Ole Knutsen Singstad (June 29, 1882 – December 8, 1969) was a Norwegian-American civil engineer best known for his work on underwater vehicular tunnels in New York City. Singstad designed the ventilation system for the Holland Tunnel, which subsequently became commonly used in other automotive tunnels, and advanced the use of the immersed tube method of underwater vehicular tunnel building, a system of constructing the tunnels with prefabricated sections. He also designed the Lincoln Tunnel, Brooklyn–Battery Tunnel, and Queens–Midtown Tunnel. By 1950, Singstad had designed and overseen the construction of more underwater tunnels than all other engineers combined. In 1946, the Triborough Bridge Authority under Robert Moses took over tunnel construction in New York, and Singstad was subsequently sidelined as Moses favored bridges over tunnels. Early life Ole Singstad was born at Singstad farm in Lensvik (now Orkland municipality) in Trøndelag county, Norway. He was the seventh of nine children born to Knut Jacobsen Singstad (17 May 1831 – 24 November 1906) and Anne Mikkelsdatter Auset Singstad (10 July 1843 – 30 April 1947). In 1898, Singstad attended grammar school in Ålesund. Later, his sister Marie, a midwife, encouraged Singstad to further his education. He studied in Trondheim at the Trondheim Technical School from 1901 to 1905, where he was chairman of the student body. In 1905, he emigrated to the United States. He became a U.S. citizen in 1911. Career Early work Ole Singstad first worked for the Central Railroad of New Jersey. In 1907, he moved to Norfolk, Virginia, where he worked on railroads and bridges for the Virginian Railway. He returned to New York City and worked at the Hudson and Manhattan Railroad, designing tunnels under the Hudson River in 1909–1910, and later spent seven years in charge of work on subways and rail tunnels in Manhattan, Brooklyn, and under the East River. During this time he worked with Clifford Holland for the New York Public Service Commission of the first district of New York. In 1917–1918, Singstad worked at the Chile Exploration Company, and in 1918–1919, he worked with Barclay, Parsons, and Klapp (now Parsons Brinckerhoff), where he was in charge of designing a rapid-transit system for Philadelphia, and made preliminary designs for a vehicular tunnel under the Delaware River. New York City tunnels Singstad is widely known for work on the underwater road tunnels in New York City and for designing the ventilation system that