ISTEA has created a "national highway system," consisting of the interstate highway system and other key highway links. The NHS funding category has been established to support improvement projects on this key network.

Other (OTHER)
This represents funding provided from sources other than state or federal funding. Sources could include the Port Authority of New York and New Jersey, other state agencies, private developers, counties or municipalities.

Planning (PL, PL-FTA)
This federal-aid funding category provides funds for the federally mandated transportation planning process conducted within each Metropolitan Planning Organization.