The proposed route, which was to begin at the intersection of the Staten Island Expressway (I-278) and the West Shore Expressways (NY 440), was to continue the route of the West Shore Expressway north for about one mile. It was to veer east along the Forest Avenue-Richmond Terrace corridor, not far from the Kill Van Kull (northern) shoreline of Staten Island. It was to turn south at the Staten Island Ferry Terminal before rejoining the Staten Island Expressway near the Verrazano-Narrows Bridge toll plaza. South of the Staten Island Expressway, the shoreline route was to continue as the Shore Front Drive, a controlled-access parkway.
Although no official designation was given to the route --neither New York State nor New York City approved the route -- Moses had a tendency to give route numbers to routes that had not yet been approved. The NY 439 designation was to be given to the North Shore Expressway, since it would have replaced the NY 439 designation given to the parallel Forest Avenue.
In 1966, the Tri-State Transportation Commission recommended that the North Shore Expressway be considered among its long-range proposals for future limited-access highways as follows:
The North Shore Expressway, a waterfront route along the periphery of Staten Island, will foster redevelopment of existing residential, commercial and industrial areas. It will improve access to the Goethals, Bayonne and Narrows bridges, as well as to the Staten Island-Manhattan Ferry.
Four years later, the expressway was adopted in the revised master plan for Staten Island. This master plan also called for a new Staten Island Rapid Transit (SIRT) route along the existing railroad right-of-way, as well as for a direct rail link to lower Manhattan.
Of all the routes planned and constructed on Staten Island, the route of the North Shore Expressway went through some of the most densely populated neighborhoods in the borough. After the experience of previous decades, Mayor John Lindsay adopted a policy that New York City would not approve construction of highways that endanger residential and commercial areas. By the early 1970's, Moses had all but lost his influence among state and city officials, except for a consulting position at the Triborough Bridge and Tunnel Authority (TBTA).