; and (B) include an assessment of progress made by the Secretary in advancing safety regulations. (d) Data collection Not later than 1 year after the date of enactment of this Act, the Secretary shall implement recommendations 1 and 2 described in the report by the Government Accountability Office published on March 14, 2019, titled Truck Underride Guards: Improved Data Collection, Inspections, and Research Needed (GAO–19–264). 4406. Transportation of horses Section 80502 of title 49, United States Code, is amended— (1) in subsection (c), by striking This section does not and inserting Subsections (a) and (b) shall not ; (2) by redesignating subsection (d) as subsection (e); (3) by inserting after subsection (c) the following: (d) Transportation of horses (1) Prohibition No person may transport, or cause to be transported, a horse from a place in a State, the District of Columbia, or a territory or possession of the United States through or to a place in another State, the District of Columbia, or a territory or possession of the United States in a motor vehicle containing 2 or more levels stacked on top of each other. (2) Motor vehicle defined In this subsection, the term motor vehicle — (A) means a vehicle driven or drawn by mechanical power and manufactured primarily for use on public highways; and (B) does not include a vehicle operated exclusively on a rail or rails. ; and (4) in subsection (e), as redesignated— (A) by striking A rail carrier and inserting the following: (1) In general A rail carrier ; (B) by striking this section and inserting subsection (a) or (b)