In 1974, I-95 was canceled through Boston (cancelling its approach from Providence, Rhode Island through the Southwest Corridor) and was instead rerouted around the city using part of Route 128. US 1 was realigned to use the Tobin Bridge and Northeast Expressway, which had been signed as part of I-95; thus US 1 used the Artery north of Storrow Drive. The former alignment of US 1 from Storrow Drive south along the Artery to the Sumner Tunnel became an extended 1A, and I-93 was extended south from Charlestown along the Artery, Southeast Expressway and Route 128 from Braintree to Canton. In 1989, US 1 was moved off the MDC Parkways onto its current alignment along the full Artery. Route 1A was then truncated to the Sumner Tunnel interchange.
