Rural Four-Lane Highway Safety and Development Act of 2003

Rural Four-Lane Highway Safety and Development Act of 2003 - Directs the Secretary of Transportation to establish and carry out a program to make allocations to States for projects to expand eligible two-lane highways in rural areas to four-lane highways. Authorizes the Secretary to make allocations only for projects that are on the National Highway System (NHS) or a high priority corridor identified under the Intermodal Surface Transportation Efficiency Act of 1991.

Directs the Secretary to give priority to projects: (1) to improve highway safety on the most dangerous rural two-lane highways on the NHS; (2) carried out on rural highways with respect to which the annual volume of commercial vehicle traffic has increased since the enactment of the North American Free Trade Agreement Implementation Act or is expected to increase after this Act's enactment; (3) carried out on rural highways with high levels of commercial truck traffic; and (4) on highway corridors that will help stimulate regional economic growth and development in rural areas.