the role of vertically integrated operations in facilitating subsidization of sales of motor fuel at wholesale or retail;

the extent to which such subsidization is predatory and presents a threat to competition;

the profitability of various segments of the petroleum industry;

the impact of prohibiting such subsidization on the competitive viability of various segments of the petroleum industry, on prices of motor fuel to consumers and on the health and structure of the petroleum industry as a whole; and

such other matters as the Secretary considers appropriate.

The Secretary shall report the results of the study required by this section, together with such recommendations for legislative action and such statistical evidence as he deems appropriate to the Congress on or before the expiration of the eighteenth month after June 19, 1978.

If the President determines that interim measures are necessary and appropriate to maintain the competitive viability of the marketing sector of the petroleum industry during Congressional consideration of the recommendations contained in the report submitted under paragraph (1), he shall prescribe, by rule, in accordance with the procedures set forth in section 6393(a) of title 42 such interim measures.

No interim measure proposed by the President under this section may be submitted after January 1, 1980, and the effect of such measure if approved by the Congress under paragraph (4) may not extend beyond 18 months after such Congressional approval.

Such interim measure shall not take effect unless approved by both Houses of Congress as if it were a contingency plan under section 6422 of title 42: Provided, That the 60-day period referred to in such section shall be extended to 90 days for purposes of this section.