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.