Interstate 640 (I-640) is an east–west
auxiliary Interstate Highway
Auxiliary Interstate Highways (also called three-digit Interstate Highways) are a subset of highways within the United States' Interstate Highway System. The 323 auxiliary routes generally fall into three types: spur routes, which connect to or i ...
in
Knoxville, Tennessee
Knoxville is a city in Knox County, Tennessee, United States, and its county seat. It is located on the Tennessee River and had a population of 190,740 at the 2020 United States census. It is the largest city in the East Tennessee Grand Division ...
. 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
Interstate 75 (I-75) is a major north–south Interstate Highway System, Interstate Highway in the Great Lakes region, Great Lakes and Southeastern United States, Southeastern regions of the United States. As with most Interstates that end ...
. All trucks carrying
hazardous cargo through Knoxville are required to use I-640. It has a total length of and runs approximately north of downtown through the northern neighborhoods of Knoxville.
[
For its first , 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
The Federal-Aid Highway Act of 1956, also known as the National Interstate and Defense Highways Act, was enacted on June 29, 1956, when President Dwight D. Eisenhower signed the bill into law. With an original authorization of $25 billion (e ...
, along with most of the Interstate Highway System
The Dwight D. Eisenhower National System of Interstate and Defense Highways, commonly known as the Interstate Highway System, or the Eisenhower Interstate System, is a network of controlled-access highways that forms part of the National Hi ...
. Initial construction work began in the early 1960s, and for many years, only 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.
Route description
I-640 has three lanes in each direction for its entire length, in addition to auxiliary lane
Auxiliary may refer to:
In language
* Auxiliary language (disambiguation)
* Auxiliary verb
In military and law enforcement
* Auxiliary police
* Auxiliaries, civilians or quasi-military personnel who provide support of some kind to a military ...
s between some interchanges. In 2022, annual average daily traffic
Annual average daily traffic (AADT) is a measure used primarily in transportation planning, transportation engineering and retail location selection. Traditionally, it is the total volume of vehicle traffic of a highway or road for a year divided ...
(AADT) counts ranged from 70,244 vehicles per day at the highway's eastern terminus to 104,064 vehicles on the western leg.[ Unlike the other Interstate Highways in Knoxville, however, I-640 rarely experiences severe congestion.]
I-640 begins west of Downtown Knoxville at a semi-directional T interchange
In the field of road transport, an interchange (American English) or a grade-separated junction (British English) is a road junction that uses grade separations to allow for the movement of traffic between two or more roadways or highways, using ...
with I-40 and I-75, where the latter continues onto a concurrency with I-640. Along this section, I-640 is treated as the primary route, with exits numbered according to its mileage. Initially heading northwest, the Interstate immediately passes under State Route 169 (SR 169, Middlebrook Pike) without an interchange.[ A short distance beyond this point, the highway turns north and crosses a ]CSX
CSX Transportation , known colloquially as simply CSX, is a Railroad classes, Class I freight railroad company operating in the Eastern United States and the Canadian provinces of Ontario and Quebec. Operating about 21,000 route miles () of trac ...
railroad mainline, intersecting with SR 62 (Western Avenue) in a partial cloverleaf interchange
A partial cloverleaf interchange or parclo is a modification of a cloverleaf interchange.
The design has been well received, and has since become one of the most popular freeway-to-arterial interchange designs in North America. It has also bee ...
a short distance later. It then veers northeast into the southern fringes of Dutch Valley, running along the northern base of Sharp's Ridge
Sharp's Ridge is a steep ridge in Knoxville, Tennessee, Knoxville, Tennessee, north of the city's downtown. A area of the ridge is maintained as Sharp's Ridge Memorial Park, a city park dedicated to the honor of the area's war veterans. The ri ...
. About later, I-640 reaches an unusual three-level combination interchange, commonly known as the Sharp's Gap Interchange, with US 25W (Clinton Highway), I-75, and the northern terminus of I-275. A series of towering radio masts on Sharp's Ridge dominate the view to the south here.[
]
At this interchange, I-75 splits off, heading north towards Lexington, Kentucky
Lexington is a Consolidated city-county, consolidated city coterminous with and the county seat of Fayette County, Kentucky, United States. As of the 2020 United States census, 2020 census the city's population was 322,570, making it the List of ...
, 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
The Norfolk Southern Railway is a Class I freight railroad operating in the Eastern United States. Headquartered in Atlanta, the company was formed in 1982 with the merger of the Norfolk and Western Railway and Southern Railway. The comp ...
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 road
A frontage road (also known as an access road, outer road, service road, feeder road, or parallel road) is a local road running parallel to a higher-speed, limited-access road. Where parallel high-speed roads are provided as part of a maj ...
s 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 semi-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
Asheville ( ) is a city in Buncombe County, North Carolina, United States. Located at the confluence of the French Broad River, French Broad and Swannanoa River, Swannanoa rivers, it is the county seat of Buncombe County. It is the most populou ...
.
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
The Dwight D. Eisenhower National System of Interstate and Defense Highways, commonly known as the Interstate Highway System, or the Eisenhower Interstate System, is a network of controlled-access highways that forms part of the National Hi ...
, which, at the time, was expected to eventually be authorized by Congress. After the passage of the Federal-Aid Highway Act of 1956
The Federal-Aid Highway Act of 1956, also known as the National Interstate and Defense Highways Act, was enacted on June 29, 1956, when President Dwight D. Eisenhower signed the bill into law. With an original authorization of $25 billion (eq ...
, which initiated the Interstate system, the highway was designated as I-640 by the American Association of State Highway Officials
The American Association of State Highway and Transportation Officials (AASHTO) is a standards setting body which publishes specifications, test protocols, and guidelines that are used in highway design and construction throughout the United St ...
(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 the same time. Work on the segment between I-75/I-275/US 25W and US 441 began in October 1968 and was completed on December 15, 1970.
The remainder of I-640 was initially delayed by disputes over its final alignment and disagreements between the city of Knoxville and the state over the improvement of nearby surface streets. In addition, new requirements imposed by the National Environmental Policy Act
The National Environmental Policy Act (NEPA) is a United States environmental law designed to promote the enhancement of the environment. It created new laws requiring U.S. federal government agencies to evaluate the environmental impacts of ...
(NEPA) of 1969 required that an environmental impact statement
An environmental impact statement (EIS), under United States environmental law, is a document required by the 1969 National Environmental Policy Act (NEPA) for certain actions "significantly affecting the quality of the human environment". An E ...
(EIS) be prepared for the remaining segments. Environmental studies took place between 1973 and 1978, with the Federal Highway Administration
The Federal Highway Administration (FHWA) is a division of the United States Department of Transportation that specializes in highway transportation. The agency's major activities are grouped into two programs, the Federal-aid Highway Program a ...
(FHWA) approving the EIS for the western leg in November 1975 and the EIS for the eastern leg in March 1978. Construction of these sections was then funded as part of a $250 million (equivalent to $ in ) multiphase improvement project on multiple roads in the Knoxville vicinity that was conducted in preparation for the 1982 World's Fair
The 1982 World's Fair, officially known as the Knoxville International Energy Exposition (KIEE) and simply as Energy Expo '82 and Expo '82, was an international exposition held in Knoxville, Tennessee, Knoxville, Tennessee, United States. Focu ...
.[
Construction on the section between I-40/I-75 and I-75/I-275/US 25W began in October 1977, and work to modify the Sharp's Gap Interchange, which included construction of two new flyover ramps, began in August 1978. This section opened to traffic on December 23, 1980.] At this time, I-75 was rerouted onto this section, and the part of I-75 between I-640 and I-40 in downtown Knoxville was renumbered I-275. This was done in an effort to divert through traffic on I-75 away from the World's Fair.[ Work on the final section, located between US 441 and the eastern terminus with I-40, began in July 1979 and was opened to traffic on December 21, 1981.] Final signage, lighting, and landscaping work was completed in April 1982, and the flyover ramp from I-40 eastbound onto I-640 at the eastern terminus opened on July 1, 1983. Then-Governor
A governor is an politician, administrative leader and head of a polity or Region#Political regions, political region, in some cases, such as governor-general, governors-general, as the head of a state's official representative. Depending on the ...
Lamar Alexander
Andrew Lamar Alexander Jr. (born July 3, 1940) is an American politician and attorney who served as a United States senator from Tennessee from 2003 to 2021. A member of the Republican Party, he also was the 45th governor of Tennessee from 1 ...
officially opened both sections by leading a walk along their entire lengths dressed in his red plaid shirt that he famously wore during both of his campaigns for governor.[ I-640 was the last Interstate Highway to be completed from the original 1956 allocation for the ]East Tennessee
East Tennessee is one of the three Grand Divisions of Tennessee defined in state law. Geographically and socioculturally distinct, it comprises approximately the eastern third of the U.S. state of Tennessee. East Tennessee consists of 33 coun ...
Grand Division.[
]
Later history
A new exit ramp from I-640 eastbound to Gap Road was constructed just east of the Sharp's Gap Interchange between December 18, 1985, and August 6, 1986, providing direct access to US 25W from the eastbound lanes for the first time. The section of I-640 between the Sharp's Gap Interchange and US 441 was the only section of the route that was originally four lanes. It was widened to six lanes between January 2000 and June 2003. During this project, the interchange with US 441 was also reconstructed, eliminating a loop exit ramp from I-640 eastbound and reconfiguring parts of the other ramps.[
Between May 1, 2008, and June 12, 2009, through traffic passing on I-40 through Knoxville was required to use I-640 to bypass a complete closure of I-40 through downtown. This was conducted as part of a larger project called "SmartFix 40" to reconstruct and improve this section of I-40. During this time, the ramps at both termini of I-640 carrying this traffic were temporarily widened to three lanes to facilitate the extra volume.
Between April 2016 and July 2019, the interchange with US 441 was further modified. The exit ramp from I-640 westbound was lengthened, and a new loop entrance ramp from US 441 northbound onto I-640 westbound was constructed. On October 21, 2019, the ]speed limit
Speed limits on road traffic, as used in most countries, set the legal maximum speed at which vehicles may travel on a given stretch of road. Speed limits are generally indicated on a traffic sign reflecting the maximum permitted speed, express ...
on I-640 was increased from to , along with the speed limits on sections of other Knoxville-area Interstates, after the Tennessee Department of Transportation
The Tennessee Department of Transportation (TDOT) is the department of transportation for the State of Tennessee, with multimodal responsibilities in roadways, aviation, public transit, waterways, and railroads. It was established in 1915 as the ...
(TDOT) determined that the air quality had greatly improved in the area over the previous 15 years and that the vast majority of drivers were exceeding these limits by large margins.
TDOT reconstructed the mainline surface of I-640 in a two-phase project. The first phase, which took place in 2021, resurfaced the stretch between the Interstate's western terminus and the Sharp's Gap Interchange by removing one layer of asphalt and replacing it with two main layers and a binding layer. The second phase, which began on July 10, 2022, reconstructed the stretch between the Sharp's Gap interchange and the eastern terminus by removing the asphalt surface and rubblizing the original underlying concrete surface to provide a base for a new asphalt surface. The deterioration of the underlying concrete had made this stretch of roadway susceptible to forming cracks and pothole
A pothole is a pot-shaped depression in a road surface, usually asphalt pavement, where traffic has removed broken pieces of the pavement. It is usually the result of water in the underlying soil structure and traffic passing over the affecte ...
s, and had been patched and repaired multiple times. This project was initially slated to be finished by November 30, 2023, but experienced multiple delays resulting from higher-than-expected concrete grades in the surface and potholes on bridges. On August 26, 2024, all lanes were reopened to traffic, and final ramp and shoulder paving work was completed over the next few weeks.
Exit list
See also
*
References
External links
Interstate 640
at Interstate-Guide.com
{{3di, 40
40-6
40-6
640
Year 640 ( DCXL) was a leap year starting on Saturday of the Julian calendar. The denomination 640 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming y ...
Transportation in Knox County, Tennessee
Transportation in Knoxville, Tennessee
640
Year 640 ( DCXL) was a leap year starting on Saturday of the Julian calendar. The denomination 640 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming y ...