Historical textIn force on Oct. 1, 1996Source: annual CFR edition 1996

§ 391.99 Reasonable cause testing requirements.

Wording first on file in the 1996 annual edition, superseded by the 1998 annual edition. The section was then removed.

govinfo, 1996 edition ↗

Before Jan. 1, 2017 the record is one snapshot per annual CFR edition, revised as of October 1. This is the 1996 edition's wording. An amendment that took effect between Oct. 1, 1996 and Oct. 1, 1996 would not appear until the next edition, so check the citations below and the Federal Register for exact effective dates.

49 CFR § 391.99 — Reasonable cause testing requirements.. Text in force on October 1, 1996. This wording effective October 1, 1996 to October 1, 1998. Source: govinfo, 1996 edition, https://www.govinfo.gov/app/details/CFR-1996-title49-vol4/CFR-1996-title49-vol4-sec391-99. Retrieved from FMCSR.com, https://fmcsr.com/reg/391.99?asof=1996-10-01, on October 26, 2026. Unofficial compilation; verify against the official source.

(a) A motor carrier shall require a driver to be tested, upon reasonable cause, for the use of controlled substances.

(b) A driver shall submit to testing, upon reasonable cause, for the use of controlled substances when requested to do so by the motor carrier.

(c) The conduct must be witnessed by at least two supervisors or company officials, if feasible. If not feasible, only one supervisor or company official need witness the conduct. The witness or witnesses must have received training in the identification of actions, appearance, or conduct of a commercial motor vehicle driver which are indicative of the use of a controlled substance.

(d) The documentation of the driver's conduct shall be prepared and signed by the witnesses within 24 hours of the observed behavior or before the results of the tests are released, whichever is earlier.

[53 FR 47151, Nov. 21, 1988, as amended at 55 FR 3556, Feb. 1, 1990]

Amendment history

1 distinct wording on file since Oct. 1, 1996

Oct. 1, 1996 → Oct. 1, 1998annual edition 1996viewing
[53 FR 47151, Nov. 21, 1988, as amended at 55 FR 3556, Feb. 1, 1990]

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.