Interstate 495 is an auxiliary route of I-95 in the U.S. state of Massachusetts, maintained by the Massachusetts Department of Transportation. Spanning, it is the second-longest auxiliary route in the Interstate Highway System, ranking behind I-476 in Pennsylvania by a difference of roughly. Serving as one of two beltways that forms a semicircle around Boston, and being the "outer" beltway, I-495 has its northern terminus in Salisbury, where it splits from I-95. Its route forms an arc with an approximately radius around the city, and intersects seven additional radial expressways: I-93, U.S. Route 3, Route 2, I-290, I-90, Route 24, and I-95 once more. I-495 has its southern terminus in Wareham, at the meeting of I-195 and Route 25. Originally, the stretch from Route 24 to I-195 was signed as Route 25, that status now only begins east of I-195. I-495 and areas to its immediate west are often regarded as the outermost boundary of the Greater Boston region. The freeway's northern segment parallels the New Hampshire border, at one point coming as close as of the boundary, and its southern end is roughly 10 miles north of Cape Cod. West of I-495 is the Worcester area and Central Massachusetts. The stretch of I-495 north and east of Route 2 until its terminus at I-95 in Salisbury is also the main thoroughfare connecting the communities of the Merrimack Valley region, separate from its purpose as a beltway around Boston.
Route description
Interstate 495 begins as the direct continuation of Route 25 at the intersection with Interstate 195 in West Wareham. It starts as a two-lane highway in both directions. It gets the third lane during the interchange with Route 24. The junction includes the unusual transition of shrinking from the six-lane Route 25 to the four-lane interstate, due to the third lane of Route 25 joining to and from I-195. The road heads roughly northwest, passing through the towns of Rochester and Middleborough as a four-lane highway before entering Bristol County, crossing the Taunton River at Raynham. There, it becomes a six-lane highway just southeast of the Route 24 interchange. The road continues northwest through Taunton and Norton before entering Mansfield, where there is a short collector-distributor road concurrency with Route 140. Interstate 495 makes its southern junction with its parent route, Interstate 95on the border between Mansfield in Bristol County and Foxborough in Norfolk County. The road continues through Plainville and Wrentham. The highway comes within 2 miles of the Rhode Islandstate line before turning in a more northerly direction through Franklin and Bellingham. Interstate 495 passes through Milford, Medway and Hopkinton, Westborough. Southborough, Marlborough, Hudson, Berlin, Bolton and Harvard. Continuing to turn to a more easterly direction, the road passes through Boxborough, Littleton, Westford and Chelmsford. At the Chelmsford-Lowell line lies the intersection with U.S. Route 3 and the Lowell Connector. The road continues through Lowell and Tewksbury before entering Essex County at Andover, directly at exit 39. In Andover, the road has a junction with Interstate 93. It then enters the city ofLawrence, where the road turns due north, crossing the Shawsheen River into North Andover before crossing the Merrimack River at the O'Reilly Bridge back into Lawrence. It then heads into Methuen, where the road turns back to a northeasterly route after the junction with the Loop Connector. The road heads into Haverhill, crossing the Merrimack twice more at a bend in the Bradford section of town. It passes north of downtown Haverhill, coming within 150 yards of the New Hampshire state line, the closest the road comes to leaving the state. Interstate 495 then passes through the towns of Merrimac and Amesbury before entering Salisbury where it immediately meets Interstate 95 and ends approximately south of where that interstate enters New Hampshire. Throughout its path, the road passes closely to several existing state highways. From Wareham through to the Middleborough Rotary, it parallels Route 28. For much of the stretch between Norton and Milford, the road is within a few miles of Route 140, with two junctions of that highway in Mansfield and Franklin. From Milford to Bolton, the road passes just west of Route 85. Much of the northern third of the route also roughly parallels Massachusetts Route 110.
History
As early as the late 1940s, a plan was developing for an "outer circumferential highway" around Boston, a limited-access freeway of meant to have an approximate 30 mile radius from the Boston city center. A portion of this new "outer circumferential highway" southeast of the US Route 1 junction in Foxborough was meant to be a "relocation" of the existing MA Route 28, which was quickly changed in 1947 to a new designation of Route 25 as a full-length freeway from MA 24 expwy in Raynham to Wareham. The section of I-495 between MA 24 in Raynham and I-95 at the Foxborough/Mansfield line was not constructed until the late seventies with construction beginning at I-95 in 1976 and reaching the MA 25/MA 24 interchange in 1982.. MA 25 was constructed in stages from the late 1950s to the late 1960s.
Future
In 2014, a new ITS system was installed to help commuters and the state better understand the traffic congestion on I-495. Some improvements expected to come to I-495 in the next few years include a project that will install fiber optic cable, traffic cameras and VMS Signs on I-495 from I-90 to I-93. In 2015, the state pledged $165–285 million for improvements to the Interstate 495-Massachusetts Turnpike intersection, and is considering three different plans. The work is expected to begin in 2021 and be completed in 2025. Improvements to the 495-Route 9 intersection will commence at the same duration, with a different budget.
Exit list
Interchanges were to be renumbered to mileage-based numbers under a project scheduled to start in 2016, however this project was indefinitely postponed by the MassDOT until November 18, 2019, when the MassDOT confirmed that, beginning in late summer 2020, the exit renumbering project will begin.
