National Highway Borders and Trade Act of 2003

National Highway Borders and Trade Act of 2003 - 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 among border States funds based on a formula which takes into consideration the average annual weight of cargo entering a border State by commercial vehicles across the international borders and the average trade value of all cargo imported and exported. Sets the Federal cost share of projects under this Act at 80 percent.

Directs the Secretary to carry out a program to allocate funds to States for coordinated planning, design, and construction of corridors of national significance.