; and (B) the Secretary determines will not be allocated to the States (or will not be apportioned to the States under section 204 of title 23, United States Code), and will not be available for obligation, for the fiscal year because of the imposition of any obligation limitation for the fiscal year. (2) Ratio Funds shall be distributed under paragraph (1) in the same proportion as the distribution of obligation authority under subsection (c)(5). (3) Availability Funds distributed to each State under paragraph (1) shall be available for any purpose described in section 133(b) of title 23, United States Code. 1103. Definitions Section 101(a) of title 23, United States Code, is amended— (1) in paragraph (4)— (A) in subparagraph (A), by inserting assessing resilience, after surveying, ; (B) in subparagraph (G), by striking and at the end; (C) by redesignating subparagraph (H) as subparagraph (I); and (D) by inserting after subparagraph (G) the following: (H) improvements that reduce the number of wildlife-vehicle collisions, such as wildlife crossing structures; and ; (2) by redesignating paragraphs (17) through (34) as paragraphs (18), (19), (20), (21), (22), (23), (25), (26), (27), (28), (29), (30), (31), (32), (33), (34), (35), and (36), respectively; (3) by inserting after paragraph (16) the following: (17) Natural infrastructure The term natural infrastructure means infrastructure that uses, restores, or emulates natural ecological processes and— (A) is created through the action of natural physical, geological, biological, and chemical processes over time; (B) is created by human design, engineering, and construction to emulate or act in concert with natural processes; or (C) involves the use of plants, soils, and other natural features, including through the creation, restoration, or preservation of vegetated areas using materials appropriate to the region to manage stormwater and runoff, to attenuate flooding and storm surges, and for other related purposes.