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  • § 325.1
    Scope of the rules in this part.
  • § 325.3
    Effective date.
  • § 325.5
    Definitions.
  • § 325.7
    Allowable noise levels.
  • § 325.9
    Measurement tolerances.
  • § 325.11
    Issuance, amendment, and revocation of the rules in this part.
  • § 325.13
    Inspection and examination of motor vehicles.
  • § 325.21
    Scope of the rules in this subpart.
  • § 325.23
    Type of measurement systems which may be used.
  • § 325.25
    Calibration of measurement systems.
  • § 325.27
    Use of a windscreen.
  • § 325.31
    Scope of the rules in this subpart.
  • § 325.33
    Site characteristics; highway operations.
  • § 325.35
    Ambient conditions; highway operations.
  • § 325.37
    Location and operation of sound level measurement system; highway operations.
  • § 325.39
    Measurement procedure; highway operations.
  • § 325.51
    Scope of the rules in this subpart.
  • § 325.53
    Site characteristics; stationary test.
  • § 325.55
    Ambient conditions; stationary test.
  • § 325.57
    Location and operation of sound level measurement systems; stationary test.
  • § 325.59
    Measurement procedure; stationary test.
  • § 325.71
    Scope of the rules in this subpart.
  • § 325.73
    Microphone distance correction factors.
  • § 325.75
    Ground surface correction factors.
  • § 325.77
    Computation of open site requirements—nonstandard sites.
  • § 325.79
    Application of correction factors.
  • § 325.91
    Exhaust systems.
  • § 325.93
    Tires.

Part 325
COMPLIANCE WITH INTERSTATE MOTOR CARRIER NOISE EMISSION STANDARDS

§ 325.71: Scope of the rules in this subpart.

(a) The rules in this subpart specify correction factors which are added to, or subtracted from, the reading of the sound level generated by a motor vehicle, as displayed on a sound level measurement system, during the measurement of the motor vehicle's sound level emissions at a test site which is not a standard site.
(b) The purpose of adding or subtracting a correction factor is to equate the sound level reading actually generated by the motor vehicle to the sound level reading it would have generated if the measurement had been made at a standard test site.