The provisions of Sec. 391.21 (relating to applications for employment), Sec. 391.23 (relating to investigations and inquiries), and Sec. 391.33 (relating to road tests) do not apply to a driver who has been a single-employer driver (as defined in Sec. 390.5 of this subchapter) of a motor carrier for a continuous period which began before January 1, 1971, as long as he/she continues to be a single-employer driver of that motor carrier. [63 FR 33278, June 18, 1998]