U.S. Route 1 in Massachusetts in the context of "Massachusetts Turnpike"

The Central Artery (officially the John F. Fitzgerald Expressway) is the concurrent section of Interstate 93, US 1 and Route 3 through Downtown Boston, Massachusetts, United States. The modern-day Artery, built as part of the Big Dig from 1995 until 2003, begins at the Southeast Expressway in the South End. Traveling north, it has an interchange with the east–west Massachusetts Turnpike (I-90), and travels beneath the Financial District and Government Center through the O'Neill Tunnel. Route 3 exits onto the Leverett Connector within the tunnel in Charlestown; US 1 exits aboveground from the Zakim Bridge onto the Tobin Bridge, and I-93 continues on the Northern Expressway toward New Hampshire beyond the bridge.

The original Artery, constructed in the 1950s, was named after John F. Fitzgerald; it was partly elevated and partly tunneled. Its reputation for congestion inspired the local nicknames "The Distressway," "the largest parking lot in the world", and "the other Green Monster" (the paint of the highway girders shared the same color as the left field wall at Fenway Park). The original Artery was demolished after the O'Neill Tunnel was completed, and was replaced with the Rose Fitzgerald Kennedy Greenway, named after the daughter of John F. Fitzgerald and the mother of John F. Kennedy.

The Thomas P. "Tip" O'Neill Jr. Tunnel (colloquially O'Neill Tunnel) is a highway tunnel built as part of the Big Dig in Boston, Massachusetts. It carries the Central Artery underneath downtown Boston, and is numbered as Interstate 93 (I-93), U.S. Route 1 (US 1), and Route 3. It roughly follows the route of the old elevated Central Artery, though the northbound entrance, at the corner of Kneeland Street and Atlantic Avenue, is somewhat east of the southbound exit (at Kneeland and Albany streets) to allow for a reconfigured interchange with the Massachusetts Turnpike. It runs from the Zakim Bunker Hill Bridge at its north portal—barely 165 feet (50 m) east of the TD Garden sports facility's eastern corner—to Boston's Chinatown at its south portal. The tunnel is named for Tip O'Neill, former Speaker of the United States House of Representatives, whose constituency included several of the surrounding communities in Metro Boston.