Section 1331.5 - Additional standards for retaining antitrust immunity by passenger bus industry rate bureaus(a) Rate bureaus must comply with the terms of their agreements, as approved by the Board. Failure to do so will result in lack of immunity for that activity.(b) The bureaus are required to maintain detailed minutes of all meetings where immunized matters are discussed. The bureaus will be subject to withdrawal of their immunity for serious continuing violations of Board standards, and individual tariff publications will be subject to rejection, suspension, or investigation for improprieties in the rate bureau process.(c) Absent Board approval, no other changes may be made in any approved agreement.(d) For the purposes of the statute, the following definitions shall apply: (1) A general increase is a proposed general adjustment of substantially all the rates published in a rate bureau's tariff(s).(2) A broad change in tariff structure modifies in a relatively non-uniform fashion the relationship between most rates published in a rate bureau's tariff, and applies to a large area, either nationally or regionally.(3) An innovative fare will be determined on a case-by-case basis; the Board will, on request, issue opinions on whether particular rate proposals may be regarded as innovative. Two examples of an innovative fare are: (i) A fare for unlimited passenger travel; and(ii) An experimental fare providing for transportation at the passenger's option over the line of one or more carriers.(4) A promotional fare generally has three characteristics: (ii) Attractive price or level of service quality; and(iii) Some added feature in addition to those normally offered.