The first Hudson River vehicular crossing, the Holland Tunnel connects Canal Street in Manhattan with 12th and 14th streets in Jersey City, NJ, and is considered an outstanding engineering achievement. As a tribute, it bears the name of its first chief engineer, Clifford M. Holland, who with his team surmounted many previously unsolved tunnel engineering problems. Unfortunately, Holland died before the tunnel's completion, and his successor, Milton Freeman, died five months later. The tunnel was finished under the leadership of the project's third chief engineer, Ole Singstad.
One of the most significant challenges was how to ventilate the 1.6-mile tunnel. With the dawn of the automobile age, it was imperative to find a way to remove potentially dangerous automobile fumes. Singstad's solution was to design a circular tunnel with an automatic ventilation system. Four ventilation buildings, two on each side of the Hudson River, house 84 immense fans that provide a change of air every 90 seconds, keeping air quality well within established safety limits. This innovation made the Holland Tunnel the first mechanically ventilated underwater vehicular tunnel. The methods used to design and build it still form the basis for the construction of many underwater vehicular tunnels throughout the world.
In 1984, because of its valuable contribution to tunnel design and construction, the Holland Tunnel was designated a National Historic Civil and Mechanical Engineering Landmark by the American Society of Civil and Mechanical Engineers. And in 1993, it was designated a National Historic Landmark by the U.S. Department of the Interior.
Average daily traffic is 90,000 vehicles.