National Highway Borders Act of 2005 - Directs the Secretary of Transportation to establish and implement a coordinated border infrastructure program under which the Secretary shall make allocations to border States (i.e., States with a common boundary with Canada or Mexico) for projects within a border region (the portion of a border State located within 100 kilometers of a land border crossing with Canada or Mexico) to improve the safe movement of people and goods at or across the U.S.-Canadian and U.S.-Mexican borders.
Permits allocations to States to be used in a border region only for specified: (1) improvements to transportation and supporting infrastructure that facilitate cross-border vehicle and cargo movement; (2) construction of highways and related safety and safety enforcement facilities; (3) operational improvements; (4) international coordination of planning, programming, and border operation; (5) projects in Canada or Mexico proposed by border States that directly and predominantly facilitate cross-border vehicle and commercial cargo movements; and (6) planning and environmental studies.
Directs the Secretary to allocate funds among border States on the basis of a specified formula. Sets the Federal cost share of projects under this Act at 80 percent.