Автомагистраль SR 599 в штате Вашингтон

State highway in Washington

State Route 599 (SR 599) is a state highway and freeway in King County, Washington, United States. It is located entirely within the city of Tukwila and travels 1.75 mile (3 km) northwest along the Duwamish River between junctions with Interstate 5 (I 5) and SR 99. The freeway has one intermediate exit and follows the Central Link light rail line.

SR 599 is 1.75 mile (3 km) long and travels on a four lane freeway located entirely within the city of Tukwila in suburban King County. The only intermediate junction on SR 599 is a partial cloverleaf interchange at South 133rd Street near several office parks, including the headquarters of BECU. The freeway then travels northwest, following the elevated Central Link light rail tracks to the west and the Duwamish River and the Green River Trail to the east. SR 599 then turns west to travel around a King County Metro bus base, which has a direct onramp to the southbound freeway, SR 99 continues northwest along the freeway and into Seattle on West Marginal Way. WSDOT conducts an annual survey of average traffic volume on the state highway system that is measured in terms of annual average daily traffic, finding in 2016 that approximately 44,000 vehicles use SR 599.

SR 599 became a state highway in 1971, but had been part of Washington's older highway system (Primary and Secondary Highways) from 1957 to 1970. The highway, then known as PSH 1 WM, or West Marginal Branch, U. S. Route 99 (US 99) was about to be removed from the system, so when I 5 was completed up to Tukwila, US 99 switched to the route of SR 599. Later on, the current route of SR 599 became known as US 99T (Temporary) and later SR 99T in 1964. In 1971, the highway became SR 599.