Opinion for the court per curiam.

We affirm the order of the Interstate Commerce Commission invalidating petitioner’s tariffs as violative of the Motor Carrier Act’s prohibition of collective rate-making for “single-line rates.” See 49 U.S.C. § 10706(b)(3)(D) (1982). Although the Act’s definition of “single-line rate” is not free from ambiguity, see 49 U.S.C. § 10706(b)(1) (1982), its legislative history leaves no doubt that Congress intended to prohibit collective ratemaking for transportation service provided by a single carrier from shipper to consignee. This prohibition applies whether or not other carriers provide the same single-line service at the same rate. See H.R.Rep. No. 1069, 96th Cong., 2d Sess. 27-28 (1980), U.S.Code *2Cong. & Admin.News 1980, p. 2283; S.Rep. No. 641, 96th Cong., 2d Sess. 13 (1980). See also Western Railroads — Agreement, 358 ICC 662, 667-670 (1978) (interpreting an identical prohibition on collective rate-making for “single-line rates” in the “4R” Act two years prior to the passage of the Motor Carrier Act); Motor Carrier Rate-making Study Comm’n, Collective Rate-making in the Trucking Industry 499 (1983) (supporting this interpretation of “single-line rate” after passage of the Act). Petitioner suggests, however, that the prohibition on single-line rates was merely intended to prevent collective ratemaking for rates that were proposed by a single carrier and where no other carrier provides that service at that rate. As we read petitioner's definition, it would make the prohibition on single-line rates wholly redundant of the provisions of the Act that already allow for “independent action” by a single carrier. See 49 U.S.C. § 10706(b)(3)(B)(ii) (1982). Given the fundamental importance of the Motor Carrier Act’s repeal of antitrust immunity for single-line ratemaking, see S.Rep. No. 641, supra, at 13, petitioner’s interpretation borders on the frivolous.

Affirmed.