Safe Highways and Roads Act of 2003

Safe Highways and Roads Act of 2003 - Amends the Clear Air Act to permit the use of emissions estimates from motor vehicles and necessary emissions reductions contained in a submitted State implementation plan if an approved implementation plan is not available. Deems the estimates adequate if the Administrator of the Environmental Protection Agency does not act within 90 days.

Permits a transportation project to proceed during a conformity lapse of the applicable plan or improvement program if it was included in the first three years of the most recent conforming plan and program and its design concept and scope has not significantly changed.

Requires the Administrator to revise criteria and procedures for determining plan, program, and project conformity.