Measurement of Highway-Related Noise

Requirements for a REMEL Measurement Plan

1. SITE SELECTION: Identify a minimum of five unique measurement sites for each vehicle type.
   1. Characteristics of the Selected Sites:
      Describe the identified measurement sites, including the approximate ambient noise level at each site.
   2. Microphone Location:
      Identify the locations of all measurement microphones.
   3. Observer Station Location:
      Identify the location of the observer station relative to the microphones, as well as the location of all instrumentation at the observer station.
   4. Vehicle Types:
      Indicate which FHWA TNM vehicle types and/or user-defined vehicle types will be measured.
2. INSTRUMENTATION: List all equipment to be used in the measurements, including the manufacturer, model, and date of last calibration, if applicable, for each item.
3. SAMPLING PERIOD:
   1. Event Quality:
      Identify the rise and fall in the noise-level time-history trace for each event. (NOTE: An instrument capable of measuring and storing the sound level time history, e.g., a graphic level recorder, must be used to establish event quality, and measurements may only be made for vehicles passing in the nearest lane of travel).
   2. Minimum Separation-Distance:
      Indicate the minimum separation-distance between vehicles, which will be used for each event. (NOTE: A minimum separation distance of 400 feet between like-vehicles and a minimum separation distance of 1,000 feet between automobiles and heavy trucks are required).
   3. Number of Samples:
      Identify the minimum number of samples which will be obtained for each vehicle type across the speed range of 10-70 mph, in 10 mph increments. (NOTE: 2,825 automobiles, 765 medium trucks, 2,986 heavy trucks, 355 buses, and 39 motorcycles were sampled in the development of the national REMELs).
4. MEASUREMENT PROCEDURES: Describe the step-by-step procedures which will be used for all field measurements.
5. DATA ANALYSIS:
   1. Calibration and Compilation:
      Show how the measurement data will be adjusted for calibration drift and merged for analysis and the development of REMEL regression equations.
   2. Development of REMEL Regression Equations:
      Show how regression analysis of the measurement data will be used to develop a REMEL equation for each vehicle type.