Nothing in this regulation shall be construed to relieve any interstate motor common carrier of passengers subject to 49 U.S.C. subtitle IV, part B of any of its obligations under 49 U.S.C. subtitle IV, part B or its certificate(s) of public convenience and necessity. [36 FR 1338, Jan. 28, 1971. Redesignated at 61 FR 54709, Oct. 21, 1996, as amended at 62 FR 15423, Apr. 1, 1997]