Whenever the construction thereof would lessen the distance between two points on separate State highway routes or traffic congestion would be relieved and the flow of traffic on State highways facilitated thereby, the Secretary of Highways, with the approval of the Governor, is hereby authorized and empowered to construct bridges over streams or over streams and the facilities of public utility companies and to construct the necessary approaches and connecting roads thereto in or between cities of the second class, second class A, and third class, boroughs, incorporated towns, or townships, or in or between any two or more of such political subdivisions, to join or connect two or more State highway routes.