; and (2) the supplemental notice of proposed rulemaking published on February 13, 2013, titled Accessibility Guidelines for Pedestrian Facilities in the Public Right-of-Way; Shared Use Paths (78 Fed. Reg. 10110). (c) Adoption of regulations Not later than 180 days after the establishment of the guidelines pursuant to subsection (a), the Secretary shall issue such regulations as are necessary to adopt such guidelines. 1607. Highway formula modernization report (a) Highway formula modernization study (1) In general The Secretary of Transportation, in consultation with the American Association of State Transportation Officials and representatives of local governments (including metropolitan planning organizations), shall conduct a highway formula modernization study to assess the method and data used to apportion Federal-aid highway funds under section 104(c) of title 23, United States Code, and issue recommendations on such method and data. (2) Assessment The highway formula modernization study required under paragraph (1) shall include an assessment of, based on the latest available data, whether the apportionment method under such section results in— (A) an equitable distribution of funds based on the estimated tax payments attributable to— (i) highway users in the State that are paid into the Highway Trust Fund; and (ii) individuals in the State that are paid to the Treasury, based on contributions to the Highway Trust Fund from the general fund of the Treasury