= The original plan for Interstate 91—detailed in the 1953 Master Highway Plan for the Springfield, Massachusetts, Metropolitan Area—called for Interstate 91 to occupy an enlarged U.S. Route 5 in West Springfield—the route which had, historically, been used to reach West Springfield and Springfield from both the north and the south.

Between 1953 and 1958, Riverdale Road was widened in places, added on to, and numerous businesses were closed and moved back, or to other parts of West Springfield to make way for Interstate 91, which was planned to connect with Springfield via numerous bridges. The original plan for I-91 would have likely benefitted West Springfield, which already had U.S.

5 passing through, causing travelers to patronize many of West Springfield's businesses. In 1958, however, Springfield's city planners campaigned vociferously for Interstate 91 to occupy Springfield's riverfront. Their reasoning at the time was that Springfield, being a more populous city than West Springfield, should have a major highway routed through it.

Indeed, Springfield's 1958 city planners advocated that the construction of I-91 on Springfield's riverfront would catalyze economic growth comparable to that experienced during the great railroad expansion of the mid-19th century.Although West Springfield had a right and legal claim to Interstate 91, Massachusetts highway officials relented to Springfield's intense pressure when confronted with a technicality: a short, existing section of US 5 through West Springfield that was built in 1952–1953 failed to meet Interstate design standards.

Thus the plans for I-91 in West Springfield were shelved, and moved to the east bank of the river in Springfield, where an elevated highway was designed (as opposed to the planned ground-grade highway in West Springfield.) After Interstate 91 was constructed in Springfield, that city did not experience anything like the prosperity boom predicted by its city planners in 1958.

I-91's construction in Springfield coincided with the beginning of that city's four decades of decline. Unlike West Springfield's U.S. 5, Springfield's I-91 was constructed in an area where there had never been highway traffic or businesses that catered to such traffic. Due to I-91's proximity to both Springfield's densely built downtown and the city's riverfront, there has never been enough space in Springfield to build more than a few of these businesses.

Thus Springfield never received the economic benefit that it expected from I-91 – and which, according to recent academic assessments by the UMass School of Urban Design, West Springfield would have.