(a) The respondents shall submit a traffic study for the most current 12-month calendar year available, which shall be referred to as the “base-calendar year—actual.” This year shall be the calendar year that has ended at least 7 months prior to the published effective date of the tariff schedules. If the effective date is less than 7 months following the end of the preceding calendar year, than the second preceding calendar year shall be considered at the “base-calendar year—actual.” The study shall include a probability sampling of the actual traffic handled during identical time periods for each study carrier.

(b) The study carriers shall consist of those carriers subject to the requirements for allocation of expenses between line-haul and pickup and delivery services, as provided in Part 1207 of this chapter, Instructions 27 and 9002, which participate in one of the motor carrier industry's Continuous Traffic Studies, and which derive either $1 million or more in annual operating revenues from this issue traffic or 1 percent or more of the total annual operating revenues of all carriers from the issue traffic. A list of such carriers and the appropriate revenue data shall be submitted to corroborate the selection of the study carriers. “Issue traffic” consists of those shipments on which the freight rates or charges would be affected by the rate proposal.

(c) Respondents shall take a sample of the traffic handled by the study carriers according to acceptable standards of probability sampling principles and practices, and shall explain and evaluate the probability sample from the standpoint of: Purpose, sample design (including explanation of estimation procedure and disclosure of sampling errors for derived characteristics), quality control aspects involved in processing and tabulating data and any statistical analysis performed on the sampled data. 4