State Highways and Infrastructure Preservation Act of 1994

Safe Highways and Infrastructure Preservation Act of 1994 - Amends the Surface Transportation Assistance Act of 1982 to prohibit States from allowing the operation on federally assisted highways of any trailer, semi-trailer, container, or other cargo carrying unit longer than 53 feet, with specified exceptions. Declares that nothing in this Act shall be construed to affect State laws with respect to such vehicles less than 53 feet long.

(Sec. 3) Amends Federal highway law to prohibit States from allowing the operation of any vehicle or combination (other than longer combination vehicles) that are not in conformance with the Interstate weight limits, unless the Department of Transportation, another Federal agency, or the State has determined such vehicles could lawfully operate on July 1, 1956 (except in the case of the overall gross weight of any group of two or more consecutive axles on the date of the enactment of the Federal-Aid Highway Amendments of 1974.) Prohibits the operation of such vehicles on the basis that a State law could have authorized such operation at some prior date by permit or otherwise. Declares that nothing in this Act shall be construed to prevent a State from reducing its gross vehicle weight limitation or its single or tandem axle weight limitations on the Interstate System for operations under the exception; but in no event shall such reduction fall below specified weight limits for vehicles operating on such System. Subjects all vehicles or combinations operating under the exception to routing-specific, commodity-specific, and weight-specific designations in force in a State before January 1, 1994.

(Sec. 4) Directs the Secretary of Transportation (Secretary) to determine the meaning of the term "vehicles and loads which cannot be easily dismantled or divided" (including a commodity-specific definition of such term) as it relates to provisions concerning vehicle weight limitations.

Declares that it is the policy of this Act to promote conformity with the Interstate weight limits for the benefit and safety of all motorists.

(Sec. 5) Declares that the gross vehicle weight limitations and axle loading limitations with respect to vehicles and combinations on any non-Interstate highway on the National Highway System (NHS) shall be those set by State statute as of January 1, 1994, except that those limitations applicable to non-Interstate segments not in existence upon enactment of this Act shall be the Interstate weight limits.

Directs the Secretary to determine and publish a list of: (1) the State's gross vehicle weight limitations and axle loading limitations as of January 1, 1994, with respect to non-Interstate highways on the NHS; and (2) operations not in conformance with such limitations with respect to vehicles and combinations on such highways of such State before January 1, 1994, and which were in lawful operation on a regular or periodic basis, including seasonal operations, before that date. Subjects all vehicles or combinations included on the non-conforming operations list to routing-specific, commodity-specific, and weight-specific designations in force in a State on December 31, 1993.