The Second Avenue Subway is a New York City Subway line that runs under Second Avenue on the East Side of Manhattan. The first phase of this new line, with three new stations on Manhattan's Upper East Side, opened on January 1, 2017. The full Second Avenue Line, if it will be funded, will be built in three more phases to eventually connect Harlem–125th Street in Harlem to Hanover Square in Lower Manhattan. The proposed full line would be 8.5 miles (13.7 km) and 16 stations long, serve a projected 560,000 daily riders, and cost more than $17 billion.

The Metropolitan Transportation Authority (MTA) is a public benefit corporation responsible for public transportation in the New York City metropolitan area of the U.S. state of New York. The MTA is the largest public transit authority in North America, serving 12 counties in Downstate New York, along with two counties in southwestern Connecticut under contract to the Connecticut Department of Transportation, carrying over 11 million passengers on an average weekday systemwide, and over 850,000 vehicles on its seven toll bridges and two tunnels per weekday.