Transportation in Boston includes roadway, subway, regional rail, air, and sea options for passenger and freight transit in Boston, Massachusetts. The Massachusetts Port Authority (Massport) operates the Port of Boston, which includes a container shipping facility in South Boston, and Logan International Airport, in East Boston. The Massachusetts Bay Transportation Authority (MBTA) operates bus, subway, short-distance rail, and water ferry passenger services throughout the city and region. Amtrak operates passenger rail service to and from major Northeastern cities, and a major bus terminal at South Station is served by varied intercity bus companies. The city is bisected by major highways I-90 and I-93, the intersection of which has undergone a major renovation, nicknamed the Big Dig. Road transportation Road infrastructure Except for the Back Bay and part of the South Boston neighborhoods, Boston has no street grid. The City of Boston, composed of many smaller towns annexed over the years, retained most of the pre-existing street names, resulting in many duplicates throughout the city. Expressways and freeways in and around Greater Boston are laid out with two circumferential expressways: Interstate 495 and Route 128. The circumferential routes are bisected by several radial highways, including: Interstate 93 (the Northern/Southeast Expressway), which extends north of the city into New Hampshire, and southward to the Braintree Split, Interstate 90 (the Massachusetts Turnpike), connecting Boston with Worcester and Springfield, United States Route 1 (the Northeast Expressway/Newburyport Turnpike), crossing the Tobin Bridge and eventually serving Newburyport, Storrow Drive, an unnumbered high-speed parkway along the Charles River connecting downtown Boston with the Route 2 corridor, U.S. Route 20, a route running from Kenmore Square to Newport, Oregon — although it is not an expressway. Massachusetts Route 2 (the Concord Turnpike/Alewife Brook Parkway), serving the northwestern suburbs including Lexington, Concord and Fitchburg, Massachusetts Route 3 (the Pilgrims Highway), connecting Boston with Cape Cod, United States Route 3 (the Northwest Expressway), a functionally separate highway serving Lowell, Burlington and other suburbs in between Route 2 and I-93, Massachusetts Route 24, serving the interior southern suburbs, including Brockton, Taunton and Fall River and Interstate 95, indirectly connecting Boston with Rhode Island via I-93. By the early 1990s, traffic on the elevated downtown portions of I-93 and Route 1 (the Central Artery) was 190,000 vehicles per day, with an accident rate four times the national average for urban interstates. Traffic was bumper-to-bumper for six to eight hours per day, with