(a) When the construction of sections of the parkway road parallel to existing highways will result in unnecessary expense and the United States Secretary of the Interior may, in his or her discretion, use existing or projected sections of streets or highways, bridges, parks, or other areas as connecting links between other sections of this parkway, and federal funds may be expended for parkway purposes thereon under the provisions of this subchapter, no parkway area credits need be allowed the state.
(b) In the event it is determined that the connecting links of highways should provide for other than passenger car traffic, a cooperative agreement with respect to use and the reconstruction, maintenance, and control thereof may be entered into by the United States Secretary of the Interior with the Arkansas Department of Transportation or local public authorities concerned.