Interstate 640 | ||||
|---|---|---|---|---|
 I-640 highlighted in red | ||||
| Route information | ||||
| Auxiliary route of I-40 | ||||
| Maintained by TDOT | ||||
| Length | 10.80 mi[1] (17.38 km) | |||
| Existed | November 12, 1958[2]–present | |||
| History | Completed in 1982 | |||
| NHS | Entire route | |||
| Major junctions | ||||
| West end |   I-40 / I-75 in Knoxville | |||
| East end |  I-40 / US 25W in Knoxville | |||
| Location | ||||
| Country | United States | |||
| State | Tennessee | |||
| Counties | Knox | |||
| Highway system | ||||
| ||||
Interstate 640 (I-640) is an east–west auxiliary Interstate Highway in Knoxville, Tennessee. It serves as a bypass for I-40 around Downtown Knoxville and is also an alternative route for traffic passing between I-40 and I-75. All trucks carrying hazardous cargo through Knoxville are required to use I-640. It has a total length of 10.80 miles (17.38 km) and runs approximately three miles (4.8 km) north of downtown through the northern neighborhoods of Knoxville.[1]
For its first 3 miles (4.8 km), I-640 has a concurrency with I-75, although exits along this segment are numbered according to the former's mileage. For the rest of its length, the Interstate maintains an unsigned concurrency with U.S. Route 25W (US 25W). Both of these highways were rerouted from their original alignments upon I-640's completion.
The route that is now I-640 was first planned by the city of Knoxville in 1945 and initiated by the Federal Aid Highway Act of 1956, along with most of the Interstate Highway System. Initial construction work began in the early 1960s, and for many years, only two miles (3.2 km) of the highway was open to traffic. Work on the remainder of I-640 began in 1977, and the last section was completed in 1982.