 The first phase, centered around a railroad overpass south of East Stanwood, was completed as scheduled in November 1962, despite part of the overpass collapsing midway through construction.The remaining highway between East Stanwood and US 99 (later rebuilt as I-5) was completed in October 1969, serving a temporary partial cloverleaf interchange until I-5 was expanded in 1972.During the 1964 highway renumbering, SSH 1Y was replaced by SR 532 and SSH 1E became SR 530.