Interstate 405 begins in Tukwila at I-5, SR 518, and Westfield Southcenter, and continues east through Renton and then turns north and runs through Bellevue, Kirkland, and Bothell, before turning northwest and crossing I-5 in Lynnwood (near Alderwood Mall), where it becomes SR 525, a freeway for its first few miles. I-405 was built in stages between 1955 and 1968, with a major upgrade north of Bellevue to Bothell in 1972. HOV lanes were added in the 1980s and 1990s, the interchange between I-405 and SR 520 was upgraded in the early 1990s, and new ramps have been added in downtown Bellevue in recent years to supplement the original interchange at NE 8th Street.