Теннесси штатындағы тас жолдар жүйесі

Highway in Tennessee

After this interchange, I 840 crosses a steep hill and continues through terrain consisting of several rolling hills, some with relatively steep grades, and crosses the Harpeth River about 8 mile (13 km) later. 3 mile (5 km) later, I 840 comes to an interchange with U. S. Route 31 Alternate (US 31A) and US 41A near the community of Triune. About 3 mile (5 km) later, I 840 crosses SR 96 at the top of a large hill and begins a steep downgrade; the westbound lanes utilize a truck climbing lane over a short distance to ascend the hill from the east. It then crosses into Rutherford County, entering a more flat terrain and another suburban area, and, about 8 mile (13 km) later, I 840 comes to an interchange with I 24 northwest of Murfreesboro. This interchange is almost a complete cloverleaf, containing three loop ramps and one flyover. The route then turns northeast, traveling through a relatively flat region with little elevation change and interchanges with US 41 and US 70S in a combination interchange about 2 mile (3 km) later. About 0.75 mile (1 km) later, I 840 crosses the west fork of the Stones River, gradually turning northwest. About 4 mile (6 km) later, the highway turns sharply northeast and crosses the east fork of the Stones River about 1 mile (2 km) beyond this point. About 1.5 mile (2 km) later, I 840 shifts north and, another 1.5 mile (2 km) later, crosses the Fall Creek impoundment of J. Percy Priest Lake. A short distance later is an interchange with the western terminus of SR 452 (Bill France Boulevard). I 840 then crosses into Wilson County less than 1 mile (2 km) later and has an interchange with SR 109 about 6 mile (10 km) beyond this point. The route then turns northeast and, about 3.8 mile (6 km) later, reaches its eastern terminus with I 40 west of Lebanon. The I 840 project was initiated in 1986 with the passage of the Better Roads Program by the Tennessee General Assembly. This program, which had been proposed and spearheaded by then governor Lamar Alexander, increased the state's gasoline and diesel taxes to fund six new freeway projects and a backlog of 15 projects that had been labeled as top priorities, as well as other projects. I 840 was the largest of these six freeway projects, dubbed "Bicentennial Parkways", and was initially expected to cost $351 million (equivalent to $ in ). The 1986–1987 state budget contained the initial funding for the project. and the alignment for the remainder of the route was announced in January 1990. The first contract for construction was awarded on August 2, 1991, and work progressed in stages. The segment between Stewart's Ferry Pike and I 24 near Murfreesboro was completed on November 21, 1996. On November 30, 2000, the section between I 24 and US 31A/US 41A near Triune was opened. The portion between US 31A/US 41A and US 431 (Lewisburg Pike) near Franklin, including the interchange with I 65, opened on October 18, 2001. The section between I 40 near Dickson and SR 100 opened on December 5, 2002. Due to high costs and environmental concerns, the proposed northern half of I 840 was indefinitely placed on hold in 2003. Construction of the majority of I 840 was met with very little controversy. Between the late 1990s and mid 2000s, these landowners, spearheaded by singer songwriter Gene Cotton, filed complaints and eventually lawsuits in an effort to have TDOT address both environmental and aesthetic issues, considerably slowing work on the segment between SR 100 and US 31. but additional litigation forced TDOT to completely cease work on this segment three months later. As a result of these lawsuits, TDOT chose to slightly modify the design and employ new construction methods on the remaining sections the following year. As part of the redesign, TDOT formed a citizen's resource team, made up of nine local residents who worked with TDOT to select the final designs and alignment of these stretches. On February 9, 2006, TDOT announced that the realignment of the final segment of I 840 had been chosen and that work on the unfinished sections would proceed. The first contract for construction of the segment between SR 100 and SR 46 was reawarded on June 1, 2007, and construction on I 840 resumed the following month. This segment opened on October 27, 2010. The contract for the segment between Leiper's Creek Road and US 31 was awarded on December 12, 2008, and, on February 19, 2010, TDOT awarded the final construction contract for I 840, the segment between SR 46 and Leiper's Creek Road. These two segments, the final 14.2 mile (23 km) of I 840, were opened on November 2, 2012. Many residents in the predominantly rural and agricultural areas where the route was to pass were initially opposed. The western terminus of I 840 contains a very short unused extension, constructed in anticipation of the northern segment. In 2015, TDOT submitted a request to AASHTO to redesignate SR 840 as I 840. Though the application had an error that required TDOT to refile it, AASHTO conditionally approved it and submitted it to the FHWA for their approval. The FHWA approved the change on July 22, 2015, and AASHTO finalized their approval on September 25, 2015. TDOT announced on August 12, 2016, that it would start replacing the signs to change over the designation the week of August 14 and that the project would be completed by the end of the year at a cost of $230,000 (equivalent to $ in ).

In 2005, the Tennessee General Assembly passed legislation designating I 840 as the "Tennessee National Guard Parkway". Since 2007, the state has named bridges on I 840 in honor of members of the Tennessee National Guard killed in the global War on Terror.