Historical textIn force on Oct. 1, 2004Source: annual CFR editions 2003–2004

§ 393.48 Brakes to be operative.

Wording in the annual edition revised as of Oct. 1, 2003, superseded by the 2005 annual edition.

govinfo, 2004 edition ↗

Compare with

Before Jan. 1, 2017 the record is one snapshot per annual CFR edition, revised as of October 1. This is the 2004 edition's wording. An amendment that took effect between Oct. 1, 2004 and Oct. 1, 2004 would not appear until the next edition, so check the citations below and the Federal Register for exact effective dates.

49 CFR § 393.48 — Brakes to be operative.. Text in force on October 1, 2004. This wording effective October 1, 2003 to October 1, 2005. Source: govinfo, 2004 edition, https://www.govinfo.gov/app/details/CFR-2004-title49-vol4/CFR-2004-title49-vol4-sec393-48. Retrieved from FMCSR.com, https://fmcsr.com/reg/393.48?asof=2004-10-01, 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, all brakes with which a motor vehicle is equipped must at all times be capable of operating.

(b) Devices to reduce or remove front-wheel braking effort. A motor vehicle may be equipped with a device to reduce the braking effort upon its front wheels or, in the case of a three-axle truck or truck tractor manufactured before March 1, 1975, to remove the braking effort upon its front wheels, if that device conforms to, and is used in compliance with, the rules in paragraph (b) (1) or (2) of this section.

(1) Manually operated devices. A manually operated device to reduce or remove the front-wheel braking effort must not be—

(i) Installed in a motor vehicle other than a bus, truck, or truck tractor; or

(ii) Installed in a bus, truck, or truck tractor manufactured after February 28, 1975; or

(iii) Used in the reduced mode except when the vehicle is operating under adverse conditions such as wet, snowy, or icy roads.

(2) Automatic devices. An automatic device to reduce the front-wheel braking effort by up to 50 percent of the normal braking force, regardless of whether or not antilock system failure has occurred on any axle, must not—

(i) Be operable by the driver except upon application of the control that activates the braking system; and

(ii) Be operable when the pressure that transmits brake control application force exceeds—

(A) 85 psig on air-mechanical braking systems; or

(B) 85 percent of the maximum system pressure in the case of vehicles utilizing other than compressed air.

(1) A disabled vehicle being towed; or

(2) A vehicle being towed in a driveaway-towaway operation which is exempt from the general rule of § 393.42 under paragraph (b) of that section.

[39 FR 26907, July 24, 1974, as amended at 41 FR 29130, July 15, 1976; 41 FR 53031, Dec. 3, 1976; 67 FR 61824, Oct. 2, 2002]

Amendment history

4 distinct wordings on file since Oct. 1, 1996

Oct. 1, 2007 → presentannual editions 2007–2016diff vs. previous
[70 FR 48051, Aug. 15, 2005, as amended at 72 FR 9870, Mar. 6, 2007]
Oct. 1, 2005 → Oct. 1, 2007annual editions 2005–2006diff vs. previous
[70 FR 48051, Aug. 15, 2005]
Oct. 1, 2003 → Oct. 1, 2005annual editions 2003–2004diff vs. previousviewing
[39 FR 26907, July 24, 1974, as amended at 41 FR 29130, July 15, 1976; 41 FR 53031, Dec. 3, 1976; 67 FR 61824, Oct. 2, 2002]
Oct. 1, 1996 → Oct. 1, 2003annual editions 1996–2002
[39 FR 26907, July 24, 1974, as amended at 41 FR 29130, July 15, 1976; 41 FR 53031, Dec. 3, 1976]

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.