 The city got a boost in the 1940s and 1950s from heavy automobile traffic along US-27, which was a primary route connecting the Great Lakes region with Florida before I-75 was completed.The routing of Interstate 40 through southwestern Harriman connected the community more closely with Knoxville but never produced the kind of modern industrial development inside the town that community leaders expected.The city, still quaint but clearly different now from its economic heyday, still shows considerable evidence of being a "planned community".