south here. At this interchange, I-75 splits off, heading north towards Lexington, Kentucky, and US 25W and SR 9 begin an unsigned concurrency with I-640. Also at this interchange, SR 9 continues onto an unsigned concurrency with US 25W north to Clinton. The highway then shifts slightly east-northeast and, a few miles later, has a partial cloverleaf interchange with US 441 (Broadway). A short distance later, I-640 crosses a Norfolk Southern Railway mainline. Some distance later, the freeway turns almost directly east. It then reaches an interchange with Washington Pike and Millertown Pike; access between the two is provided via frontage roads on both sides of the interstate. The highway then gradually shifts south and, a few miles later, crosses another Norfolk Southern mainline and US 11W (Rutledge Pike) without intersecting this route. I-640 then reaches its eastern terminus at a directional T interchange with I-40 on the eastern outskirts of Knoxville. Here, US 25W and SR 9 continue onto a brief unsigned concurrency with I-40, heading eastward toward Asheville, North Carolina. History Planning and construction The highway that is now I-640 had its origins in a plan commissioned by the city of Knoxville in 1945, which recommended that a series of expressways be constructed throughout the city to relieve traffic on surface streets. It was initially known as the Dutch Valley Loop during its planning phase and roughly followed its current alignment. Planners intended these freeways to be integrated into the then-proposed nationwide highway network that later became the Interstate Highway System, which, at the time, was expected to eventually be authorized by Congress. After the passage of the Federal Aid Highway Act of 1956, which initiated the interstate system, the highway was designated as I-640 by the American Association of State Highway Officials (AASHO) on November 12, 1958. Construction on the interchange between I-640, I-75, I-275, and US 25W began in February 1961, as part of the project to build the segment of I-75 (now I-275) directly south of this interchange, which had begun construction in March 1958. It was completed in November 1962 and dedicated on January 3, 1963. On December 4, 1964, what is now the interchange between I-40/I-75 and a short segment of I-640 extending north to SR 169 (Middlebrook Pike) was opened to traffic, providing access between both routes to local motorists. The connecting segment of I-40/I-75 was also opened to all traffic at