sentences:  Curving slightly to the west and then again to the east, I-75 reaches an interchange with I-40 westbound about three miles later, where it begins a concurrency with I-40.About 20 miles west southwest of Knoxville, the concurrent routes widen to six lanes and cross into Knox County less than a mile later.Running approximately east northeast the two interstates pass through the western suburbs of Knoxville including Farragut and West Knoxville.