Rural Opportunities to Use Transportation for Economic Success Act or the ROUTES Act This bill provides statutory authority for a Department of Transportation (DOT) initiative by establishing the Rural Opportunities to Use Transportation for Economic Success (ROUTES) Office within DOT. The purpose of the office is to (1) improve analysis of projects from rural and tribal areas, and underserved communities in such areas that are applying for DOT discretionary grants, including ensuring that project costs, local resources, and the larger benefits to the American people and economy are appropriately considered; and (2) provide rural, tribal, and underserved communities in these areas with technical assistance for meeting transportation infrastructure investment needs in a financially sustainable manner. To carry out the mission of the office, DOT must establish the ROUTES Council.