[Code of Federal Regulations]
[Title 49, Volume 5]
[Revised as of October 1, 2007]
From the U.S. Government Printing Office via GPO Access
[CITE: 49CFR325.1]

[Page 7-8]
 
                        TITLE 49--TRANSPORTATION
 
                      DEPARTMENT OF TRANSPORTATION
 
PART 325_COMPLIANCE WITH INTERSTATE MOTOR CARRIER NOISE EMISSION 
STANDARDS--Table of Contents
 
                      Subpart A_General Provisions
 
Sec.  325.1  Scope of the rules in this part.




                      Subpart A_General Provisions

Sec.  
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.

                   Subpart B_Administrative Provisions

325.11 Issuance, amendment, and revocation of the rules in this part.
325.13 Inspection and examination of motor vehicles.

                        Subpart C_Instrumentation

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.

      Subpart D_Measurement of Noise Emissions; Highway Operations

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.

        Subpart E_Measurement of Noise Emissions; Stationary Test

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.

                      Subpart F_Correction Factors

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.

[[Page 8]]

                   Subpart G_Exhaust Systems and Tires

325.91 Exhaust systems.
325.93 Tires.

    Authority: 42 U.S.C. 4917; 49 U.S.C. 301; 49 CFR 1.73.

    Source: 40 FR 42437, Sept. 12, 1975, unless otherwise noted.

    Editorial Note: Nomenclature changes to part 325 appear at 66 FR 
49869, Oct. 1, 2001.



    (a) The rules in this part prescribe procedures for inspection, 
surveillance, and measurement of motor vehicles and motor vehicle 
equipment operated by motor carriers to determine whether those vehicles 
and that equipment conform to the Interstate Motor Carrier Noise 
Emission Standards of the Environmental Protection Agency, 40 CFR part 
202.
    (b) Except as provided in paragraph (c) of this section, the rules 
in this part apply to motor carriers engaged in interstate commerce. The 
rules apply at any time or under any condition of highway grade, load, 
acceleration or deceleration.
    (c) The rules in this part do not apply to--
    (1) A motor vehicle that has a Gross Vehicle Weight Rating (GVWR) of 
10,000 pounds (4,536 kg.) or less;
    (2) A combination of motor vehicles that has a Gross Combination 
Weight Rating (GCWR) of 10,000 pounds (4,536 kg.) or less;
    (3) The sound generated by a warning device, such as a horn or 
siren, installed in a motor vehicle, unless such device is intentionally 
sounded in order to preclude an otherwise valid noise emission 
measurement;
    (4) An emergency motor vehicle, such as a fire engine, an ambulance, 
a police van, or a rescue van, when it is responding to an emergency 
call;
    (5) A snow plow in operation; or
    (6) The sound generated by auxiliary equipment which is normally 
operated only when the motor vehicle on which it is installed is stopped 
or is operating at a speed of 5 miles per hour (8 kph) or less, unless 
such device is intentionally operated at speeds greater than 5 mph (8 
kph) in order to preclude an otherwise valid noise measurement. Examples 
of that type of auxiliary equipment include, but are not limited to, 
cranes, asphalt, spreaders, ditch diggers, liquid or slurry pumps, 
auxiliary air compressors, welders, and trash compactors.