Roosevelt Island Bridge
This vertical-lift bridge was constructed between 1952 and 1955 and is 2,877 feet long with a 1,000-ton lift span of 418 feet and 170-foot high towers. The lift section is raised with 48 200-ton cables offset by concrete counterweights. Clearance is 40 feet over mean high water, increasing to 100 feet when the span is lifted.
From the earliest days of the island, access had been limited to ferrys until a four-cab elevator building was built to connect with the Queensboro Bridge in 1930. Increasing traffic needs and congestion on the Queensboro Bridge necessitated construction of this separate bridge, although there was initial opposition in the City Council over whether the amount of traffic justified the $6.5 million cost. (reference)