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Highway Traffic and Construction Noise - Regulation and Guidance

SAMPLE Data Acquisition Plan


  1. Introduction

    The Quiet Pavement Pilot Program will evaluate the highway traffic noise reduction benefits gained from the use of various pavement types and/or textures. However, safety and durability remain the most important factors in pavement type and/or texture considerations. Accordingly, this data acquisition plan includes the collection of data not only related to highway traffic noise characteristics but also to the safety and durability aspects of the associated pavements. The plan is intended to collect data necessary to accomplish the following:

    1. Quantify the acoustic properties of new pavement as compared to existing pavement;
    2. Quantify the variation of pavement acoustic properties with age;
    3. Quantify variation of pavement acoustic properties with season;
    4. Determine the correlation (if any) between physical pavement characteristics (such as macrotexture, void content, impedance) and the pavement acoustic properties, so that acoustical performance can be determined by the physical observation of pavement; and
    5. (Optional) Determine the correlation between wayside and near-field acoustical measurements, so that near-field measurements alone may be used for future pavement noise evaluations.
  2. Data Collection

    All data should be collected and analyzed in general conformance with ANSI S12.8-1998 and ANSI S1.13-1995 and FHWA's procedures, Measurement of Highway-Related Noise (FHWA-PD-96-046).

    1. Measurement sites must meet Reference Energy Mean Emission Level-type criteria including the following:
      1. Relatively flat terrain;
      2. Free from reflective objects; and
      3. Free from electromagnetic interference.
    2. Types of data to be collected include the following (the specifications for each data type are presented later in the plan):
      1. Wayside acoustical data;
      2. Pavement data;
      3. Traffic data;
      4. Safety data;
      5. Meteorological data; and
      6. (Optional) Near-field acoustical data (required if near-field measurements are to be used to characterize pavements - must be accompanied by simultaneous wayside acoustical measurements [wayside measurements (measurements with stationary microphones) will be taken at Site 3 locations (research grade sites) and Site 2 locations (selected residence sites - approximately 18 locations for 6 projects)]
        1. Acoustic intensity method
        2. CPX trailer method (ISO 11819-2)
    3. Before measurements begin, FHWA must approve the following information as submitted by the State DOT:
      1. The location and description of all measurement sites; and
      2. The measurement methodology, including specific instrumentation and procedures to be used.
  3. Data Analysis

    All data should be collected and analyzed in general conformance with ANSI S12.8-1998 and ANSI S1.13-1995 and FHWA's procedures, Measurement of Highway-Related Noise (FHWA-PD-96-046).

    1. Differences between measurement pairs (measurements made at different times at a single site, or at different sites) must be accounted for during analysis for the following:
      1. Traffic composition and speeds;
      2. Meteorological conditions; and
      3. Site characteristics, such as ground cover.
    2. Analysis must include sufficient data to represent typical traffic composition and speed, as well as the variation in expected meteorological conditions for the subject area.
  4. Development of a Pavement Adjustment Factor Based Upon Ongoing Measurements

    1. At least one day of measurements is required to obtain enough data to calculate an adjustment factor for a single site under one set of conditions (this may not apply to the existing traffic pass-by method, where more than one day of measurements may be required in order to obtain a sufficient amount of data). This requires:
      1. 6 hours for continuous flow; or
      2. The number of hours it takes to collect the minimum number of clean pass-by events.
    2. To obtain an overall adjustment factor, a minimum of three sites is needed, with data collected over time and in different seasons, such that the expected ranges of conditions (for traffic composition and speeds, meteorological conditions, and site characteristics) for the subject area are included in the measurements.
  5. Wayside Acoustical Data
    1. Measurement Methods (there are three possible types; the choice of type is made based upon the possibility of road closures, density of traffic, etc.):
      1. Continuous Flow
        1. Measure time-averaged sound levels (15 min, LAeq); and
        2. Traffic must be constant and heavy enough for uninterrupted data blocks and must be representative of composition and speeds typical of subject area.
      2. Controlled Pass-Bys
        1. Measure LAmax for each vehicle;
        2. Number of pass-bys must meet the criteria for the statistical pass-by method (SPB; ISO 11819-1); and
        3. Apply the SPB to get the statistical pass-by index (SPBI).
      3. Existing Traffic Pass-Bys
        1. Measure LAmax for each vehicle;
        2. Number of pass-bys must meet the criteria for the statistical pass-by method (SPB; ISO 11819-1); and
        3. Apply the SPB to get the statistical pass-by index (SPBI).
    2. Data Collection
      1. Microphone Position(s)
        1. Required location: distance of 50 ft from the center of the near travel lane, height 5 ft above the ground; and
        2. Optional locations: distance 50 ft, height 15 ft; distance 25ft, height 5 ft.
      2. Collection Requirements
        1. Sound levels (LAeq, LAmax), as specified in section 5.a (Measurement Methods);
        2. One-third octave-band data (ANSI/ISO Bands 17 through 40, nominal frequencies of 50 Hz through 10 kHz) - a spectrum analyzer must be used either directly in the field, or later with recorded data; and
        3. Acoustic data must be recorded (DAT recorder).
      3. Equipment Specifications
        1. Microphones and sound level meters must conform to ANSI S1.4 Type 1;
        2. Spectrum analyzers must conform to ANSI S1.11 Type 2 (or IEC 61260 Class 2); and
        3. FHWA must approve all instrumentation prior to its use.
  6. Pavement Data
    1. Collection Requirements
      1. Obtain pavement specifications for construction (construction date, mix design, pavement thickness, etc.) for:
        1. Existing pavement (as a minimum, identify the approximate age, general type, and texture specified for the pavement); and
        2. New pavement.
      2. Measure actual pavement properties of new construction (not as stated in specifications):
        1. Macrotexture (use core samples, ROSAN, or other method); document the (1) Mean Texture Depth ( MTD) ASTM E-965; and (2) Mean Profile Depth ( MPD) ASTM E-2157-01 or ASTM E-1845/ISO 13473 [Note: The CT Meter will be used to measure surface texture];
        2. Void content, if possible (use core samples or other method;
        3. Pavement temperature measured periodically, at least once each hour (preferably once for each pass-by when implementing one of the pass-by methods); and
        4. (Optional) Acoustic impedance of the pavement.
  7. Traffic Data
    1. Measurement Methods (type dependent on acoustical measurement type and available staff/equipment):
      1. Record all vehicles with a video camera and extract information at a later time (for continuous flow traffic or single vehicle pass-bys);
      2. Log all traffic information (for single vehicle pass-bys).
    2. Collection Requirements - collect the following information during all acoustical measurements:
      1. Vehicle type in 5 categories (automobile, medium truck, heavy truck, bus, and motorcycle); and
      2. Vehicle speeds
        1. Pass-by method: speed for each vehicle
        2. Continuous flow method: average speeds during specified time blocks
        3. Traffic speeds can be measured using traffic cones for timing, radar, pneumatic line, etc. (note: speed measurement methods must not interfere with acoustic data collection or influence driver behavior).
  8. Safety Data
    1. Measurement Methods (utilize one or both methods)
      • Wet Weather Crash Performance: wet-weather and/or total vehicle crash rates at the same or similar locations.
      • Friction Test Results: friction test results and speed gradient when tested in conformance with ASTM E-274 (skid trailer) using the smooth tire (ASTM E-524), or International Friction Index (IFI) [ASTM E-1960]
    2. Collection Requirements
      • Duration: data collection shall be of sufficient duration to demonstrate adequate long-term safety performance of pavement surfaces.
      • Scope: safety performance indicators will be collected from both "control" sections and "Quiet Pavement Pilot Program/quiet pavement research" sections
  9. Meteorological Data
    1. Meteorological Sensor Location(s)
      1. Must be close enough to the microphone location so that weather measurements represent conditions at the microphone
    2. Collection Requirements - collect the following during all acoustical measurements (continuous for continuous flow traffic and during each event for single vehicle pass-bys):
      1. Air temperature;
      2. Wind speed;
      3. Wind direction; and
      4. Relative humidity.
Updated: 7/14/2011
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