; or (2) to affect any request for the issuance, revision, revocation, or incorporation into regulation of any guidance under this subtitle made before December 31, 2018. . (b) Table of contents The table of contents for chapter 201, as amended by section 114, is further amended by inserting after the item relating to section 20125 the following: 20126. Guidance. . 116. Regulatory impact analyses (a) In general Subchapter I of chapter 201, as amended by section 115, is further amended by adding at the end the following: 20127. Regulatory impact analyses (a) In general Before issuing any proposed rule or final rule under this subtitle, the Secretary of Transportation shall conduct a regulatory impact analysis to evaluate the proposed rule or final rule, as applicable. (b) Regulatory impact analyses An analysis under subsection (a) shall— (1) be based upon the best reasonably obtainable supporting information, consistent with section 20122; (2) describe the need to be addressed and how the rule addresses that need; (3) analyze effects, including the benefits and costs, of the rule; (4) to the maximum extent practicable, consider the cumulative regulatory burden on the regulated entity under subsection (d); (5) consider the effects on different types and sizes of businesses, if applicable; (6) for a proposed rule that is likely to lead to a significant rule, or a final rule that is a significant rule— (A) describe the need to be addressed, including— (i) the supporting information demonstrating the need; (ii) the failures of private markets that warrant new agency action, if applicable; and (iii) whether existing law, including regulations, has created or contributed to the need; (B) define the baseline for the analysis; (C) set the timeframe of the analysis; (D) analyze any available regulatory alternatives, including— (i) if rulemaking is not specifically directed by statute, the alternative of not regulating