The National Highway System (NHS) is a network of strategic highways within the United States, including the Interstate Highway System and other roads serving major airports, ports, military bases, rail or truck terminals, railway stations, pipeline terminals and other strategic transport facilities. Altogether, it constitutes the largest highway system in the world. Individual states are encouraged to focus federal funds on improving the efficiency and safety of this network. The roads within the system were identified by the United States Department of Transportation (USDOT) in cooperation with the states, local officials, and metropolitan planning organizations (MPOs) and approved by the United States Congress in 1995. Legislation The Intermodal Surface Transportation Efficiency Act (ISTEA) in 1991 established certain key routes such as the Interstate Highway System, be included. The act provided a framework to develop a National Intermodal Transportation System which "consists of all forms of transportation in a unified, interconnected manner, including the transportation systems of the future, to reduce energy consumption and air pollution while promoting economic development and supporting the Nation's preeminent position in international commerce". The National Highway System Designation Act of 1995 (, ) is a United States Act of Congress that was signed into law by President Bill Clinton on November 28, 1995. The legislation designated about of roads, including the Interstate Highway System, as the NHS. Aside from designating the system, the act served several other purposes, including restoring $5.4 billion in funding to state highway departments, giving Congress the power to prioritize highway system projects, repealing all federal speed limit controls, and prohibits the federal government from requiring states to use federal-aid highway funds to convert existing signs or purchase new signs with metric units. The act also created a State Infrastructure Bank pilot program. Ten states were chosen in 1996 for this new method of road financing. These banks would lend money like regular banks, with funding coming from the federal government or the private sector, and they would be repaid through such means as highway tolls or taxes. In 1997, 28 more states asked to be part of the program. Ohio was the first state to use a state infrastructure bank to start building a road. An advantage of this method was completing projects faster; state laws and the lack of appropriate projects were potential problems. Overview According to the Federal Highway Administration, the National Highway System includes roads important to