Maps and History at BOSTONROADS

BOSTON 1937: Through this map scan, Paul Schlichtman, webmaster of "The Roads of Massachusetts" web site, shows the road network from 1937.
MAP 1: Metropolitan Boston (165K)

In 1948, the Massachusetts Department of Public Works released the Master Highway Plan for Metropolitan Boston, which guided expressway construction in the Boston area for nearly a quarter century.
PART 1: Text of "Master Highway Plan"
PART 2: Map of Proposed Expressways in the Boston Area (410 K)

From 1965 to 1968, the Massachusetts Department of Public Works and the city of Boston developed a regional plan that included proposals for a number of approved (but unbuilt) expressways.
MAP 1: Boston and Immediate Vicinity (82 K; courtesy Stuart Brorson)
MAP 2:
Metropolitan Boston (including Route 128) (57 K; courtesy Stuart Brorson)
MAP 3: Metropolitan Boston (outside Route 128) (764 K)

In "Boston's Canceled Highways," Scott Moore (of the "New England Transportation" web site) profiles some of the unbuilt highways in the Boston area. Particular emphasis is paid to the unbuilt Inner Belt (I-695).