Commercial Truck Highway Safety Demonstration Program Act of 2003 - Directs the Secretary of Transportation to carry out a program to demonstrate the effects on the safety of the highway network in Maine of permitting operation on the Interstate System highways within the State of a vehicle that weighs over 80,000 pounds, that consists of a three-axle tractor unit hauling a single trailer or semitrailer, and that does not exceed any vehicle weight limitation applicable under Maine law.
Waives highway funding reduction relating to weight of vehicles using Interstate System highways with respect to vehicles allowed pursuant to this program.
Provides for program termination and for the responsibilities of the State of Maine, including: (1) submitting a plan to the Secretary of Transportation; (2) establishing a highway safety committee; and (3) collecting data on the net effects of the operation of such vehicles on safety.