The Massachusetts Executive Office of Transportation (EOT) recognized the need to evaluate and address transportation issues in the Interstate 495 (I‑495) corridor through the Merrimack Valley Metropolitan Planning Organization and the Northern Middlesex Metropolitan Planning Organization regions of the state. This study, officially called the Interstate 495 Corridor Transportation Study, was initiated by EOT to provide a forum for state and regional agencies, municipal officials, business leaders, legislators, transportation service providers, and the general public to collaboratively develop reasonable solutions to identified existing and future transportation problems in the study area.

 

The concept of an outer loop highway for eastern Massachusetts was first announced by the Massachusetts Department of Public Works (MDPW), MassHighway’s predecessor, in the late 1940s at the same time as plans were being developed by that agency for an expressway network to serve Boston and its inner suburbs. This proposed outer loop was to be located at an approximate 30-mile radius from Boston. It would, in effect, be the third belt highway around metropolitan Boston and would supplement the “Relocated Route 128”, which was to be built to serve the towns in an inner ring at an approximate 15-mile radius from Boston, and the proposed but never built Inner Belt expressway (I‑695) in the Boston urban core. As conceived, the outer loop highway would be approximately 87 miles in length between Route 1 in Salisbury and Route 1 in Foxborough. Its purpose would be to provide an economic boost to the communities that it would serve by providing greatly improved access to all parts of the state and nation. This outer loop was initially referred to as “Relocated Route 110.” With subsequent approval from the Federal Bureau of Public Roads in 1958 for its inclusion in the new Dwight D. Eisenhower System of Interstate and Defense Highways, the proposed roadway was redesignated I‑495. Meanwhile, the MDPW was also developing plans for “Relocated Route 28” between Foxborough and the Bourne Bridge in Buzzards Bay. This latter roadway was subsequently first redesignated as Route 25. Later, in 1982, much of it became part of I‑495.

 

The very first section of what was to eventually become the complete I‑495 opened in 1959 and was a section of Route 25 roadway in Middleborough between Routes 28 and 44. Regarding the original portion of I‑495 between Salisbury and Foxborough, construction occurred in stages, with the first to be completed being that section between Exit 29 (Route 2) in Littleton and Exit 31 (Route 225) in Westford in 1961. The remaining sections of roadway in the Merrimack Valley followed in subsequent years. Specifically, the section of roadway between Exit 31 in Westford and Exit 36 (Route 3) in Chelmsford was completed in 1962, while the section between Exit 36 in Chelmsford and Exit 42 (Route 114) in North Andover was opened to traffic in1963. Next to come on line, in 1964, was the roadway section between Exit 42 in North Andover and Exit 53 (Broad Street) in Merrimac. The final section in the valley, between Exit 53 in Merrimac and I‑95 in Salisbury, opened in 1967. On the southern end of I‑495, construction progress was considerably slower. For example, the section between Exit 13 (I‑95) in Foxborough and Exit 23 (Route 9) in Westborough was completed in 1969, but it was not until 1982 that the final section of I‑495 between Exit 7 (Route 24) in Raynham and Exit 13 in Foxborough was opened to traffic.