1、Standard Method of Test for Determining the Influence of Road Surfaces on Traffic Noise Using the Continuous-Flow Traffic Time-Integrated Method (CTIM) AASHTO Designation: TP 99-181Technical Section: 5a, Pavement Measurement Release: Group 1 (April) American Association of State Highway and Transpor
2、tation Officials 444 North Capitol Street N.W., Suite 249 Washington, D.C. 20001 TS-5a TP 99-1 AASHTO Standard Method of Test for Determining the Influence of Road Surfaces on Traffic Noise Using the Continuous-Flow Traffic Time-Integrated Method (CTIM) AASHTO Designation: TP 99-181Technical Section
3、: 5a, Pavement Measurement Release: Group 1 (April) 1. SCOPE 1.1. The Continuous-Flow Traffic Time-Integrated Method (CTIM) describes the procedures for measuring the influence of road surfaces on highway traffic noise at a specific site. It provides a quantitative measure of the sound pressure leve
4、l at locations adjacent to a roadway. Measurements capture the sound from existing traffic for all vehicles on all roadway lanes. Measurements also include propagation effects over the roadway pavement and adjacent terrain to the nearby measurement location. 1.2. CTIM is to be applied on roadways wh
5、ere measuring single-vehicle pass-by events would be difficult due to continuously flowing, relatively dense traffic (sound levels from single vehicles cannot be properly captured due to contamination from sound from other vehicles). 1.3. This standard is intended for use by acoustic professionals.
6、Competency with acoustical measurement, modeling, and analysis techniques is assumed. 1.4. This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety concerns associated with its use. It is the responsibility of the user of t
7、his standard to consult and establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standards: T 360, Measurement of Tire/Pavement Noise Using the On-Board Sound Intensity (OBSI) Method TP 98, Deter
8、mining the Influence of Road Surfaces on Vehicle Noise Using the Statistical Isolated Pass-By (SIP) Method 2.2. ASTM Standard: F2493, Standard Specification for P225/60R16 97S Radial Standard Reference Test Tire 2.3. FHWA Reports: FHWA-PD-96-008, Development of National Reference Energy Mean Emissio
9、n Levels for the FHWA Traffic Noise Model (FHWA TNM), Version 1.0 2018 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-5a TP 99-2 AASHTO FHWA-PD-96-009, FHWA Traffic Noise Model (FHWA TNM): Users Guide, T
10、NM Version 2.5 Addendum, April 2004 FHWA-PD-96-010, FHWA Traffic Noise Model (FHWA TNM), Version 1.0: Technical Manual, 2004, update sheets available from FHWA FHWA-PD-96-046, Measurement of Highway-Related Noise, Section 4: Existing-Noise Measurements in the Vicinity of Highways 2.4. IEC Standards:
11、 IEC 60942: 2003, ElectroacousticsSound Calibrators IEC 61260: 1995, ElectroacousticsOctave-Band and Fractional-Octave-Band Filters IEC 61672-1: 2002, ElectroacousticsSound Level MetersPart 1: Specifications 2.5. ANSI Standards: S1.42: 2001 (R2006), American National Standard Design Response of Weig
12、hting Networks for Acoustical Measurements S12.8: 1998 (R2008), American National Standard Methods for Determination of Insertion Loss of Outdoor Noise Barriers 3. TERMINOLOGY 3.1. Definitions: 3.1.1. analysis time blockthe shortest length time block for which all sound level, traffic, and meteorolo
13、gical data are analyzed. The analysis time block length shall range from 5 to 15 min. The length of the analysis time block should be long enough to minimize variation in sound levels from one analysis time block to the next, but short enough to facilitate the elimination of periods of time where th
14、e measurements were contaminated by nonhighway source noise. (For example, if measuring 15-min analysis time blocks, it would be undesirable to eliminate the entire 15 min because 5 min of the time period had noise contamination from jets flying overhead; in this case, shorter time blocks would mini
15、mize the amount of data lost to contamination.) 3.1.2. control blockthe calculated energy average, Leq, of all modeled analysis time blocks over the first measurement period that meets the data quality criteria specified in this standard. This control block is used for normalization of the remaining
16、 analysis data blocks for all data sets. 3.1.3. data setthe acoustical, traffic, and meteorological data collected over a measurement period during one site visit. 3.1.4. measurement perioda period of time selected to capture enough data to properly represent the site. A minimum of three reporting t
17、ime blocks or data points are required; additional data are desirable. 3.1.5. On-Board Sound Intensity (OBSI) methoda measurement procedure to evaluate the tire/pavement noise component resulting from the interaction of an ASTM F2493 Standard Reference Test Tire (SRTT) on a pavement surface. Sound i
18、ntensity measurements are taken at defined locations near the tire/pavement interface. 3.1.6. powertrain noisethe noise generated from the powertrain, including the vehicle engine, exhaust system, air intake, fans, transmission, differential, and axles. 3.1.7. reporting time blocka time block compri
19、sed of 15-min Leqsound levels for which sound level, traffic, and meteorological data shall be reported. The reporting time block shall be comprised of one or more analysis time blocks. 2018 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication i
20、s a violation of applicable law.TS-5a TP 99-3 AASHTO 3.1.8. sampling periodthe period of time over which data are collected during data acquisition. The sampling period must be shorter than or equal to the analysis time block. 3.1.9. Statistical Isolated Pass-By (SIP) methoda test method for measuri
21、ng the influence of road surfaces on highway traffic noise. The SIP method captures the sound pressure level from isolated vehicles in existing traffic and allows for the comparison of vehicle noise on roadways of varying surfaces and across studies by comparing measured sound levels to a reference
22、noise curve. 3.1.10. tire/pavement noisethe sound generated by the interaction of the tire with the pavement surface as it traverses the pavement. 3.1.11. traffic noisethe overall noise emitted by multiple vehicles running over the road being evaluated. 3.1.12. vehicle categoriesa vehicle category c
23、onsists of vehicles that have certain common features easy to identify in the traffic stream, such as the number of axles and the size. The common features are assumed to correspond to similarities in sound emission when driven under the same operating conditions. The following vehicle categories ar
24、e considered to be sufficient to describe the noise characteristics of road surfaces and are used in this part of the CTIM method: Table 1Vehicle Categories Vehicle Category Number of Axles, Number of Tires, Gross Vehicle Weight (examples) Automobiles 2 axles, 4 tires, and generally 9,900 lb (4,500
25、kg) and 26,400 lb (12,000 kg) Buses 2 or 3 axles (designated for transportation of 9 or more passengers) Motorcycles 2 or 3 tires (with an open-air driver and/or passenger compartment) Notes: The definitions for these vehicle categories are intended for U.S. applications, including the FHWA Traffic
26、Noise Model (FHWA-PD-96-009, FHWA-PD-96-010) and its vehicle noise emission database (FHWA-PD-96-008). The vehicle category definitions can be found in those references as well as the FHWA highway noise measurement manual (FHWA-PD-96-046). Only vehicles that clearly fall within any of the types desc
27、ribed in this Section shall be measured. Where there is any doubt in classifying a vehicle, the measurement for that vehicle shall be discarded from the study. 3.1.13. vehicle noisethe total noise from a vehicle, including a combination of noise generated by the tire/road interaction (tire/pavement
28、noise), air turbulence, and the powertrain. 4. SUMMARY OF TEST METHOD 4.1. A-weighted, time-integrated sound pressure levels, traffic volumes, speeds, and vehicle categories, and meteorological data are measured continuously on the side of a roadway for a period of time that captures enough data to
29、properly represent the site. 4.2. The acoustical, traffic, and meteorological data measurements are repeated at the same site at a later time to determine either: (1) the difference in sound levels before and after the application of a new surface on the highway; or (2) the difference in sound level
30、s as the pavement on a highway ages. For comparison purposes, traffic and site conditions between data sets should be similar; for example, measuring at the same time of day, weekday or weekend, and the same time of year all help to minimize variation. 4.3. To allow for comparisons between data sets
31、, the measured sound levels are normalized for differences due to variations in traffic using the FHWA Traffic Noise Model (TNM) (FHWA-PD-96-009 and FHWA-PD-96-010), or another model. Traffic data are input into the 2018 by the American Association of State Highway and Transportation Officials. All
32、rights reserved. Duplication is a violation of applicable law.TS-5a TP 99-4 AASHTO model to predict the sound levels for the same period of time that the acoustical data were captured and to determine any sound level adjustments necessary to remove traffic variation influences. Note 1This procedure
33、does not currently allow for site-to-site comparison. 4.4. The method is detailed below, and additional CTIM considerations are available in a memorandum to FHWA dated April 20, 2017, “Additional Considerations for AASHTO Standard Methods of Test TP 98 (SIP) and TP 99 (CTIM).” The memorandum is avai
34、lable at: http:/downloads.transportation.org/TP98-TP99/SIP_CTIM_Considerations_Memo.pdf 5. SIGNIFICANCE AND USE 5.1. This CTIM method provides a measure of the influence of road surfaces on traffic noise at a specific site adjacent to a roadway and allows for the comparison of different pavement con
35、ditions at a specific site, either due to changes over time or through the application of a new pavement surface. 5.2. CTIM measurements capture the sound from existing traffic for all vehicles on all roadway lanes and include propagation effects over the roadway pavement and adjacent terrain to the
36、 nearby measurement location. Although it may be possible to compare results across studies through the use of noise modeling to reduce site and traffic differences, the procedure for such comparisons is not included in this standard at this time. 5.3. The CTIM procedure reports broadband A-weighted
37、, time-integrated sound pressure levels. While it is possible to measure one-third octave band levels in conjunction with the broadband levels, methods to analyze the one-third octave band data are not included in this procedure. 5.4. CTIM should be applied on roadways with continuously flowing and
38、sufficiently dense traffic that sound levels from single vehicles cannot easily be captured due to sound contamination from other vehicles. In situations where lower traffic volumes allow for the measurement of single vehicle pass-by events without contamination from other vehicles, TP 98, Determini
39、ng the Influence of Road Surfaces on Vehicle Noise Using the Statistical Isolated Pass-By (SIP) Method, or other similar method should be applied. The appropriate measurement technique should be selected based on site and traffic conditions. 5.5. The CTIM test method may be used in conjunction with
40、the on-board sound intensity (OBSI) method described in T 360 that measures the tire/pavement component of vehicle noise exclusively. 6. APPARATUS 6.1. Sound Level InstrumentationThe sound level meter (or equivalent measuring system) shall meet the requirements of a Class 1 instrument according to I
41、EC 61672-1. Note 2It is recommended to use a pressure response/random incidence microphone at grazing incidence (i.e., vertical orientation); see Figure 1. 2018 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable la
42、w.TS-5a TP 99-5 AASHTO Figure 1Illustration of Directions for Microphone Orientation 6.2. WindscreensA windscreen that does not detectably influence the measured sound levels shall be used. 6.3. Frequency Analysis InstrumentationFrequency analysis of the measured sound using one-third octave-band re
43、solution is recommended, but not mandatory. The frequency range of 50 to 10 000 Hz (center frequencies of one-third octave bands) shall be covered. The one-third octave-band filters shall conform to IEC 61260. 6.4. Calibration InstrumentationThe acoustic calibration device used shall meet the requir
44、ements of a Class 1 instrument according to IEC 60942. (Note that some calibrators require correction for environmental conditions. The manufacturers specifications should be consulted.) 6.5. Vehicle Speed Measurement InstrumentationThe average vehicle speed for each lane of travel shall be determin
45、ed. A list of measuring devices/methods is found in Measurement of Highway-Related Noise (FHWA-PD-96-046) and includes radar gun, stopwatch, light sensors, and pneumatic tubes. Care must be taken to avoid interfering with the sound level measurements, including actions that could influence driver be
46、havior and/or generating any intrusive noise caused by a measurement device. The vehicle speed measuring instrument(s) shall have an accuracy of 1 mph (1.6 km/h) for the range of speeds of interest. 6.6. Temperature Measurement InstrumentationThe air temperature measuring instrument(s) shall have an
47、 accuracy of 2F (1.2C). Meters using an infrared technique shall not be used to measure air temperature. 6.7. Traffic Counting InstrumentationTraffic volumes shall be collected. Traffic-counting instrumentation or methods shall not interfere with noise measurements. 6.8. Wind Measurement Instrumenta
48、tionThe wind speed measuring instrument(s) shall have an accuracy of 2 mph (0.9 m/s). The wind direction measuring instrument(s) shall have an accuracy of 10 degrees. 7. SELECTION OF TEST SITES 7.1. The following considerations apply for site selection: 7.1.1. Each road test section shall extend for
49、 a distance of at least four times the distance from the center of the near travel lane to the microphone location in both the up- and down-stream directions from the microphone location. For example, for a microphone located at a distance of 50 ft (15.2 m) Normal IncidenceGrazing IncidenceMicrophoneAxis 2018 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-5a TP 99-6 AASHTO from the center of the near travel lane, the roa
