days or less in which a substantial number of out-of-state motor racing vehicles are competing and which has been designated as such a special-motor-racing-event by the owner or operator of the motor racing facility.
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Sports car: any automobile which meets the requirements and specifications of the General Competition Rules of the Sports Car Club of America, or its successor body, or any other sports car organization.
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Sports car racing: any competitive event involving one or more sports cars.
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Sports car racing facility: any motor racing facility upon which is conducted sports car racing.
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Sports car racing vehicles: any racing vehicle which is participating in a sports car race at a sports car racing facility.
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Sprint racing vehicle: a front-engined open wheel racing car used especially on short dirt tracks.
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Supercharged racing vehicle: a racing vehicle equipped with a blower or compressor for increasing the volume air charge of an internal combustion engine over that which would be drawn in through the pumping action of the pistons.
“Steady sound”: a sound whose sound pressure level remains essentially constant (that is, meter fluctuations are negligibly small) during the period of observation. Meter variations are less than or equal to +- 3 dB suing the “slow” meter characteristic.
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Tactical military vehicle: every vehicle operated by any federal or state military organization and designed for use in field operations, but not including vehicles such as staff cars and personnel carriers designed primarily for normal highway use.
Time-average sound level (or equivalent-continuous sound level or equivalent-continuous frequency-weighted sound pressure level): twenty (20) times the logarithm to the base 10 of the ratio of the time-average (frequency-weighted) sound pressure to the reference pressure of 20 micropascal. The frequency weighting used must be specified explicitly (e.g., A, C or octave band). The unit of time-average sound level is the decibel (dB).
Time-average (frequency-weighted) sound pressure: square root of the quotient of the time integral of frequency-weighted squared instantaneous sound pressures divided by the time period of integration; or the square root of the quotient of the sound exposure, in pacal-squared seconds (Pa2 –s), in a specified time period, divided by the time period of integration in seconds. The frequency weighting used must be specified explicitly (e.g., A, C or octave band). The unit of time-average sound pressure is the pascal (Pa).
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Unregulated safety relief valve: a safety relief valve used and designed to be actuated by high pressure in the pipe or vessel to which it is connected and which is used and designed to prevent explosion or other hazardous reaction from pressure buildup, rather than being used and designed as a process pressure blowdown.
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Used motor vehicle: a motor vehicle that is not a new motor vehicle.
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Vehicle: every device in, upon, or by which any person or property is or may be transported or drawn upon a highway.
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Weekday: any day which occurs during the period of time commencing at 10:00 p.m. Sunday and ending at 10:00 p.m. Friday during any particular week.
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Weekend day: any day which occurs during the period of time commencing at 10:00 p.m. Friday and ending at 10:00 p.m. Sunday during any particular week.
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Well-maintained muffler: any muffler which is free from defects which affect its sound reduction. Such muffler shall be free of visible defects such as holes and other acoustical leaks.
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