Historical textIn force on Sept. 30, 2013Source: annual CFR editions 2001–2012

§ 325.7 Allowable noise levels.

Wording in the annual edition revised as of Oct. 1, 2001, superseded by the 2013 annual edition.

govinfo, 2012 edition ↗

Compare with

Before Jan. 1, 2017 the record is one snapshot per annual CFR edition, revised as of October 1. This is the 2012 edition's wording. An amendment that took effect between Oct. 1, 2012 and Sept. 30, 2013 would not appear until the next edition, so check the citations below and the Federal Register for exact effective dates.

49 CFR § 325.7 — Allowable noise levels.. Text in force on September 30, 2013. This wording effective October 1, 2001 to October 1, 2013. Source: govinfo, 2012 edition, https://www.govinfo.gov/app/details/CFR-2012-title49-vol5/CFR-2012-title49-vol5-sec325-7. Retrieved from FMCSR.com, https://fmcsr.com/reg/325.7?asof=2013-09-30, on October 26, 2026. Unofficial compilation; verify against the official source.

Motor vehicle noise emissions, when measured according to the rules of this part, shall not exceed the values specified in Table 1.

Table 1—Maximum Permissible Sound Level Readings (Decibel (A)) ^1,2
	Highway operation test	Soft site	35 mi/h or less	Above 35 mi/h	Hard Site	35 mi/h or less
If the distance between the microphone location point and the microphone target point is—
31 ft (9.5m) or more but less than 35 ft (10.7m)	87	91	89	93	89	91
35 ft (10.7m) or more but less than 39 ft (11.9m)	86	90	88	92	88	90
39 ft (11.9m) or more but less than 43 ft (13.1m)	85	89	87	91	87	89
43 ft (13.1m) or more but less than 48 ft (14.6m)	84	88	86	90	86	88
48 ft (14.6m) or more but less than 58 ft (17.1m)	83	87	85	89	85	87
58 ft (17.1m) or more but less than 70 ft (21.3m)	82	86	84	88	84	86
70 ft (21.3m) or more but less than 83 ft (25.3m)	81	85	83	87	83	85

¹ The speeds shown refer to measurements taken at sites having speed limits as indicated. These speed limits do not necessarily have to be posted.

² This table is based on motor carrier noise emission requirements specified in 40 CFR 202.20 and 40 CFR 202.21.

[40 FR 42437, Sept. 12, 1975, as amended at 54 FR 50385, Dec. 6, 1989]

Amendment history

4 distinct wordings on file since Oct. 1, 1996

Jan. 1, 2017 → presenteCFR, day-precisediff vs. previous
[40 FR 42437, Sept. 12, 1975, as amended at 54 FR 50385, Dec. 6, 1989]
Oct. 1, 2013 → Jan. 1, 2017annual editions 2013–2016diff vs. previous
[40 FR 42437, Sept. 12, 1975, as amended at 54 FR 50385, Dec. 6, 1989]
Oct. 1, 2001 → Oct. 1, 2013annual editions 2001–2012diff vs. previousviewing
[40 FR 42437, Sept. 12, 1975, as amended at 54 FR 50385, Dec. 6, 1989]
Oct. 1, 1996 → Oct. 1, 2001annual editions 1996–2000
[40 FR 42437, Sept. 12, 1975, as amended at 54 FR 50385, Dec. 6, 1989]

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.