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Reading the regulations as they stood on October 1, 1998. Current text may differ.Switch to current
Historical textIn force on Oct. 1, 1998Source: annual CFR editions 1996–2004

§ 393.19 Requirements for turn signaling systems.

Wording first on file in the 1996 annual edition, superseded by the 2005 annual edition.

govinfo, 1998 edition ↗
Before Jan. 1, 2017 the record is one snapshot per annual CFR edition, revised as of October 1. This is the 1998 edition's wording. An amendment that took effect between Oct. 1, 1998 and Oct. 1, 1998 would not appear until the next edition, so check the citations below and the Federal Register for exact effective dates.
49 CFR § 393.19 — Requirements for turn signaling systems.. Text in force on October 1, 1998. This wording effective October 1, 1996 to October 1, 2005. Source: govinfo, 1998 edition, https://www.govinfo.gov/app/details/CFR-1998-title49-vol4/CFR-1998-title49-vol4-sec393-19. Retrieved from FMCSR.com, https://fmcsr.com/reg/393.19?asof=1998-10-01, on October 26, 2026. Unofficial compilation; verify against the official source.

(a) Every bus, truck, or truck tractor shall be equipped with a signaling system that in addition to signaling turning movements shall have a switch or combination of switches that will cause the two front turn signals and the two rear turn signals to flash simultaneously as a vehicular traffic hazard warning as required by § 392.22 with the ignition on or off.

(b) Every semitrailer and full trailer shall be equipped so as to have the two rear turn signals to flash simultaneously with the two front turn signals of the towing vehicle as a vehicular traffic hazard warning as required by § 392.22(a).

[53 FR 49397, Dec. 7, 1988]

Amendment history

2 distinct wordings on file since Oct. 1, 1996
  1. Oct. 1, 2005 → presentannual editions 2005–2016diff vs. previous
    [70 FR 48046, Aug. 15, 2005]
  2. Oct. 1, 1996 → Oct. 1, 2005annual editions 1996–2004viewing
    [53 FR 49397, Dec. 7, 1988]

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.