§FMCSR.com
Current textIn force on July 23, 2019Source: eCFR

§ 393.49 Control valves for brakes.

Current wording, in the annual edition revised as of Oct. 1, 2013.

eCFR as of July 23, 2019 ↗
49 CFR § 393.49 — Control valves for brakes.. Text in force on July 23, 2019. This wording effective October 1, 2013 to present. Source: eCFR as of July 23, 2019, https://www.ecfr.gov/on/2019-07-23/title-49/section-393.49. Retrieved from FMCSR.com, https://fmcsr.com/reg/393.49?asof=2019-07-23, on October 26, 2026. Unofficial compilation; verify against the official source.

(a) General rule. Except as provided in paragraphs (b) and (c) of this section, every motor vehicle manufactured after June 30, 1953, which is equipped with power brakes, must have the braking system so arranged that one application valve must when activated cause all of the service brakes on the motor vehicle or combination motor vehicle to operate. This requirement must not be construed to prohibit motor vehicles from being equipped with an additional valve to be used to operate the brakes on a trailer or trailers or as required for buses in § 393.44.

(b) Driveaway-Towaway Exception. This section is not applicable to driveaway-towaway operations unless the brakes on such operations are designed to be operated by a single valve.

(c) Surge brake exception. This requirement is not applicable to trailers equipped with surge brakes that satisfy the conditions specified in § 393.48(d).

[72 FR 9871, Mar. 6, 2007, as amended at 78 FR 58484, Sept. 24, 2013]

Amendment history

3 distinct wordings on file since Oct. 1, 1996
  1. Oct. 1, 2013 → presentannual editions 2013–2016diff vs. previousviewing
    [72 FR 9871, Mar. 6, 2007, as amended at 78 FR 58484, Sept. 24, 2013]
  2. Oct. 1, 2007 → Oct. 1, 2013annual editions 2007–2012diff vs. previous
    [72 FR 9871, Mar. 6, 2007]
  3. Oct. 1, 1996 → Oct. 1, 2007annual editions 1996–2006

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.