sections of the corridor were renumbered to SR 405. By 1966, the remaining sections of SR 405 were fully renumbered to I-405. The first segment of the Renton Freeway to be completed was between Tukwila and Renton, costing $12.6 million and opening to traffic on August 31, 1965. An extension that bypassed downtown Renton opened on September 3, connecting with the existing freeway to Kennydale. A four-lane section of I-405 between Kennydale and Factoria in southern Bellevue was opened to traffic in August of that year. A temporary overpass with a traffic signal was installed at the Factoria interchange while construction continued on a new connection to US 10 (later I-90) for several more years. The interchange with I-5 at Tukwila opened in stages between February and November 1967; it cost $16 million to construct and included ramps to the new Southcenter shopping mall. The final section of I-405 to be built, between Woodinville and Lynnwood, was opened to traffic in November 1969. Further construction expanded I-405 to six lanes, including a section near Woodinville that involved the demolition of recent bridges that were too narrow to support three lanes per direction. These projects had been delayed due to a cut in federal highway spending in the late 1960s. The proposed route between Bothell and Lynnwood was originally planned to follow Swamp Creek from Kenmore, but was later moved further northeast to North Creek after opposition from residents. It was later revived in 1971 as part of a shorter connector between Kenmore and I-405 that was rejected for a lack of projected need. Later development In the 1960s, the state government studied the construction of an outer freeway bypass due to expected traffic demand on I-405. A report released in 1970 concluded that the outer bypass, nicknamed I-605, would not be necessary and recommended expanding I-405 to eight lanes in some sections. The proposal had also been controversial with residents around Lake Sammamish, around which the freeway corridor was moved several times. One of the major construction projects on the highway was straightening the s-curves in Renton, which were designed for speeds of up to . This project began in 1990, and was estimated to cost $70 million. Also during this time the portion of the highway between I-5 and South Renton was being repaved and HOV lanes were being added. 21st century Originally intended as a bypass to I-5