Historical textIn force on Oct. 1, 1997Source: annual CFR editions 1996–2012

§ 325.1 Scope of the rules in this part.

Wording first on file in the 1996 annual edition, superseded by the 2013 annual edition.

govinfo, 1996 edition ↗

Compare with

Before Jan. 1, 2017 the record is one snapshot per annual CFR edition, revised as of October 1. This is the 1996 edition's wording. An amendment that took effect between Oct. 1, 1997 and Oct. 1, 1997 would not appear until the next edition, so check the citations below and the Federal Register for exact effective dates. govinfo does not publish the 1997 edition of Parts 300–399 in machine-readable form, so the 1996 text is shown for that year.

49 CFR § 325.1 — Scope of the rules in this part.. Text in force on October 1, 1997. This wording effective October 1, 1996 to October 1, 2013. Source: govinfo, 1996 edition, https://www.govinfo.gov/app/details/CFR-1996-title49-vol4/CFR-1996-title49-vol4-sec325-1. Retrieved from FMCSR.com, https://fmcsr.com/reg/325.1?asof=1997-10-01, on October 26, 2026. Unofficial compilation; verify against the official source.

(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.

(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.

Amendment history

2 distinct wordings on file since Oct. 1, 1996

Oct. 1, 2013 → presentannual editions 2013–2016diff vs. previous
[40 FR 42437, Sept. 12, 1975, as amended at 78 FR 58477, Sept. 24, 2013]
Oct. 1, 1996 → Oct. 1, 2013annual editions 1996–2012viewing

A new entry appears whenever the regulatory words change between government snapshots. Day-precise from the eCFR (2017 onward); before that, one snapshot per annual CFR edition (revised as of October 1). Bracketed citations are the Federal Register history printed with the section.