| Braintree Split | |
|---|---|
 Aerial image of the Braintree Split in 2019 | |
 Interactive map of Braintree Split | |
| Location | |
| Braintree–Quincy, Massachusetts | |
| Coordinates | 42°13′37″N71°01′16″W / 42.227°N 71.021°W /42.227; -71.021 |
| Roads at junction | |
| Construction | |
| Type | Full Y |
| Maintained by | Massachusetts Department of Transportation |
TheBraintree Split is the major interchange ofInterstate 93 (I-93),U.S. Route 1 (US 1), andRoute 3 inBraintree, Massachusetts, one of theSouth Shore suburbs ofBoston. Traveling northbound, the routes merge into a three-wayconcurrency towardsBoston. Traveling southbound, they divide into the concurrent I-93 and US 1 towardssoutheastern Massachusetts, and Route 3 towardsCape Cod.
The split is located close to the border between Braintree andQuincy. It was previously the southern terminus ofRoute 128, the mainbeltway aroundBoston; it shared the roadbed with I-93 and US 1 traveling towards the split before they join with Route 3. It was truncated to the junction of I-93 andI-95 inCanton in 1997; despite no longer carrying this designation, the split continues to be informally recognized as the starting point of Route 128 within Massachusetts.[1]
The Braintree Split is used as a focal point in local radio and television traffic reports.[2] In 2006, weekday traffic volume through the interchange averaged 250,000 to 275,000 vehicles daily.[3]
The Braintree Split, technically a "Directional T" type of interchange, is the main road gateway to theSouth Shore region ofMassachusetts, making it a critical point inBoston's highway system. TheSoutheast Expressway is the single limited access highway traveling south out of Boston, carrying traffic from the city destined for communities in populousNorfolk (659,909 residents)[4] andPlymouth (492,066 residents)[4] counties, partly due to the 1973 cancellation of the plannedSouthwest Corridor alignment ofInterstate 95 into Boston. Drivers other than those headed for parts ofMilton and Quincy which straddle the Expressway traverse the split to connect with Route 3 andRoute 24 traveling to the more southern localities. Similarly, Boston traffic bound for cities and towns insoutheastern Massachusetts including western Norfolk andBristol County (545,823 residents)[4] and inRhode Island negotiate the Braintree Split prior to continuing along Route 24 orInterstate 95. Finally, Route 3 serves as the primary freeway route toCape Cod from Boston's Inner Core. Travelers headed north from these destinations into Boston via I-93 north, or the inland southern and western suburbs via I-93 south,[5] likewise encounter the interchange in Braintree.
Factors local to the Braintree Split contribute to chronic congestion at the interchange.[3] The split is bordered on the south bySouth Shore Plaza, a major regional shopping mall. It is adjacent to the I-93 intersection withRoute 37/Granite Street in Braintree which feeds retail, lodging, manufacturing and office complexes along Wood Road and Forbes Road, which run parallel to the north and south lanes of I-93 west of the split. The Crown Colony office complex inSouth Quincy and office buildings on Willard Street, the northern continuation of Route 37/Granite Street intoWest Quincy, are also accessed from the south via ramps at or next to the split. Short weaves, lane drops and line-of-sight problems all contribute to congestion in the interchange and the highways it serves.[3] In addition to these issues, the split also serves theQuincy Adams subway station and Burgin Parkway, a major route into downtown Quincy, through ramps exiting the directional ramps for each roadway.
