State Route 523 (SR 523) begins at an intersection with SR 99 and North 145th Street at the northern Seattle and southern Shoreline city limits;[4] at the SR 99 intersection, the highway is named 145th Street.[1] From its western terminus, the roadway travels east to 1st Avenue NE, where SR 523 becomes Northeast 145th Street, which the road keeps until its eastern terminus.[1] The highway travels 0.20 miles (0.32 km) east to interchange with Interstate 5 (I-5), where the northbound ramps are accessed through nearby 5th Avenue Northeast.[1][5] After the I-5 interchange, the road forms the northern boundary of the Jackson Park Golf Course and later continues to SR 522 at the northern Seattle, southern Shoreline and western Lake Forest Park city limits.[4][6] The SR 523 / I-5 interchange was used by an estimated 28,000 motorists daily based on annual average daily traffic (AADT) data collected by the Washington State Department of Transportation.[7]
History
145th Street was paved by the King County government between 1934 and 1935.[8] The Washington State Legislature first established a state-maintained highway on a section of present-day SR 523 in 1937, with the establishment of Secondary State Highway 1J (SSH 1J), which ran from Downtown Seattle to Primary State Highway 1 (PSH 1) in North Seattle, via the current 0.05-mile (0.08 km) long section of SR 523 from I-5 to 5th Avenue Northeast.[1][9] During the 1964 highway renumbering, SSH 1J became SR 513 and PSH 1 became I-5;[10] the northern terminus of SR 513 became the current SR 523 / I-5 interchange.[11] In 1991, the northern terminus of SR 513 was moved south to its current location, Magnuson Park and SR 523 was established.[2][3]
^Washington State Legislature (March 18, 1937). "Chapter 207: Classification of Public Highways". Session Laws of the State of Washington (1937 ed.). Olympia, Washington: Washington State Legislature. p. 996. Retrieved June 12, 2009. (j) Secondary State Highway No. 1J; beginning at a junction with Primary State Highway No. 1 in the vicinity north of Seattle, thence in an easterly direction by the most feasible route to the vicinity of Lake Washington, thence in a southeasterly direction by the most feasible route to Seattle in the vicinity of the Naval Air Station at Sandpoint.