Interstate 275 (Tennessee)

Interstate 275 (I-275) is an Interstate Highway in Tennessee that serves Knoxville by connecting the downtown with I-75/I-640/US Route 25W (US 25W). Measuring 2.98 mi in length, it runs from a northern terminus at the junction with I-75/I-640/US 25W to a southern terminus at I-40. I-275 was formerly a section of I-75, which was rerouted onto I-640 in 1980 after a section of that route was completed.

Route description
I-275 begins at a complicated interchange with I-40 in Downtown Knoxville. US 441 southbound (Henley Street), State Route 62 (SR 62, Western Avenue), and 11th Street are also directly accessible from I-275 southbound at this interchange, and northbound I-275 is directly accessible from US 441 northbound and SR 62 here. About 0.6 mi north of this point, I-275 has an interchange with Baxter Avenue and then Woodland Avenue about 0.35 mi later. The route then curves sharply to the northwest and then sharply to the northeast about 0.4 mi later and crosses a railroad before reaching an interchange with Heiskell Avenue about 0.6 mi later. Passing through Sharp's Gap, a low point in Sharp's Ridge, I-275 reaches its northern terminus with I-75, I-640, and US 25W about 0.75 mi later. At this interchange, the route crosses I-640, and continues north as I-75. US 25W northbound is accessible from a flyover ramp that splits off from I-275 northbound about 0.1 mi south of I-640.

History
The freeway that is now I-275 was first planned in the 1940s as part of a series of freeways for the city of Knoxville and was known initially as the North–South Expressway. The route was integrated into the Interstate System as part of I-75, and the southern terminus was the end of a concurrency with I-40 and I-75. Work on most of the route began in March 1958, and the first section, located between I-40 and Baxter Avenue, opened on October 28, 1960, after several delays. The final section, located between Oldham Avenue and Heiskell Avenue, opened on January 24, 1962. A dedication ceremony for this section took place on February 9, 1962.

On December 6, 1979, TDOT submitted an application to the American Association of State Highway and Transportation Officials (AASHTO), requesting relocation of I-75 onto the then-underconstruction western leg of I-640 and renumbering of the route between I-40 and I-640/I-75 as I-275. The application cited the shorter distance and fewer number of interchanges that through traffic on I-75 would be required to traverse. The change was also intended to divert through traffic away from traffic generated by the 1982 World's Fair. AASHTO approved this redesignation on June 22, 1980. Signs for I-275 were posted on December 17, 1980, and the western leg of I-640 was opened to traffic six days later.

Between December 1, 2006, and January 26, 2008, the existing cloverleaf exits (1A–B, 1C–D, 2A–B) were replaced with traditional diamond interchanges to add a continuous third lane in each direction. This was done to handle increased traffic flow for the shutdown of I-40 in Downtown Knoxville that took place on May 1, 2008. I-275 was the designated detour route for I-75 northbound traffic during the I-40 shutdown to avoid traffic congestion at the I-75/I-640/I-275/US 25W junction as the ramp for I-75 northbound from I-640 eastbound is only one lane.