Tribal Transportation Program Improvement Act of 2003

Tribal Transportation Program Improvement Act of 2003 - Amends the Transportation Equity Act for the 21st Century to authorize appropriations for Indian reservation roads under the Federal Lands Highways Program through FY 2009.

Prohibits the Secretary of Transportation from distributing, for years after FY 2003, any amount of obligation authority made available for Indian reservation road bridges and roads.

Authorizes appropriations to carry out the planning, design, engineering, construction, and inspection of certain projects concerning deficient Indian reservation road bridges.

Raises from two percent to four percent the ceiling for the amount of funds made available for Indian reservation roads for each fiscal year that may be allocated to Indian tribal governments applying for transportation planning pursuant to the Indian Self-Determination and Education Assistance Act.

Requires the Secretary to establish a Federal lands highway program demonstration project for Indian reservation roads and highway bridges located on Indian reservations.

Requires the Secretary to carry out a program to provide to eligible Indian tribes competitive grants for use in establishing tribal transportation safety programs.

Directs the Secretary of Transportation to issue grants to Indian tribes to establish rural transit programs on reservations or other land under tribal jurisdiction.

Expresses the sense of Congress that: (1) the maintenance of roads on Indian reservations is a responsibility of the Bureau of Indian Affairs; and (2) Congress should provide annually to the Bureau funding necessary to carry out all maintenance of roads on Indian reservations.