Natchez Trace Parkway Road Reconstruction

The Natchez Trace Parkway A Trail Becomes A Parkway. Construc- In some areas, primitive motor roads stretches for 444 miles through tion on the Natchez Trace Parkway began developed along what was originally just a parts of Mississippi, Alabama, trail. In 1934, Congress passed legislation to and Tennessee. (NPS photo.) in 1938. It was completed in 2005 to form a 444-mile route from Natchez, Missis- begin surveying the Natchez Trace Parkway. sippi to Nashville, Tennessee. The Parkway Then in 1938, legislation was passed to be- passes through Mississippi, Alabama and gin construction. Construction was com- Tennessee. Along this route, there are 163 pleted in 2005, sixty-seven years later. overlooks and parking areas, over 1,000 miles of landscaped road shoulders, and The Aging Natchez Trace Parkway. The 485 bridges. Natchez Trace Parkway is celebrating the 75th anniversary this year. Due to their The Natchez Trace Parkway welcomes ap- age, many of the roadways, drainage struc- proximately 14 million visitors each year. In tures, bridges, and pavement structures two urban areas, commuters frequently use along the Trace are in decline. sections of the Parkway, generating from

7,000 – 12,000 average daily traffic (ADT). Roadways. An engineer recognized in 1939 that all soils in Mississippi were troublesome Cultural and Historical Significance. Much from a road-building standpoint. Highly ex- of our country’s history is associated with pansive clays continue to cause problems for the Natchez Trace Parkway. It began as a the Natchez Trace Parkway. Embankment series of trails through the homelands of the stability and failure is an ongoing problem. Native American tribes of Natchez, Choc- * Mega-Project Profile: taw and Chickasaw. In 2012, an eight-mile mile section of the Natchez Trace Parkway Parkway in the heaviest commuter area had Road Reconstruction As time passed, it was used by the Kain- to be closed to repair an embankment failure. tucks. After transporting their goods by way Currently two more repair areas are in the Estimated cost: $250 million of the Ohio, Tennessee, and Mississippi Riv- planning and design stages, and many other ers to market in Natchez or New Orleans, potential repair areas are being monitored. Percentage of SER’s FLTP they travelled back to the Nashville area along the Natchez Trace. Another problem with the expansive soils is Annual Allotment: 590% that ride quality is seriously affected. In some Later, around 1801, the Trace was congres- areas, because of subgrade movement, it is Percentage of NPS FLTP sionally designated as a post road to trans- necessary to always have projects set aside to Annual Allotment: 125% port mail into what was then the Southwest level the riding surface. Territory. Troops were moved along this route during the French and Indian War and Drainage Structures. During construction later during the Civil War. of the Parkway, 3,008 culverts were installed for drainage structures. Two types of culverts were used: metal and concrete. treatment to be $104,127,208, and is broken The metal culverts have been in down as follows: place long enough that the bot- toms are now rusting out. Due • PM: 73% of the mileage – estimated cost to the expansive soils, concrete of $38,355,009 which is 37% of the total pipes have become disjointed cost.($102,000 per mile) and soil is eroding away at the • L3R: 10% of the mileage – estimated cost joints, causing erosion and set- of $16,275,648 which is 16% of the total tlement of the pavement surface. cost. ($309,000 per mile) One method of repair is to • H3R: 16% of the mileage – estimated cost use cured-in-place liners. On of $49,496,551 which is 48% of the total a project that was completed cost. ($594,000 per mile) in 2010, thirty-three culverts were lined at an average cost of • 4R 0.04% of the mileage – estimated cost $40,000 each in 2013 dollars. of $259,000 which is 0.25% of the total This translates to approximately cost. ($1,295,000 per mile) $119,000,000 needed to complete Timely resurfacing of pavements is crucial this work. to cost-effective use of our funds. This data emphasizes that timely preventative main- Bridges. Not only are soils a tenance is extremely cost-effective. In its problem for bridge structures, present condition, 37% of the needed funds but aggregates as well. The silica will cover 73% of the Parkway area. How- in some aggregates is reactive ever, if timely PM is not performed, more with the alkali in cement (ASR), and more areas will shift to the higher cost which causes long-term dete- categories of L3R, H3R and 4R. rioration of concrete. Currently Top: The John Coffee Memo- Natchez Parkway engineers are rial Bridge crossing the Ten- looking at the repair or the replacement of nessee River. three bridges. Others will be added to this Middle: The Birdsong Hollow list. The current deferred maintenance on Bridge, a concrete double- bridges is $28,000,000. arch bridge located 9 miles from the northern terminus of the Natchez Trace Park- Pavements. Allowing road assets to way. deteriorate can cost exponentially more than keeping up with regular preventative Bottom: A portion of the maintenance. Road improvements are cat- original Natchez Trace trail. egorized into these four primary areas: * Mega Projects: The NPS • Preventative maintenance (PM) in- transportation system is supported, in part, by funds cludes basic resurfacing. This is the from the Federal Lands least expensive form of roads mainte- Transportation Program nance; (FLTP). Currently, the NPS is authorized an annual bud- • The “3R” category includes more ex- get of $268 million from the pensive rehabilitation such as structural FLTP. These funds are appor- overlays. The pavements group subcat- tioned by formula among the seven NPS Regions. Most egorizes this into Light 3R (L3R); of these funds are used for “transportation asset • Heavy 3R (H3R). L3R could be removal management” – that is, to of the surface by milling and then plac- pay for the work required ing an asphalt overlay. Heavy 3R (H3R) to keep existing assets in could be multiple lift overlays. good condition. There are some projects, such as a • “4R” is usually total reconstruction of major bridge repair or ship the base and pavement structure that is replacement, that require a much larger amount of the most costly of the treatment catego- funding than is available on ries. an annual basis to a Region. These we call The most recent survey of the pavement “Mega Projects.” The NPS is structures on the Natchez Trace Parkway pursuing strategies to fund shows the total cost of the recommended these projects.

Last Updated 2016 February