49 C.F.R. § 650.21
For a project for which the Administrator has modified or waived any FTA requirement pursuant to this part, not later than one year after completion of construction, and not later than two years after a project that includes private entity involvement in operations or maintenance activities has entered revenue operations, the recipient shall submit to FTA a report that evaluates the effects of the modification or waiver of Federal requirements on the delivery of the project. The report shall describe the modification or waiver applied to the project; evaluate the success or failure of the modification or waiver; evaluate the extent to which the modification or waiver addressed impediments to greater use of public-private partnerships and private investment in public transportation capital projects; and may include any recommended statutory, regulatory or other changes with an explanation of how the changes would encourage greater use of public-private partnerships and private investment in public transportation capital projects.
49 C.F.R. § 650.21