In the new bridge's final configuration, the north span will carry the northbound and westbound automobile traffic of I-87 and I-287; it will also carry a shared-use path for bicycles and pedestrians. The south span will carry the southbound and eastbound automobile traffic of I-87 and I-287.
Tappan Zee Constructors began construction in 2013. The north span officially opened to westbound traffic on August 26, 2017; it also opened to eastbound traffic on October 6, 2017. Tappan Zee Constructors then began demolishing the old bridge. Eastbound traffic will be switched to the south span upon its completion. Both spans are expected to be operational by the end of 2018.
The official name of the bridge has been controversial since its announcement, with a petition and proposed legislation opposing the attachment of Mario Cuomo's name to the bridge.
The Tappan Zee river crossing was named by 17th century Dutch settlers. The Tappan Zee Bridge and the smaller Bear Mountain Bridge are the only crossings of the stretch of the Hudson between Westchester and Rockland counties, both of which are part of New York City's populous northern suburbs.
The original Tappan Zee Bridge was a cantilever bridge built from 1952 to 1955. The bridge was 3 miles (4.8 km) long and spanned the Hudson at its second-widest point. It was the longest bridge in New York State, at a length of 16,013 feet (4,881 m) including approaches. Built immediately after the Korean War, the bridge had a low construction budget of only $81 million and a designed life-span of only 50 years. During its first decade, the bridge carried fewer than 40,000 vehicles per day.