Interstate 40 in Tennessee

West Tennessee

I-40 enters Tennessee from Arkansas via the Hernando de Soto Bridge, which spans the Mississippi River at river mile 736. The Interstate passes across the southern half of Mud Island before crossing the Wolf River Harbor into downtown Memphis. At the I-240 interchange, I-40 abruptly turns north, following the route redesignated due to the Overton Park controversy in the 1970s. I-40 crosses the Wolf River three times in Memphis, as the road passes near the neighborhoods of Frayser and Raleigh and turns back onto the original routing of I-40 (the western continuation of what would have been I-40 at this point is known as Sam Cooper Boulevard).

I-40 leaves the Memphis area, crosses over the Loosahatchie River and Hatchie River, the latter near Brownsville. At mile 78, the road crosses the South Fork of the Forked Deer River into Jackson, and from Jackson proceeds through the northern half of Natchez Trace State Park. At mile 135, I-40 crosses the Tennessee River into Middle Tennessee.

The first 130 miles (210 km) of the Interstate in Tennessee are relatively flat as the road traverses the Gulf Coastal Plain, but there are some gentle to moderately rolling hills, especially as one continues eastward into the higher areas of West Tennessee. Some of the steepest or most rugged sections in West Tennessee are between miles 21–27, around mile 56 (near the Hatchie River crossing), between miles 79–85 around Jackson, around Natchez Trace State Park, and just to the west of the Tennessee River as the road descends about 400 feet (120 m) over the course of a mile.

Middle Tennessee

East of the Tennessee River, the rugged hills of the Western Highland Rim flank I-40 for a considerable stretch before the Interstate descends to the Nashville Basin between miles 186 and 188. In Downtown Nashville, I-40 converges with I-24 and I-65, making Nashville one of just four cities in the United States where six interstate legs converge within the city's boundaries. At mile 219, the Interstate crosses the Stones River just downstream from Percy Priest Dam, and continues for roughly 50 miles (80 km) across mostly open farmland.

Between miles 263 and 266, I-40 crosses the meandering Caney Fork five times before ascending the Eastern Highland Rim, reaching 1,000 feet (300 m) for the first time in the state near Silver Point. The Interstate steadies at the edge of the table-top rim at mile 272 (near Baxter) and continues across relatively flat farmland in south Cookeville. Between miles 292 and 297, the Interstate ascends the western escarpment of the Cumberland Plateau, reaching 2,000 feet (610 m) southeast of Monterey. At mile 308, I-40 crosses the Tennessee Divide, where the Cumberland and Tennessee River watersheds meet (in the eastbound lane, the divide is marked by a sign reading "Entering Emory River watershed"; its westbound lane counterpart notes the beginning of the Caney Fork watershed).

East Tennessee

I-40 remains relatively steady as it continues across the Cumberland Plateau and passes through the northern part of Crossville. East of Crossville, the Crab Orchard Mountains (the southern fringe of the Cumberland Mountains) come into view as the road descends several hundred feet. At mile 329, the Interstate enters Crab Orchard Gap and proceeds through a narrow valley once prone to rockslides. At mile 340, the Interstate enters the Eastern Time Zone, and shortly thereafter the road begins its descent of the Cumberland Plateau into the Tennessee Valley. I-40 hugs the slopes of the plateau's Walden Ridge escarpment for several miles— with dramatic views of the Tennessee Valley below to the south— before reaching the base of the plateau at mile 347 between Harriman and Rockwood.

As it enters the Ridge-and-Valley province (of which the Tennessee Valley is a part), I-40 crosses a series of ridges and valleys characteristic of the region's topography. At mile 351, the road crosses the Clinch River, with the Kingston Fossil Plant and its 1,000-foot (300 m) twin smokestacks dominating the view to the north. The road widens to four lanes at mile 368 as I-40 merges with I-75. Knoxville's skyline comes into view at mile 387 before the road passes through downtown Knoxville.

Beyond Knoxville, the Interstate crosses the Holston and French Broad rivers (the French Broad is much wider due to its impoundment by Douglas Dam a few miles downstream) and continues for several miles along the northern base of English Mountain. At mile 440, the road turns south through the gap between English Mountain and Stone Mountain, revealing a dramatic view of the 4,928-foot (1,502 m) Mount Cammerer at the northeastern end of the Great Smokies range, and the road proceeds into the Pigeon River Gorge, closely following the north bank of the river. The massive mesh nets on the cliffslopes are indicative of the rockslide prevention measures along this stretch of I-40.

Music Highway

The term Music Highway refers to a section of I-40 between Memphis and Nashville. I-40 was designated as such by an act of the Tennessee Legislature in 1997 "from the eastern boundary of Davidson County to the Mississippi River in Shelby County," a distance of about 222 miles (357 km). I-40 is designated as such because of the rich music history in Memphis, Nashville, and the areas in between them. Memphis is known as "the Home of the Blues and the Birthplace of Rock and Roll." Nashville is known as "Music City USA" for its influence on numerous types of music, especially country. Several cities and towns between the two, such as Jackson, Brownsville, Nutbush (Near Ripley), Waverly and others were birthplaces or homes of numerous singers and songwriters. Signs that display the words "Music Highway" along with music notes are erected in both directions along I-40, especially at the borders of Shelby County and Davidson County (Nashville).

History

The Tennessee leg of I-40 was part of the original 1,047 miles (1,685 km) of Interstate Highways authorized for Tennessee by the Federal Aid Highway Act of 1956. The first section of Interstate 40—Nonconnah Creek to Hindman Ferry Road in Shelby County (originally I-240)—was contracted in 1956, and within a year contracts had been awarded for sections in Davidson, Knox, Roane, Haywood, Madison, Jefferson, and Cocke counties. By 1958, sections in Loudon, Smith, Putnam, Cumberland, Humphreys, Hickman, and Sevier counties had been contracted. Most of I-40 had been completed by the late 1960s.

In Memphis, I-40 was originally slated to pass through the city's Overton Park, a 342-acre (138 ha) wooded refuge that had become an important stopover for migratory birds. Fearing that the Interstate's construction would upset the park's fragile ecological balance, environmentalists waged a 12-year legal battle to prevent highway construction in the park, culminating in the United States Supreme Court decision, Citizens to Preserve Overton Park v. Volpe. The Supreme Court remanded the case to the District Court for further review, and it ruled that the highway commission had not adequately explored alternative routes. In 1981, the highway commission abandoned plans to route I-40 through Overton Park, and instead redesignated the northern portion of I-240 as I-40. For over 20 years, I-40 signage existed on the dead-end route toward Overton Park. To this day, signs still exist on overhead gantries leading westbound drivers on Sam Cooper "To Little Rock". Several miles of a limited-access road were actually built within the I-240 loop; this portion of highway still exists and is in regular use as Sam Cooper Boulevard, reaching the eastern end of Chickasaw Country Club and the Binghampton neighborhood, and then East Parkway.

SmartFix 40

Until June 12, 2009, a section of I-40 through downtown Knoxville between James White Parkway and Hall of Fame Drive was completely closed to all traffic for about 18 months for reconstruction. Through traffic was required to use I-640 or to use surface streets. The four-lane section, which was quite substandard, congested, and accident-prone, was widened to six lanes to improve traffic flow and safety. Several interchanges along that stretch were also reconstructed.

Geological difficulties

The rugged terrain of East Tennessee presented numerous challenges for I-40 construction crews and engineers. Rockslides, especially along the eastern Cumberland Plateau and in the Pigeon River Gorge, have been a persistent problem since the road's construction.

Crab Orchard

In December 1986, a truck driver was killed when his truck skidded across some rocks that had spilled across the road just east of Crab Orchard (between miles 331 and 333). In response, the Tennessee Department of Transportation (TDOT) flattened the cutslopes along this stretch of Interstate and moved the road 60 feet (18 m) away from the problematic cliffside.

Twenty rockslides occurred along the Walden Ridge section (miles 341–346) of the eastern plateau in 1968 alone, prompting various remedial measures throughout the 1970s, including the employment of rock buttresses, gabion walls, and horizontal drains. A minor rockslide shut down the right lane of westbound I-40 at mile 343 on May 6, 2013.

Pigeon River Gorge

An area very prone to rockslides is the Pigeon River Gorge, especially in the vicinity of the Tennessee–North Carolina state line. Throughout the 1970s, this stretch of I-40 was repeatedly shut down by rockslides, sometimes for several weeks at a time. In the late 1970s and early 1980s, TDOT dug over 24,000 feet (7,300 m) of horizontal drains, blasted out large volumes of unstable rocks, and installed massive mesh catchment fences. Nevertheless, rockslides in 1985 and 1997 again forced the closure of I-40 in the Pigeon River Gorge for several weeks. Additional stabilization measures were implemented, including the blasting of loose rock, the installation of rock bolts, and the construction of a better drainage system. In spite of these measures, another massive rock slide occurred in the Pigeon River Gorge on October 26, 2009, blocking all lanes just across the border at North Carolina mile 3. The section was closed to traffic in both directions until April 25, 2010. On January 31, 2012, the westbound lanes of I-40 were closed because of a rockslide near the North Carolina border. Traffic was detoured along I-26 and I-81 and reopened a few months later.

Sinkholes

Sinkholes are a consistent issue along highways in East Tennessee. One particularly problematic stretch is a section of I-40 between miles 365 and 367 in Loudon County, which is underlain by cavernous rock strata. In the 1970s and 1980s, TDOT employed numerous stabilization measures in this area, including backfilling existing sinkholes with limestone, collapsing potential sinkholes, and paving roadside ditches to prevent surface water from seeping into the volatile soil.

Future

TDOT officially announced the I-40/I-81 Corridor Feasibility Study on July 27, 2007. The intent of this study is to assess deficiencies along I-40 and I-81 in Tennessee and to develop upgrade proposals for the existing corridor. This study was completed in 2008.

On January 18, 2008, the Federal Highway Administration authorized the states of Mississippi and Tennessee to extend I-69 from the I-40/SR 300 interchange in north Memphis to the I-55/I-69 interchange in Hernando, Mississippi; however, Tennessee has not yet signed the extension of the route, although Mississippi has already done so.

Construction is currently taking place to reconfigure the I-40/I-240 interchange in East Memphis. This reconfiguration is needed since the original configuration was designed as if I-40 were to go through the center of the city along what is now Sam Cooper Boulevard. The first phase of the project replaced a one-lane loop ramp from I-40 westbound to I-240 southbound with a two-lane flyover. Portions of both Interstates were also widened slightly. This phase was completed in 2003. The second phase (currently underway) was stalled due to funding and redesign. It includes the installation of the remaining flyover from the north loop of I-40 to I-40 eastbound. This will replace a one-lane ramp with a slow design speed that has been the site of several accidents over the years. Other parts of this phase include widening of I-40 between Sycamore View Road and Covington Pike (requiring the replacement of the Wolf River Bridge with a 14-lane bridge), widening of I-240, addition of through lanes on Sam Cooper Boulevard, and reconfiguration of the Covington Pike interchange. The project will cost $109 million (the highest bid project in TDOT history), began late 2013, and should be completed in 2017. The I-40 flyover and expansion of Sam Cooper Boulevard should be completed in 2015.

A fifth interchange is being added along the stretch of interstate around Cookeville, TN, and a road will be built leading to nearby U.S. Route 70N to help ease traffic along Tennessee State Route 56 (I-40 Exit 280), Tennessee State Route 135 (I-40 Exit 286), and Tennessee State Route 136 (I-40 Exit 287). The initial route will be 2 lanes with a modified diamond interchange, with the right-of-way for future expansion.

Auxiliary routes