Holland Tunnel

The Holland Tunnel was the first long mechanically ventilated underwater tunnel in the world designed for motor vehicle use. Its twin tubes, each 29.5 feet in diameter and 3,500 feet long, were shield-driven by the pneumatic method through extremely difficult river-bottom conditions overcome by the ingenuity and determination of engineers Clifford M. Holland, Milton H. Freeman, and Ole Singstad. When built, the tubes were the largest in the U.S., and their unprecedented length marked a bold step forward in tunnel engineering. The principal feature of the cast iron-lined tunnel is its ventilating system, whose design was based on elaborate physiological and mechanical tests conducted mainly by the U.S. Bureau of Mines. That system, which forces fresh air in at roadway level and draws exhaust-laden air off at the ceiling over the entire tunnel length, became the model for all succeeding vehicular tunnels. Air is moved by 42 blowing fans and 42 exhaust fans with 6000 total horsepower, arranged in four ventilation buildings. The tunnel is operated by The Port Authority of New York and New Jersey.

New York, New York · United States