Chronology

1948:
Mass DPW Commissioner William F. Callahan proposes a “Belt Route,” a multi-lane loop route around Boston, aimed at eliminating some 15,000 daily trips through “antiquated” local streets.
The Inner Belt portion would be a 7.3-mile loop from an interchange near Mass Ave and Southampton Street across Roxbury and the Charles River through Cambridge with an interchange at Mass Ave and through Somerville to an interchage at I-93.

1955:
Federal Bureau of Public Roads includes Inner Belt loop in preliminary plans for a national interstate highway network. Estimated cost: $44 million with 90% federal reimbursement.
New routing crosses Roxbury along Ruggles Street, crossing Charles River by bridge or tunnel; through Cambridge west of Brookline Street to Central Square, then along Elm Street to  Somerville line then on to I-93.

Early 1960s:
Opposition grows as land-takings begin in Roxbury and panic sales occur along Brookline Street in Cambridge.
Key political figures include Fred Salvucci, transportation advisor to Mayor Kevin White, and US Representative “Tip” O’Neill. O’Neill calls it “a China Wall” in a critical letter to the Federal Highway Administrator. Neighborhood opponents, including Cambridgeport residents and parish priests, organize. MIT joins opponents as new route blocks its future development.

1970:
Former governor John Volpe, now President Nixon’s Transportation Secretary, urges a more balanced national transportation policy, including a transfer of highway funds to mass transit.
February: Then-Governor Frank Sargent orders a moratorium on all new expressway construction work inside Route 128. Future plans, Sargent writes, “will be based on not where expressways should be built, but whether expressways should be built.”

1971:
December: Gov. Sargent cancels proposed I-695 from the Mass Pike to I-93 and segments in Cambridge and Somerville.

1972:
November: Gov. Sargent eliminates the entire Inner Belt system from further consideration

Reminder monuments on today’s landscape:
Melnea Cass Boulevard along right-of-way through Roxbury.
Unfinished exit ramps on I-93 in Somerville.
Interchange at Exit 18 (Mass Ave) on SE Expressway.
Southwest Corridor Park and Bike Route through Roxbury.
Inner Belt Road along proposed route in Somerville.
Auburn Park housing along Brookline Street.