The Pacific Highway, later numbered to State Road 1 in 1923 and part of U.S. Route 99 in 1926, remained on the Bothell route until the completion of a straighter north–south highway to the west in 1927. The Bothell–Everett highway was incorporated into part of SSH 2A in 1937, forming a continuous route between Renton and Everett via the Eastside. SSH 2A was later truncated to Bothell in 1943, removing the Snohomish County section, but it was returned to the state highway system in 1957 as the newly-created SSH 2J. SSH 2J was renumbered to SR 527 in 1964 as part of a new numbering system implemented by the state government, which today forms the modern state highway system. It connected SR 522 in downtown Bothell to the Broadway Interchange in southern Everett, built in 1969 to connect I-5, US 99 (which was replaced by SR 99 in 1971), and SR 526. The highway's interchange with I-405 in northern Bothell was opened to traffic in November 1969.