Beginning at the existing elevated structure around Grand Central Terminal (East 42nd Street), the elevated highway was to continue north along Park Avenue to the Harlem River, where a new toll bridge was to be constructed. A five-cent toll on the bridge was to make the project self-liquidating. Continuing north into the Bronx, the elevated highway was to end at the intersection of Grand Concourse and East 153rd Street.
Not everyone supported the Park Avenue Express Highway. Samuel Levy, the borough president of Manhattan, strongly opposed the highway, arguing that the elevated structure would damage real estate values in the borough, much as the elevated train lines had in previous decades. He also argued that construction of the expressway would end any chance of placing the New York Central (now Metro-North) tracks below ground north of 97th Street.
The Uptown Chamber of Commerce, which represented business interests in Harlem, also opposed the highway. The business association feared that the highway would create a "Chinese wall" that would divide neighborhoods.
In 1941, the New York City Planning Department reiterated its support for the Park Avenue Express Highway as follows:
Park Avenue Express Highway: At the present time, this section of Park Avenue (north of 96th Street) is entirely inadequate to handle the large volumes of traffic using Park Avenue south of 96th Street. Construction of this project and a new Harlem River crossing, connecting with the proposed Grand Concourse Express Highway in the Bronx, would provide a much-needed northerly outlet for Park Avenue traffic. The express highway could be combined with a project for covering the railroad tracks and reclamation of slum areas. The Borough President of Manhattan has estimated that the cost of this project would be about $29,000,000.
Park Avenue-Harlem River Crossing: This would form a link between the proposed express highway on Park Avenue in Manhattan and the proposed express highway on the Grand Concourse in the Bronx. Constructed as a high-level free bridge, it would serve to eliminate traffic delays caused by frequent openings of the existing Harlem River crossings, which are all low-level bridges. The Bronx Borough President's engineers have estimated that the cost of this improvement would be $2,500,000.
REPLACING RAILS WITH ROADS UNDERGROUND: In 1956, a steel company offered its own controversial proposal to provide a north-south expressway in Manhattan. Some important facets of the "Grand Park Avenue Expressway" proposal were as follows:
The railroad tracks emanating from Grand Central Station were to be ripped out and replaced with an eight-lane expressway. The expressway would have utilized the 2½-mile underground tunnel from 42nd Street north to 97th Street, then continued north along a new viaduct north to the Major Deegan Expressway.
Grand Central Terminal was to be torn down, and replaced by a new complex with a 65-story office tower.
A new consolidated passenger and freight rail terminal was to be constructed in the Morrisiana section of the Bronx, not far from Yankee Stadium. The terminal was to be utilized by the New York Central and the New York, New Haven and Hartford railroads.
The developers of this proposal tried to justify it with the following quote: "Commodore Vanderbilt tore down and rebuilt: that is the lesson of our age." The controversy surrounding the Grand Park Avenue Expressway proposals helped shape debate on future Manhattan highways such as the Lower Manhattan and Mid-Manhattan expressways, both of which were also never built.