Editing Interstate 24 (section)

===Tennessee===
{{About|the current Interstate Highway|the current state highway|Tennessee State Route 24|section=yes}}
====Clarksville and Western Highland Rim====
I-24 crosses into Tennessee from Kentucky traveling in a southeasterly-to-northwesterly direction into [[Montgomery County, Tennessee|Montgomery County]] and serving as a major means of access to [[St. Louis]] and Chicago to the northwest. Immediately within the eastern outskirts of [[Clarksville, Tennessee|Clarksville]], the fifth-largest city in Tennessee, the Interstate reaches an interchange with [[Tennessee State Route 48|State Route&nbsp;48]] (SR&nbsp;48), less than {{convert|1|mi|km|spell=in}} later, which provides access to [[Trenton, Kentucky|Trenton]] in Kentucky to the north. About {{convert|3|mi|km|spell=in}} later the Interstate reaches [[U.S. Route 79 in Tennessee|US&nbsp;79]], which also provides access to [[Guthrie, Kentucky|Guthrie]] and [[Russellville, Kentucky|Russellville]] in Kentucky to the northeast. Bypassing Clarksville to the east, the Interstate next reaches [[Tennessee State Route 237|SR&nbsp;237]]. The highway then begins a steep descent, with the westbound lanes utilizing a [[truck climbing lane]] to ascend the grade from the east. It then crosses the [[Red River (Cumberland River tributary)|Red River]] before reaching [[Tennessee State Route 76|SR&nbsp;76]].

Leaving Clarksville, the highway enters a long straight section with several steep grades and crosses into [[Robertson County, Tennessee|Robertson County]] a short distance later. Several miles later, the Interstate reaches an interchange with [[Tennessee State Route 49|SR&nbsp;49]] near [[Pleasant View, Tennessee|Pleasant View]] and [[Coopertown, Tennessee|Coopertown]], which provides access to [[Springfield, Tennessee|Springfield]] to the northeast and [[Ashland City, Tennessee|Ashland City]] to the southwest. The route then descends, utilizing another westbound truck lane, before briefly entering [[Cheatham County, Tennessee|Cheatham County]]. The Interstate then crosses another steep hill over the next several miles, utilizing an eastbound truck lane before crossing into [[Davidson County, Tennessee|Davidson County]]. It then has an interchange with [[U.S. Route 431 in Tennessee|US&nbsp;431]] near the [[Joelton, Tennessee|Joelton]] community and begins a gradual descent into the [[Nashville Basin]], containing a westbound truck lane. Passing over the next few miles through dense woodlands, the highway reaches [[Tennessee State Route 45|SR&nbsp;45]] ([[Old Hickory Boulevard]]) about {{convert|5|mi|km|spell=in}} later. Over the next {{convert|3|mi|km|spell=in}} beyond this point, the Interstate crosses over another steep hill, utilizing truck lanes on both the eastbound and westbound ascent before reaching Nashville at [[Tennessee State Route 155|SR&nbsp;155]] (Briley Parkway).

====Nashville metropolitan area====
[[File:I-65 Southbound in Nashville.JPG|thumb|right|I-24 eastbound in Nashville concurrent with I-65]]
Entering Nashville, I-24 has a [[cloverleaf interchange]] with SR&nbsp;155 (Briley Parkway), a northern [[controlled-access]] beltway around Nashville. Less than {{convert|1|mi|km|spell=in}} later, the Interstate joins a concurrency with [[Interstate 65 in Tennessee|I-65]], where the combined routes carry eight throughlanes and travel due south. About {{convert|1|mi|km|spell=in}} later is an interchange with [[U.S. Route 41 Alternate (Tennessee–Kentucky)|US&nbsp;41A]]/[[U.S. Route 431 in Tennessee|US&nbsp;431]] (Trinity Lane). About {{convert|1|mi|km|spell=in}} beyond this point, I-65 splits off and I-24 passes along the east side of downtown Nashville, where it reduces to six lanes and has interchanges with [[U.S. Route 41 in Tennessee|US&nbsp;41]], US&nbsp;431, and [[U.S. Route 31E in Tennessee|US&nbsp;31E]], and passes near [[Nissan Stadium]]. The interstate then crosses the [[Cumberland River]] on the [[Silliman Evans Bridge]] and joins in a concurrency with I-40, traveling southeast-to-northwest with eight throughlanes. {{convert|2|mi|km|spell=In}} later, I-40 splits off eastwardly, heading toward [[Knoxville, Tennessee|Knoxville]]. Located at this interchange is also a partial interchange with US&nbsp;41/[[U.S. Route 70S|US&nbsp;70S]] (Murfreesboro Road).<ref name=davidson>{{cite map |author = Long Range Planning Division Office of Data Visualization |title = Davidson County |year = 2018 |url = https://www.tn.gov/content/dam/tn/tdot/maps/county-maps-(us-shields)/a-g/Davidson%20County.pdf |publisher = Tennessee Department of Transportation }}</ref>

Less than {{Convert|1|mi|km|spell=in}} later is an interchange with the eastern terminus of [[Interstate 440 (Tennessee)|I-440]], which is also accessible from I-40 nearby. Between I-40 and I-440, I-24's eastbound lanes are split into two barrier-separated carriageways to prevent weaving of traffic destined from I-40 to I-440. A short distance later is once again an interchange with SR&nbsp;155 (Briley Parkway/Thompson Lane) near [[Nashville International Airport]]. Beginning at the next exit, [[Tennessee State Route 255|SR&nbsp;255]] (Harding Place), the left lanes operate as [[high-occupancy vehicle]] (HOV) lanes during rush hour. Over the next few miles, I-24 passes through the [[Antioch, Tennessee|Antioch]] neighborhood, where it has interchanges with Haywood Lane and [[Tennessee State Route 254|SR&nbsp;254]] (Bell Road), and crosses [[Mill Creek (Davidson County, Tennessee)|Mill Creek]]. I-24 then continues through southeast Nashville, reaching interchanges with Hickory Hollow Parkway and [[Tennessee State Route 171|SR&nbsp;171]] (Old Hickory Boulevard).<ref name=davidson/>

[[File:I-24 West Exit 66 - TN266 (32888023233).jpg|thumb|left|I-24 westbound in Smyrna, a suburb of Nashville]]
Continuing through the southeastern suburbs of Nashville, I-24 crosses into [[Rutherford County, Tennessee|Rutherford County]] about {{convert|2|mi|km|spell=in}} beyond. Immediately within the city of [[La Vergne, Tennessee|La Vergne]], the Interstate has an exit with a connector road to that city. It then enters [[Smyrna, Tennessee|Smyrna]] where it first has an interchange with [[Tennessee State Route 266|SR&nbsp;266]] (Sam Ridley Pkwy.). The Interstate then enters a long straightaway and reaches an interchange with [[Tennessee State Route 102|SR&nbsp;102]] (Almaville Road), which also serves Smyrna and the [[Nissan Smyrna Assembly Plant]]. Leaving Smyrna, the route enters an unincorporated urban area, before reaching a three-level interchange with [[Interstate 840 (Tennessee)|I-840]], the outer southern beltway around Nashville. I-24 then enters Murfreesboro, the largest suburb of Nashville and sixth-largest city in Tennessee. The Interstate first has an interchange with a local thoroughfare (Medical Center Parkway/Fortress Blvd), before reaching [[Tennessee State Route 96|SR&nbsp;96]], which also connects to [[Franklin, Tennessee|Franklin]]. A short distance later, the Interstate crosses the west fork of the [[Stones River]] and reaches [[Tennessee State Route 399|SR&nbsp;99]] (New Salem Highway). A short distance later, the highway reaches [[U.S. Route 231 in Tennessee|US&nbsp;231]], which also connects to [[Lebanon, Tennessee|Lebanon]] and [[Shelbyville, Tennessee|Shelbyville]]. Here, the HOV lane restriction terminates, and the Interstate reduces from eight to four lanes. Leaving Murfreesboro, the Interstate {{convert|3|mi|km|spell=in}} later has an interchange with the [[Joe B. Jackson Parkway]], which serves as an outer beltway around southeast Murfreesboro.

====Eastern Nashville Basin and Eastern Highland Rim====
[[File:I-24 West - Exit 110 - TN53 (46295736504).jpg|thumb|right|I-24 westbound in Manchester]]
Upon leaving Murfreesboro, I-24 enters a rural area, passing through a mix of farmland and woodlands and maintaining a straight alignment. Several miles later, the Interstate begins a gradual, largely unnoticeable, ascent out of the Nashville Basin onto the eastern [[Highland Rim]]. A few miles later, the Interstate briefly enters [[Bedford County, Tennessee|Bedford County]] and then has an interchange with [[Tennessee State Route 64|SR&nbsp;64]], which connects to Shelbyville, near the Bedford–[[Coffee County, Tennessee|Coffee]] county line. I-24 then briefly descends, curves to the south, then the east, before once again resuming its gradual ascent, where it surpasses an elevation of {{convert|1000|ft|m}} for the first time in Tennessee.<ref name=topo>{{cite map |map-url = https://en-gb.topographic-map.com/maps/lsuz/Tennessee/ |map = Tennessee |author = Topographic-Map.com |date = January 22, 2022 |title = Topographic-Map.com |publisher = <!--Needed--> |access-date = January 22, 2022 }}</ref> Upon reaching the top of the rim several miles later, the interstate has an interchange with US&nbsp;41. {{convert|5|mi|km|spell=In}} later, the highway enters [[Manchester, Tennessee|Manchester]], where it crosses the [[Little Duck River]] and then has interchanges with [[Tennessee State Route 53|SR&nbsp;53]] and [[Tennessee State Route 55|SR&nbsp;55]] in short proximity. A short distance later, the highway reaches an interchange with US&nbsp;41 once again. Leaving Manchester, the Interstate maintains its relatively straight trajectory and passes through the northeastern corner of [[Arnold Air Force Base]] over a distance of about {{convert|3|mi|km|spell=in}}. The Interstate then travels over the next {{convert|10|mi|km}} through a wide swath of mostly farmland, before entering [[Grundy County, Tennessee|Grundy County]] and reaching an interchange with [[U.S. Route 64 in Tennessee|US&nbsp;64]] and [[Tennessee State Route 50|SR&nbsp;50]] near the town of [[Pelham, Tennessee|Pelham]], where it begins a concurrency with the former route that is largely unsigned. A short distance later, I-24 crosses the [[Elk River (Tennessee River tributary)|Elk River]], before reaching the base of the [[Cumberland Plateau]].

====Monteagle Mountain and Cumberland Plateau gorge====
{{see also|Monteagle Mountain}}
One of the most hazardous stretches of Interstate Highway in the US is located where I-24 crosses the Cumberland Plateau on steep grades in Grundy and [[Marion County, Tennessee|Marion County]] near the town of [[Monteagle, Tennessee|Monteagle]] and is commonly known as "[[Monteagle Mountain]]" or "Monteagle". While all motorists are advised to exercise caution along this stretch, truckers are particularly vexed by Monteagle, and many have died in accidents along this stretch. The eastbound grade is particularly hazardous, with a protracted four-to-six-percent grade over several miles. On this stretch, I-24 is three lanes in each direction and contains two [[runaway truck ramp]]s. Owing to geography, these two ramps are on the left side of the grade. The westbound downgrade of the plateau is also extremely hazardous and contains several sharp curves. Portions of this downgrade also feature offramp approach style lane dividers in order to slow motorists. Throughout the entire stretch across the Cumberland Plateau, the speed limit reduces to a maximum of {{convert|55|mph|km/h|abbr=on}} and {{convert|45|mph|km/h|abbr=on}} for trucks on both downgrades. At top of the Plateau, the Interstate surpasses {{convert|2000|ft|m}} in elevation, has interchanges with [[U.S. Route 41 Alternate (Tennessee–Kentucky)|US&nbsp;41A]] and US&nbsp;41, respectively, and crosses into [[East Tennessee]] at the Grundy–Marion county line.

The eastern Monteagle grade also has one of the three widest medians of any Interstate Highway; the others are [[Interstate 8|I-8]] through the In-Ko-Pah grade in California and [[Interstate 84 (Oregon–Utah)|I-84]] through the Cabbage Hill grade east of [[Pendleton, Oregon]]. There is more than {{convert|1|mi|km|spell=in}} between the eastbound and westbound lanes at one point. The eastbound lanes descend the hill on one side of Monteagle Mountain as part of the original three-lane (two ascending and one descending) US&nbsp;64 alignment, while the westbound lanes ascend the other side of the hill on new roadbed built for that purpose.

[[File:I-24 West - Exit 152AB - US72 US64 To US41 (32818385041).jpg|thumb|left|Westbound I-24 at the US&nbsp;72 interchange]]
After descending Monteagle, I-24 travels for several miles through a vast flat gorge within the plateau characterized by long straightaways and few curves before reaching an interchange with [[U.S. Route 72|US&nbsp;72]] near [[Kimball, Tennessee|Kimball]] and [[South Pittsburg, Tennessee|South Pittsburg]], where US&nbsp;64 splits off. This exit is the primary means of access to [[Huntsville, Alabama]], for motorists in East Tennessee. About {{convert|3|mi|km|spell=in}} later, the Interstate has an interchange with [[Tennessee State Route 28|SR&nbsp;28]] in [[Jasper, Tennessee|Jasper]] and crosses the [[Sequatchie River]]. Beyond this point, the east and westbound lanes split more than {{convert|1/2|mi|m|spell=in}} apart over a few miles, encompassing farms, homes, and a few businesses in between. The route then crosses a large mountain ridge, has an interchange with [[Tennessee State Route 27|SR&nbsp;27]], and, about {{convert|1|mi|km|spell=in}} later, crosses the [[Nickajack Lake]] impoundment of the [[Tennessee River]]. Beyond this point, the highway travels through a narrow gorge over several miles, crossing the Running Water Creek and traveling under its namesake [[Trestle bridge|trestle]]. This stretch is extremely crooked and can experience potentially strong [[crosswind]]. The Interstate then enters [[Hamilton County, Tennessee|Hamilton County]] and the [[Eastern Time Zone]] and then crosses into Georgia less than {{convert|1/4|mi|m|spell=in}} later.