49 CFR § 325.21 - Scope of the rules in this subpart.

---
identifier: "/us/cfr/t49/s325.21"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "49 CFR § 325.21 - Scope of the rules in this subpart."
title_number: 49
title_name: "Transportation"
section_number: "325.21"
section_name: "Scope of the rules in this subpart."
chapter_name: "FEDERAL MOTOR CARRIER SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION"
subchapter_number: "A"
subchapter_name: "GENERAL REGULATIONS"
part_number: "325"
part_name: "COMPLIANCE WITH INTERSTATE MOTOR CARRIER NOISE EMISSION STANDARDS"
positive_law: false
currency: "2026-03-24"
last_updated: "2026-03-24"
format_version: "1.1.0"
generator: "[email protected]"
authority: "42 U.S.C. 4917; 49 U.S.C. 301; and 49 CFR 1.87."
regulatory_source: "40 FR 42437, Sept. 12, 1975, unless otherwise noted."
cfr_part: "325"
---


# 325.21 Scope of the rules in this subpart.

The rules in this subpart specify criteria for sound level measurement systems which are used to make the sound level measurements specified in subpart D and subpart E of this part.