(a) Upon the filing by the National Bus Traffic Association, Inc., (NBTA) on behalf of its carrier members, or by such other agencies as the Board may by order otherwise designate, of agency tariff schedules which contain proposed general increases in fares or charges where such proposal would result in an increase of $1 million or more in the annual operating revenues on the traffic affected by the proposal, the motor common carriers of passengers on whose behalf such schedules are filed shall, concurrently with the filing of those schedules, file and serve, as provided hereinafter, a verified statement presenting and comprising the entire evidential case which is relied upon to support the proposed general increase. Carriers thus required to submit their evidence when they file their schedules are hereby notified that special permission to file those schedules shall be conditioned upon the publishing of an effective date at least 30 days later than the date of filing, to enable proper evaluation of the evidence presented. Data to be submitted in accordance with Sec. Sec. 1139.21 through 1139.23 represent the minimum data required to be filed and served, and in no way shall be considered as limiting the type of evidence that may be presented at the time of filing of the schedules. If a formal proceeding is instituted, the carriers are not precluded from updating the evidence submitted at the time of filing of the schedules to reflect the current situation.
(b) When filing tariff schedules other than those described hereinabove, the carriers or their tariff publishing agencies shall be required to comply with such procedures as the Board may direct in the event an investigation is instituted. Nothing stated in this part shall relieve the carriers of their burden of proof imposed under the Interstate Commerce Act. [42 FR 40860, Aug. 12, 1977. Redesignated at 47 FR 49577, Nov. 1, 1982, and amended at 51 FR 6238, Feb. 21, 1986]