Safe Highways and Infrastructure Preservation Act

Prohibits a State from allowing the operation of a commercial motor vehicle combination on the National Highway System (except a vehicle or load that cannot be dismantled or divided easily, and that has been issued a special permit under State law) with more than one property-carrying unit (excluding the truck tractor) whose property-carrying units are more than: (1) the maximum combination trailer, semi-trailer, or other type of length limitation allowed by State law on June 1, 2003; or (2) the length of the property-carrying units of those commercial motor vehicle combinations, by specific configuration, in actual and lawful operation on a regular or periodic basis (including continual seasonal operation) in such State on or before June 1, 2003. Permits a commercial motor vehicle combination authorized in a State to continue to operate on System highways provided it is in compliance with State law, including routing-specific and configuration-specific designations and all other restrictions in force in the State on June 1, 2003.

Amends Federal highway law to prohibit a State from allowing the operation of a vehicle or combination (other than a longer combination vehicle) exceeding Interstate weight limits on the Interstate System unless its operation was lawful: (1) on July 1, 1956; (2) in the case of the overall gross weight of any group of two or more consecutive axles, on the date of enactment of the Federal-Aid Highway Amendments of 1974; or (3) under a special permit pursuant to State (grandfather) law. Subjects such vehicles and combinations to all routing-specific, commodity-specific, and weight-specific designations in force in such State on June 1, 2003.

Sets forth requirements with respect to: (1) the operation of vehicles and loads which cannot be easily dismantled or divided (nondivisible loads) on the Federal-aid highway system as they relate to Interstate weight limitations; and (2) waiver of weight limitations for vehicles that operate on the Federal-aid highway system during periods of national emergency.

Declares that Interstate weight limitations on vehicles and combinations (other than longer combination vehicles) that operate on the Interstate System shall also apply to such vehicles and combinations that operate on non-Interstate segments of the National Highway System, unless: (1) such segments are subject to lower State weight limits; or (2) a State allows the operation of any vehicle or combination on an existing non-Interstate segment of the National Highway System that could be so operated lawfully on June 1, 2003. Requires establishment of a model schedule of fines for violations of this Act.