Safe Highways and Infrastructure Preservation Act - Prohibits a state from prescribing or enforcing any regulation that allows a restricted property-carrying unit (any trailer, semitrailer, container, or other property-carrying unit longer than 53 feet, except for a fire-fighting unit) to operate on the National Highway System (NHS) (including the Interstate System), unless the operation of such unit is authorized by the state on June 1, 2008, and in actual and lawful operation on a regular or periodic basis (including seasonal operations) on or before that date. Prohibits a state from allowing the operation of a commercial motor vehicle combination on the NHS (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:
Prohibits 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:
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 NHS, unless: