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Third Infantry Division Highway Corridor Study

5.0 Cost Estimates

Based on the results of the fatal flaw screening and the recommendations of the EWG, the alternative scenarios presented in Table 5 were advanced. It was determined that the other corridors were unreasonable and therefore should be eliminated from further consideration. The next step in the analysis process involved preparing cost estimates and an outline for the steps anticipated to construct the corridor.

Table 5 – Alternative Scenarios Advanced for Cost Estimates
Corridor Design Level
A West (entire length*) Interstate Design Level
A West (entire length*) Arterial Design Level, plus reusing existing Interstate segments
A West (entire length*) Super-2 Design Level, plus reusing existing Interstate and Arterial segments
A West (entire length*) Minimal Build Option – involves reusing existing roadway alignments available today, with minor spot improvements and two lane highways for new alignment sections
B/B Bypass
(Savannah to Millen)
Interstate or Arterial Design Level
No Build

Installing signage along existing Interstate route
(as suggested by the EWG)

* A West costs were developed for the entire corridor length (Savannah to Knoxville) and for the GA portion (Savannah to Chatsworth) with a spur at Dalton to I-75.

To develop cost estimates, the consultant team employed planning-level cost estimating tools developed by GDOT and TDOT for sections of the corridor within respective States. The following subsections present an overview of the State costing methodologies and specific costs for the corridors.

5.1 GDOT Cost Estimating Methodology

The general procedure and tools developed by GDOT were used to estimate the planning-level cost of approximately 350 miles of the corridor within Georgia. Based on the GDOT estimating procedure, the total cost is the sum of four components: Right-of-Way, Utilities, Construction, and Preliminary Engineering.

For Right-of-Way elements, GDOT assigns unit costs per acre. Unit costs vary by county, project type (widening existing facilities or construction on new alignments), and by area type (commercial, residential, agricultural, or industrial). Costs are inflated to account for administration and contingencies. Unadjusted right-of-way unit costs range from $5,000 to $25,000 per acre for agricultural uses and from $100,000 to $1 million per acre for commercial uses.

For Utility elements, GDOT assigns unit costs per mile. Utility unit costs account for relocation of water lines, gas lines, and power poles for all non-Interstate projects, plus sewer lines for urban non-Interstate projects. Contingencies are factored into the utility cost estimate. Per-mile utility costs are estimated at $1.2 million for rural non-Interstate routes and $1.8 million for urban non-Interstate routes. No utility costs are associated with Interstate projects, unless an existing highway is being upgraded to Interstate standards.

Construction unit costs account for the project type (widening existing roadway/bridge or constructing new roadway/bridge on new alignments), area type (rural or urban), and facility type (Interstate, 2-lane highway, 3-lane highway, or 4-lane highway). The proposed roadway width and project length are multiplied by the unit cost; a contingency factor is applied based on the project type to account for unknown elements which have not been defined at the planning-level. Table 6 presents unadjusted construction unit costs for different project types in urban and rural areas.

Table 6 – GDOT Unadjusted Construction Costs* by Project Type
Project Type Rural Urban
Widen existing Interstate $85,000 $120,000
Widen existing non-Interstate $83,000 $126,000
Construct new 2-lane highway $130,000 $161,000
Construct new 4-lane highway/Interstate $186,000 $245,000
Widen existing bridge $770,000
Construct new bridge $640,000

* Costs presented per foot of new width x mile of project length

Preliminary Engineering includes design, environmental, and public involvement work that must be completed before construction begins. This element is estimated as 10 percent of the total project cost.

The sum of these four elements represents the total project cost. Costs are presented in 2010 dollars.

5.2 TDOT Cost Estimating Methodology

The TDOT cost estimating procedure was developed based on actual project costs collected over the past decades. Based on the TDOT estimating procedure, the total cost is the sum of three components: Right-of-Way, Construction, and Preliminary Engineering. Utility costs are included in the Construction element in the TDOT model.

The Right-of-Way unit cost is adjusted to account for the area type (rural, residential, industrial, commercial, central business district, etc.). Before this adjustment factor is applied, right-of-way is estimated to cost $93,000 per mile.

Construction unit costs are adjusted to account for terrain (flat, rolling, mountainous, or heavy mountainous) and project type (reconstruction/new construction and number of lanes). Per-mile construction costs range from $7.9 million to widen a two-lane highway to four lanes on rolling terrain to $28.3 million to construct a new four-lane Interstate through mountainous terrain.

Other construction costs are estimated per item. For example, grade-separated interchanges are assigned a cost between $10 million and $30 million each, depending on complexity and engineering judgment. Signalized intersections are assigned a cost between $75,000 and $100,000 each. Costs may also be added to account for sidewalks, welcome centers/rest areas, roundabouts, and major structures.

Preliminary Engineering includes design, environmental, and public involvement work that must be completed before construction begins. This element is estimated as 10 percent of the construction costs.

Typically, TDOT does not apply contingency costs this early in the project development process. However, for this study, a 10 percent contingency was applied to the total project cost. This will account for project elements identified in the scope which are not specifically covered in the TDOT model: environmental mitigation, erosion control, wetland management, landscaping, intelligent transportation systems, and other unknown costs. In addition, 10 percent was added to the construction cost to account for construction engineering and inspection services.

The sum of the Right-of-Way, Construction, and Preliminary Engineering elements, plus a 10 percent contingency, represent the total project costs. Costs for the TN portions were developed in 2009 dollars and have been projected to 2010 dollars using a 3.6 percent annual inflation rate.

5.3 Cost Estimates for Study Corridors

Using the methodologies developed by TDOT and GDOT, planning-level cost estimates were prepared for the entire length of Corridor A West for each of the four design levels, for Corridors B and B Bypass between Savannah and Millen at the Interstate and Arterial design levels, and for the No Build option. These are presented in the following subsections; all dollar values are rounded to the nearest million dollars.

Costs were developed to bring all portions of each segment up to the relevant design level. For example, if a four-lane arterial runs from Location X to Y, and a three-lane highway continues from Location Y to Z, the following method would be used:

a. Corridor A West Costs

Corridor A West was divided into 16 sections for costing purposes. Sections were divided at control points, urban areas, and where the corridor transitions between existing highways. Costs for these 16 sections are described below. Figure 9 illustrates the location of each section within the corridor and associated costs for each design level.

Summing the costs for each of the sections, the total cost to construct the 435-mile Corridor A West is estimated at $700 million to $4.8 billion, as shown in Table 7.

Table 7 – Corridor A West Total Costs, by Phase and Design Level
Min. Build Super-2 Arterial Interstate
Engineering $65 million $113 million $237 million $468 million
ROW $68 million $108 million $313 million $576 million
Utility* $73 million $176 million $198 million $252 million
Construction $483 million $790 million $1.716 billion $3.680 billion
TOTAL** $701 million $1.216 billion $2.501 billion $4.845 billion
GA Total $564 million $902 million $2.099 billion $4.316 billion
TN Total $137 million $314 million $402 million $529 million

* Utility costs presented for GA portion only; TN utility costs included in construction category
** Additional 10% contingency added to total project costs within TN

I-16, Savannah to US 25 – 48 miles of existing four-lane Interstate
Planned Projects: No projects are included within Georgia's Statewide Transportation Improvement Program (STIP).
Assumptions: No improvements included for this section.

Figure 9a: Click for long description

Figure 9b: Click for long description

Figure 9c: Click for long description

Figure 9d: Click for long description

Cost Estimate: No improvements included since the existing alignment satisfies the criteria for each of the design levels.

US 25, I-16 to Millen – 38 miles of existing four- to five-lane arterial
Planned Projects: No projects are included within Georgia's STIP.
Assumptions: Right-of-way is primarily rural, predominantly used for agricultural purposes with some commercial and industrial uses.
Cost Estimate:

Table 8A
  Min. Build Super-2 Arterial Interstate
Engineering n/a n/a existing $25 million
ROW n/a n/a existing $22 million
Utility n/a n/a existing $44 million
Construction n/a n/a existing $156 million
Project Total n/a n/a existing $247 million

US 25, Millen to Waynesboro – 30 miles of existing four- to five-lane arterial
Planned Projects: No projects are included within Georgia's STIP.
Assumptions: Right-of-way is a mix of rural and urban areas, but predominantly used for agricultural purposes with some commercial and residential development.
Cost Estimate:

Table 8B
  Min. Build Super-2 Arterial Interstate
Engineering n/a n/a existing $25 million
ROW n/a n/a existing $41 million
Utility n/a n/a existing $36 million
Construction n/a n/a existing $152 million
Project Total n/a n/a existing $254 million

New Alignment, Waynesboro to I-20 – 35 miles on new alignment
Planned Projects: No projects are included within Georgia's STIP.
Assumptions: Right-of-way is rural agricultural.
Cost Estimate:

Table 8C
  Min. Build Super-2 Arterial Interstate
Engineering $26 million $31 million $52 million $73 million
ROW $13 million $16 million $32 million $42 million
Utility $36 million $41 million $39 million n/a
Construction $189 million $223 million $400 million $612 million
Project Total $264 million $311 million $523 million $727 million

US 78, I-20 to Washington – 22 miles of four- to five-lane arterial planned
Planned Projects: A project to widen US 78 from SR 43 to the Washington Bypass to four- to five lanes is scheduled in Georgia's 2010 STIP (projects 222250, 222255) with right-of-way funding in 2011 and construction funding after 2014.

Assumptions: Interstate costs presented are calculated based on improving the upgraded four- to five lane arterial identified in the STIP. Right-of-way is primarily rural, predominantly used for agricultural purposes with some commercial and residential development.
Cost Estimate:

Table 8D
  Min. Build Super-2 Arterial Interstate
Engineering n/a n/a planned $14 million
ROW n/a n/a planned $19 million
Utility n/a n/a planned $27 million
Construction n/a n/a planned $81 million
Project Total n/a n/a planned $141 million

US 78, Washington to Athens – 43 miles of existing two- to four-lane highway
Planned Projects: Segments are identified for widening in the 2010 Georgia STIP. Passing lanes are included in the 2010 STIP for a 5-mile section of
US 78 with right-of-way funding in 2011 and construction funding after 2014.
Assumptions: Right-of-way is primarily urban and contains a mixture of residential, commercial, and agricultural uses.
Cost Estimate:

Table 8E
  Min. Build Super-2 Arterial Interstate
Engineering existing $8 million $17 million $37 million
ROW existing $5 million $45 million $80 million
Utility existing $33 million $46 million $51 million
Construction existing $16 million $59 million $207 million
Project Total existing $62 million $167 million $375 million

US 441, Athens to I-85 – 26 miles of existing three- to four-lane arterial
Planned Projects: A project to widen the three-lane segment of US 441 to the Clarke County line is included in the statewide long-range transportation plan. However, it is not considered a committed project since funding is not allocated in the current Georgia STIP.
Assumptions: Right-of-way is a mixture of rural and urban areas, divided between commercial and residential uses.

Cost Estimate:

Table 8F
  Min. Build Super-2 Arterial Interstate
Engineering n/a n/a $2 million $26 million
ROW n/a n/a $7 million $38 million
Utility n/a n/a $4 million $33 million
Construction n/a n/a $3 million $163 million
Project Total n/a n/a $16 million $260 million

US 441, I-85 to Homer – 7 miles of existing four-lane arterial
Planned Projects: No projects are included in Georgia's STIP.
Assumptions: Right-of-way is primarily urban, predominantly used for residential development with some commercial uses.
Cost Estimate:

Table 8G
  Min. Build Super-2 Arterial Interstate
Engineering n/a n/a existing $14 million
ROW n/a n/a existing $7 million
Utility n/a n/a existing $9 million
Construction n/a n/a existing $109 million
Project Total n/a n/a existing $139 million

New Alignment, Homer to Dahlonega – 31 miles on new alignment
Planned Projects: No projects are included in Georgia's STIP.
Assumptions: Right-of-way is primarily rural residential.
Cost Estimate:

Table 8H
  Min. Build Super-2 Arterial Interstate
Engineering $30 million $34 million $58 million $82 million
ROW $35 million $42 million $77 million $98 million
Utility $37 million $37 million $37 million n/a
Construction $198 million $229 million $411 million $638 million
Project Total $300 million $342 million $583 million $818 million

SR 52, Dahlonega to Ellijay – 33 miles of existing two-lane highway
Planned Projects: No projects are included in Georgia's STIP.
Assumptions: The Super-2 design level includes costs to upgrade the existing SR 52 alignment; the Arterial and Interstate levels assume a new facility on new alignment outside the National Forest boundary. Right-of-way is primarily rural residential and passes through mountainous terrain.

Cost Estimate:

Table 8I
  Min. Build Super-2 Arterial Interstate
Engineering existing $12 million $66 million $86 million
ROW existing $9 million $82 million $104 million
Utility existing $38 million $39 million n/a
Construction existing $62 million $476 million $671 million
Project Total existing $122 million $663 million $861 million

US 76, Ellijay to Chatsworth – 20 miles of existing two- to three-lane highway
Planned Projects: Minor realignments of US 76 are proposed at either end of this segment; however, these are not considered committed projects since funding is not allocated in the current STIP.
Assumptions: Right-of-way is primarily rural, predominantly used for residential developments with some commercial and agricultural uses.
Cost Estimate:

Table 8J
  Min. Build Super-2 Arterial Interstate
Engineering existing $4 million $8 million $21 million
ROW existing $3 million $22 million $38 million
Utility existing $15 million $22 million $24 million
Construction existing $15 million $32 million $124 million
Project Total existing $37 million $84 million $207 million

US 411, Chatsworth to TN/GA state line – 21 miles of existing two- to four-lane highway
Planned Projects: Widening near the northern end of the segment is included in the statewide long-range transportation plan; however, it is not considered a committed project since funding is not allocated in the current Georgia STIP.
Assumptions: Right-of-way contains both urban and rural areas, with a mixture of residential, commercial, and industrial land uses.
Cost Estimate:

Table 8K
  Min. Build Super-2 Arterial Interstate
Engineering existing $3 million $6 million $29 million
ROW existing $2 million $13 million $48 million
Utility existing $11 million $11 million $28 million
Construction existing $12 million $33 million $182 million
Project Total existing $28 million $63 million $287 million

US 411, TN/GA state line to US 64 – 8 miles of existing two-lane highway
Planned Projects: No projects are included in Tennessee's STIP.
Assumptions: Right-of-way lies in rolling terrain, containing a mix of residential and commercial land uses.
Cost Estimate:

Table 8L
  Min. Build Super-2 Arterial Interstate
Engineering existing $6 million $9 million $11 million
ROW existing $8 million $11 million $14 million
Utility/Const. existing $71 million $97 million $129 million
Project Total1 existing $94 million $129 million $170 million

New Alignment, US 64 to US 11 – 12 miles on new alignment
Planned Projects: No projects are included in Tennessee's STIP.
Assumptions: Right-of-way lies in rolling terrain, containing a mix of residential and commercial land uses.
Cost Estimate:

Table 8M
  CSD Super-2 Arterial Interstate
Engineering $9 million $11 million $14 million $18 million
ROW $20 million $20 million $20 million $20 million
Utility/Const. $96 million $123 million $153 million $199 million
Project Total5 $137 million $170 million $206 million $261 million

SR 308, at Charleston, TN – 3 miles of existing two-lane highway
Planned Projects: No projects are included in Tennessee's STIP.
Assumptions: Right-of-way lies in rolling terrain, containing a mix of residential and commercial land uses.
Cost Estimate:

Table 8N
  CSD Super-2 Arterial Interstate
Engineering existing $4 million $5 million $7 million
ROW existing $3 million $4 million $5 million
Utility/Const. existing $39 million $52 million $77 million
Project Total5 existing $50 million $67 million $98 million

I-75, Charleston to Knoxville – 50 miles of six-lane Interstate planned
Planned Projects: A feasibility study prepared by TDOT recommends widening I-75 from Georgia to Kentucky before 2030.
Assumptions: No improvements included for this section.

Cost Estimate: No improvements included since the existing alignment satisfies the criteria for each of the design levels.

b. Corridor A West Dalton Spur Costs

Designers also considered creating a spur to I-75 at Dalton, eliminating the remainder of the corridor north of Chatsworth. Costs for this spur connection are shown below, divided by phase for the Interstate design level. The SR 52 provides an existing four-lane arterial connection from Chatsworth to I-75 through Dalton.

Table 9 – Dalton Spur Costs by Phase
Interstate
Engineering $16 million
ROW $28 million
Utility $17 million
Construction $103 million
Project Total $164 million

To implement Corridor A West improvements from Savannah to I-75 at Dalton is estimated to cost 13 percent to 27 percent less than the full corridor to Knoxville. Table 10 presents the total costs for both options.

Table 10 – Corridor A West and Dalton Spur Costs
  Min. Build Super-2 Arterial Interstate
A West
to Knoxville
$701 million $1.2 billion $2.5 billion $4.8 billion
A West
to Dalton
$564 million $874 million $2.0 billion $4.2 billion

c. Corridor B and B Bypass Costs

Corridor B follows SR 21 (Savannah River Parkway) from Savannah to south of Millen where it joins with Corridor A. A bypass option west of the existing SR 21 alignment allows the corridor to avoid congestion from Savannah to Springfield. Figure 10 illustrates the location of the corridor and associated costs for the arterial and Interstate design levels.

Planned Projects: A corridor study is underway by GDOT and the Chatham County-Savannah Metropolitan Planning Commission to determine the best ways to enhance mobility and livability along this key thoroughfare. It is not considered a committed project since funding is not allocated in the current Georgia STIP.

To upgrade Corridor B along SR 21 from Savannah to Millen to an interstate is anticipated to cost $398 million.  To upgrade the corridor and create an arterial or Interstate bypass of congested sections of SR 21 is anticipated to cost $576 million to $1.3 billion respectively.

Assumptions: Right-of-way is urban and contains a mix of residential and commercial uses.
Cost Estimate:

Table 11 – Costs: Corridor B and B Bypass
  Arterial Interstate
Corridor B (Savannah to Augusta)
Engineering existing $58 million
ROW existing $71 million
Utility existing $95 million
Construction existing $174 million
Project Total existing $398 million
Corridor B Bypass (Savannah to Augusta)
Engineering $58 million $128 million
ROW $183 million $273 million
Utility $29 million $73 million
Construction $306 million $805 million
Project Total $576 million $1.28 billion

Total costs to implement Corridor B or B Bypass along with the northern portion of Corridor A West are shown in Table 12 for the entire corridor length from Savannah to Knoxville.

Table 12 – Corridor B and B Bypass Costs
  Min. Build Super-2 Arterial Interstate
Corridor A West $701 million $1.2 billion $2.5 billion $4.8 billion
Corridor B/A West $701 million $1.2 billion $2.5 billion $5.2 billion
Corridor B Bypass/ A West $701 million $1.2 billion $3.1 billion $5.9 billion

d. No Build (Signing Only) Costs

The No Build option would cost significantly less than the other corridors considered. An 8-foot by 4-foot panel sign costs approximately $525. Depending on the route selected, number of signs required, and complexity of the branding, this alternative could be implemented for less than $500,000, including costs for planning, coordination, design, materials, and installation.

5.4 Uncertainties and Risk

Risk is a major concern which should be addressed in all cost estimates. Because corridors have only been developed at a conceptual level, a large number of unknown factors can have a significant impact on the overall project costs shown. The discussion below highlights categorical risks that are likely to influence project costs.

Project lacks clear definition. Prior to design tasks, the actual work involved in completing corridor improvements is undefined. For this conceptual study, costs are based solely on statewide averages and the project length. There has been no systematic analysis of existing needs or deficiencies to identify existing geometric issues along highway segments or at intersections that may require improvements. If any project segments are identified for additional development, this type of uncertainty will decrease as the project is more clearly defined, as shown in Figure 11.

Inflation. Each year, inflation decreases the buying power of the dollar. As a result, prices for goods and services tend to increase annually. Typically, inflation is estimated as a 2 to 4 percent increase per year. Not accounting for any other risk factors, a $1 billion project in 2010 will cost $1.3 billion by 2020 and $1.8 billion by 2030 at a 3 percent inflation rate.

Delays in implementation. Due to the size and complexity of the corridor, there is a high probability for schedule delays if any projects in the corridor are identified for implementation. Delays can occur due to a number of reasons:

A typical highway project can take at least 12 years to advance through the project development process from an idea to an operational facility; larger or more controversial projects are likely to take longer. Delays can have sizeable impacts on project costs, due to inflation and other factors which escalate costs over time.

To upgrade Corridor B along SR 21 from Savannah to Millen to an interstate is anticipated to cost $398 million.  To upgrade the corridor and create an arterial or Interstate bypass of congested sections of SR 21 is anticipated to cost $576 million to $1.3 billion respectively.

Indirect risks. Changes in global economies and political climates can also lead to uncertainties which affect project costs. In the last 5 years, the construction industry has seen high volatility in the construction price index driven by the building boom in Asia. The recent recession has seemed to dampen this volatility somewhat. Oil prices, steel demands in growing nations, declining gas tax revenues, and myriad other factors can impact projects.

Costs represent a high-level starting point and could be significantly higher if any projects are identified for implementation.

In light of these uncertainties, the planning-level costs presented above should be interpreted as a starting point. Contingency factors built into the estimates – 10 to 30 percent of the total cost – help account for some of these risk elements. Despite built-in contingencies, costs could be significantly higher if any projects within the corridor are identified for implementation.

5.5 Costs and Year of Expenditure

In light of the high level of uncertainty inherent in this conceptual feasibility study, costs shown below for the four build alternatives are rounded to the nearest hundred million dollars. Per TDOT standard practice, a 3.6 percent annual inflation rate has been applied to costs presented earlier in this chapter. Because a timeline has not been defined for any projects which could be identified from this study, Table 13 below presents estimated costs in year of expenditure dollars for a range of dates. As discussed in the previous section, these costs represent high-level estimates which are subject to numerous uncertainties and external factors that can greatly influence actual costs. Estimates presented represent an order of magnitude, showing how implementation delays and inflation can influence costs.


1 Additional 10% contingency added to total project costs within Tennessee

2 NEPA requires Federal agencies to prepare detailed statements assessing the environmental impact of and alternatives to actions, with an emphasis on interdisciplinary coordination between agencies. Section 404 of the Clean Water Act allows the U.S. Army Corps of Engineers to issue permits to discharge any dredged or fill materials into navigable waterways once certain public notice requirements are satisfied. Section 7 of the Endangered Species Act requires Federal agencies to ensure their actions will not jeopardize threatened/endangered species or critical habitats. Section 106 of the National Historic Preservation Act defines a process for agencies, preservation groups, and other stakeholders to balance historic preservation concerns against the needs of Federal undertakings.

Updated: 03/22/2013
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