; and (2) detailing, based on the best available science, what types of projects eligible for assistance under this section are not expected to provide significant greenhouse gas emissions reductions from the surface transportation sector. . (b) Clerical amendment The analysis for chapter 1 of title 23, United States Code, is amended by adding at the end the following new item: 171. Carbon pollution reduction. . 1214. Recreational trails Section 206 of title 23, United States Code, is amended by adding at the end the following: (j) Use of other apportioned funds Funds apportioned to a State under section 104(b) that are obligated for recreational trails and related projects shall be administered as if such funds were made available for purposes described under this section. . 1215. Safe routes to school program (a) In general Chapter 2 of title 23, United States Code, is amended by inserting after section 210 the following: 211. Safe routes to school program (a) Program The Secretary shall carry out a safe routes to school program for the benefit of children in primary, middle, and high schools. (b) Purposes The purposes of the program shall be— (1) to enable and encourage children, including those with disabilities, to walk and bicycle to school; (2) to make bicycling and walking to school a safer and more appealing transportation alternative, thereby encouraging a healthy and active lifestyle from an early age