Atlanta North-South Tunnel Feasibility Study · Atlanta North-South Tunnel Feasibility Study ......

Atlanta North-South Tunnel

Feasibility Study

Phase 1 – Initial Feasibility Study

Executive Summary

Prepared for:

Georgia Department of Transportation

Office of Innovative Program Delivery

One Georgia Center

600 West Peachtree NW

Atlanta, Georgia

Prepared by:

HNTB Corporation

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1.0 Executive Summary

1.1 Introduction

The Atlanta Region has experienced significant growth in recent decades. Total

population in the Atlanta Metro area was approximately 2.6 million in 1980, 3.3 million in

1990, and 4.5 million by the year 2000, according to the U.S. Census Bureau.

Transportation infrastructure investment has not kept pace with this rapid growth,

resulting in increased congestion on the region’s roadways, and increased travel times

throughout the region.

One particular corridor that has experienced significant growth in c

75/I-85 Downtown Connector, which provides north

Atlanta core. Opportunities for increasing capacity along this corridor are limited, due in

part to its close proximity to dense urban land uses. In addition,

not access controlled, and do not offer adequate capacity to attract a significant number

of vehicles away from the Downtown Connector. Few options exist for improving

existing facilities to a level that could stem the tide of risi

of large-scale infrastructure investment, future growth in the region will only exacerbate

existing north-south mobility problems in Atlanta.

One potential solution to increased north

provide an alternative, limited

Downtown Connector. The Atlanta North

“Tunnel”), as defined in this

would provide a connection between th

675/I-285.

The idea of providing a north

proposed decades ago. Originally envisioned as a surface roadway, intense

development along this alignment over time has rendered such an alternative

infeasible. The Georgia Department of Transportation has initiated this study to

examine the feasibility of a north

congestion in Atlanta’s urban core

1.2 Purpose

The purpose of this study was to determine the overall feasibility of the Atlanta North

South Tunnel. This was accomplished through an evaluation of

revenue potential, and project

operation and maintenance costs, etc.)

Tunnel is viable as a stand

as a solicited public-private

Atlanta North-South Tunnel Feasibility Report

Executive Summary

Introduction




rtation infrastructure investment has not kept pace with this rapid growth,


One particular corridor that has experienced significant growth in congestion is the I

85 Downtown Connector, which provides north-south movement through the


part to its close proximity to dense urban land uses. In addition, parallel facilities are



existing facilities to a level that could stem the tide of rising congestion. In the absence

scale infrastructure investment, future growth in the region will only exacerbate

south mobility problems in Atlanta.

One potential solution to increased north-south congestion levels in Atlanta would b

provide an alternative, limited-access facility to act as a parallel reliever to the

Downtown Connector. The Atlanta North-South Tunnel (also referred to as the

“Tunnel”), as defined in this feasibility study, would serve as such a link. This facili

would provide a connection between the existing interchanges at SR 400

The idea of providing a north-south connection between these interchanges was first

proposed decades ago. Originally envisioned as a surface roadway, intense



examine the feasibility of a north-south tunnel to provide needed mobility and relieve

tion in Atlanta’s urban core.

The purpose of this study was to determine the overall feasibility of the Atlanta North

South Tunnel. This was accomplished through an evaluation of travel demand

and project costs (including construction costs, Right

operation and maintenance costs, etc.). The objective of this analysis was

Tunnel is viable as a stand-alone, toll-financed project that could potentially be procured

private partnership (P3). Additionally, social and environmental

South Tunnel Feasibility Report August 2010




rtation infrastructure investment has not kept pace with this rapid growth,


ongestion is the I-

south movement through the


parallel facilities are



ng congestion. In the absence

scale infrastructure investment, future growth in the region will only exacerbate

south congestion levels in Atlanta would be to

access facility to act as a parallel reliever to the

South Tunnel (also referred to as the

study, would serve as such a link. This facility

400/I-85 and I-

south connection between these interchanges was first

proposed decades ago. Originally envisioned as a surface roadway, intense land



south tunnel to provide needed mobility and relieve

The purpose of this study was to determine the overall feasibility of the Atlanta North-

travel demand,

ight-of-Way costs,

. The objective of this analysis was to see if the

financed project that could potentially be procured

). Additionally, social and environmental

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costs and benefits have been

evaluate whether or not public funding should be used to close the potential funding

gap, should a funding gap exist

Key study outcomes include a

revenue, detailed cost estimates, financial assessment, and a high

project constructability. Taken together, these elements provide a comprehensive

picture of the challenges and opportunities associated with development of the Atlanta

North-South Tunnel. This report also provides a roadmap for next steps if GDOT

decides to proceed further with Tunnel development.

1.3 Methodology

1.3.1 Phased Approach

A phased approach wa

baseline criteria were established for basic costing and scheduling. In Phase 1B

base assumptions were refined, including improvement to intersection

configuration and alignment, and improvement to overal

These reductions in construction time and construction costs were then taken

into account in the application of the financial model. This report details only

those activities in Phases 1A and 1B.

If GDOT elects to move forward i

activities identified for Phase 2. These would include aerial mapping and

subsurface investigation

investigation of financing methods and the establishment of

the project.

1.3.2 Tunnel Demand and Revenue

In Phase 1A HNTB

understand the market for

its revenue generating potential. The travel de

divided into two stages:

In Stage 1, HNTB

assuming no tolls on the facility. HNTB

from a series of design variables under th

generated a set of “base case” design parameters to be used in the subsequent

revenue analysis.

In Stage 2, HNTB sought t

potential of the facility. The “base case” design paramete


have been considered in overall cost-benefit analyses to help


gap, should a funding gap exist.

Key study outcomes include a preliminary-level estimate of tunnel demand and

revenue, detailed cost estimates, financial assessment, and a high-level analysis of


the challenges and opportunities associated with development of the Atlanta

South Tunnel. This report also provides a roadmap for next steps if GDOT

decides to proceed further with Tunnel development.

Methodology

Phased Approach

A phased approach was used in the execution of this study. In Phase 1A



configuration and alignment, and improvement to overall construction scheduling.



those activities in Phases 1A and 1B.

If GDOT elects to move forward in the study process, there are a number of


subsurface investigations, along with refined revenue and cost estimates, and

investigation of financing methods and the establishment of a legal framework for

Tunnel Demand and Revenue

In Phase 1A HNTB conducted a travel demand and revenue analysis to

understand the market for the proposed Atlanta North-South Tunnel,

generating potential. The travel demand and revenue

divided into two stages:

HNTB sought to understand the “pure demand” for the Tunnel,

assuming no tolls on the facility. HNTB analyzed the impact to travel demand

from a series of design variables under this “toll free” assumption. This analysis


revenue analysis.

In Stage 2, HNTB sought to determine the maximum revenue generating

potential of the facility. The “base case” design parameters were applied while


benefit analyses to help


unnel demand and

level analysis of


the challenges and opportunities associated with development of the Atlanta

South Tunnel. This report also provides a roadmap for next steps if GDOT

s used in the execution of this study. In Phase 1A



l construction scheduling.



n the study process, there are a number of


, along with refined revenue and cost estimates, and

a legal framework for

conducted a travel demand and revenue analysis to

South Tunnel, along with

mand and revenue analysis was

the “pure demand” for the Tunnel,

analyzed the impact to travel demand

free” assumption. This analysis


generating

rs were applied while

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the toll rates were varied to determine the set of toll rates for which maximum

revenue generation occurs. These same toll rates were later applied to

alternative design parameters to assess the impact these new parameters would

have on revenue.

In addition to the analysis of the Tunnel itself, HNTB also studied alternatives

with the potential to improve

4-mile spur connecting the northern terminal of the Tunnel directly to I

of the Brookwood interchange with I

application of variable toll rates along SR 400 ins

toll facility connecting the northern and southern ends of I

would provide supplemental income for the Tunnel and potentially improve the

project’s financial feasibility.

The primary tool used by

the Tunnel was the

(ARC) regional travel demand model

2030 Envision 6 model almost exclusively; ARC’s Year 2020

was used occasionally for comparison purposes and to help develop gross

revenue streams. These revenue streams were generated for various

design and operational alternatives, and were then used as input in a financial

model that helped determine the extent to which the facility would be self

financing.

1.3.3 Cost

The other key component in the financial feasibility assessment was the

estimation of costs. Preparing a reliable cost estimate for the construction of a

tunnel is a complex

cost of the project is tied to specific job characteristics. Underground

construction costs are heavily influenced by subsurface conditions, labor market

and construction means and methods. Tho

tunnel construction to the other. The HNTB team developed the Atlanta North

South Tunnel cost estimates using a “bottom

the ground conditions based on available documents, and also assessed

production rates based on previous underground construction in Atlanta. Those

data gathered for the project coupled with a conceptual design for the facility

enabled the team to prepare the basis for a bottom

Several different cost elements wer

Construction costs, engineering costs, and operations and maintenance cos

were calculated for various t

accounted for based on estimates for the construction timeframe. C

were also applied to various cost elements, including tunnel construction,





on revenue.


with the potential to improve overall tunnel feasibility. The first alternative was a

mile spur connecting the northern terminal of the Tunnel directly to I

of the Brookwood interchange with I-85. Another alternative involved the

application of variable toll rates along SR 400 inside I-285, creating a continuous

toll facility connecting the northern and southern ends of I-285. Both alternatives


project’s financial feasibility.

used by HNTB to evaluate demand and revenue potential for

the most recent version of the Atlanta Regional Commission’s

(ARC) regional travel demand model. The demand analysis utilized the Year

6 model almost exclusively; ARC’s Year 2020 Envision


revenue streams. These revenue streams were generated for various


elped determine the extent to which the facility would be self

Cost

other key component in the financial feasibility assessment was the


tunnel is a complex process. For underground construction in general, the final



and construction means and methods. Those factors vary widely from one

tunnel construction to the other. The HNTB team developed the Atlanta North

South Tunnel cost estimates using a “bottom-up” approach. The team assessed


roduction rates based on previous underground construction in Atlanta. Those


enabled the team to prepare the basis for a bottom-up estimate.

Several different cost elements were estimated as part of this study.

Construction costs, engineering costs, and operations and maintenance cos

were calculated for various tunnel alternatives. In addition, inflation was

accounted for based on estimates for the construction timeframe. C







unnel feasibility. The first alternative was a

mile spur connecting the northern terminal of the Tunnel directly to I-75, north

85. Another alternative involved the

285, creating a continuous

285. Both alternatives


valuate demand and revenue potential for

Atlanta Regional Commission’s

. The demand analysis utilized the Year

Envision 6 model


revenue streams. These revenue streams were generated for various tunnel


elped determine the extent to which the facility would be self-

other key component in the financial feasibility assessment was the


process. For underground construction in general, the final



se factors vary widely from one

tunnel construction to the other. The HNTB team developed the Atlanta North-

up” approach. The team assessed


roduction rates based on previous underground construction in Atlanta. Those


e estimated as part of this study.

Construction costs, engineering costs, and operations and maintenance costs

unnel alternatives. In addition, inflation was

accounted for based on estimates for the construction timeframe. Contingencies


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elevated structures,

costs.

1.3.4 Other Key Considerations

Revenue and costs were the key determinants of overall financial

the Atlanta North-

and cost estimates, including facility location and design details. Factors that

influenced the financial feasibility determination are outlined in this section

are described in more detail in the body of the report.

The preferred alignment and

as part of this study. These both had direct impacts on project cost and

environmental assessment. Objectives as

development included minimizing the length and cost of the route, along with

limiting social and environmental impacts. Typical cross

established for the Tunnel, including the

structures, and emergency egress structures. These cross

facilitate the Tunnel cost estimates, as well as the constructability and

environmental assessments.

Other key elements that were examined as part of this study inc

facilities and subsurface conditions. As a complex project, the Atlanta North

South Tunnel requires a number of supporting systems in order to function

properly. Care was taken in this study to document details relevant to these

systems, and to account for all related industry standards regarding their

development, in order to calculate a more accurate cost estimate. Specific

systems included in this study are ventilation, fire/life/safety, tunnel management

systems, control systems, lighting

In addition to these supporting systems, HNTB also performed a desk study to

investigate the geology and geotechnical conditions along the proposed

alignment. Information from this desk study served as anoth

determining project constructability and in estimating project costs.

1.4 Results and

1.4.1 Tunnel Demand and Revenue

HNTB studied a number of project alternatives as part of the demand analysis for

the Atlanta North-

were examined, as were truck restrictions and truck eligibility. HNTB also

investigated the impacts of various posted speed limits and number of lanes on

overall tunnel demand.


elevated structures, Right-of-Way costs, and engineering and management

Other Key Considerations

Revenue and costs were the key determinants of overall financial

-South Tunnel. A number of factors drove the tunnel revenue


influenced the financial feasibility determination are outlined in this section

are described in more detail in the body of the report.

The preferred alignment and a preliminary profile of the Tunnel were determined


environmental assessment. Objectives associated with the alignment and profile


limiting social and environmental impacts. Typical cross-sections were also

established for the Tunnel, including the tunnel mainline, ramps, approach

structures, and emergency egress structures. These cross-sections also helped


environmental assessments.

Other key elements that were examined as part of this study include system

facilities and subsurface conditions. As a complex project, the Atlanta North



to account for all related industry standards regarding their



systems, control systems, lighting and power design, and architectural finishes.



alignment. Information from this desk study served as another key element in


Results and Findings

Tunnel Demand and Revenue


-South Tunnel. Various access points and access locations



overall tunnel demand.


ay costs, and engineering and management

Revenue and costs were the key determinants of overall financial feasibility for

unnel revenue


influenced the financial feasibility determination are outlined in this section and

profile of the Tunnel were determined


sociated with the alignment and profile


sections were also

ps, approach

sections also helped


lude system

facilities and subsurface conditions. As a complex project, the Atlanta North-



to account for all related industry standards regarding their



and power design, and architectural finishes.



er key element in



access points and access locations



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Efforts from this demand analysis resulte

assumptions that were used in subsequent tolling analysis. It was found that a

pipeline configuration (i.e. no intermediate

85 and I-675/I-285 interchanges) generated strong demand, while t

of intermediate access increased utilization

configuration was carried forward as a base case assumption. The analysis of

number of lanes showed diminishing returns in providing additional capacity.

For this reason, a base case assumption of 2 lanes in each direction was used,

while a 3-lane alternative was also tested for comparison purposes. Allowing

trucks in the Tunnel would create design and operational challenges. However,

demand analysis showed m

assumption of prohibiting trucks from the Tunnel. Finally, HNTB determined that

model free-flow speeds were an appropriate base case assumption, resulting in a

Tunnel design that would accommodate 55 mph post

In summary, the base case assumptions used for tolling analysis included:

• Pipeline configuration

• 2 lanes in each direction

• Trucks prohibited

• Model free-flow speeds (Posted speed

Following the demand analysis, HNTB conducted a

the base case assumptions for the Atlanta North

rates for the base year 2030 were determined to be

per mile (off-peak) and $0.13

maximum annual revenue

Alternative sets of tunnel design parameters

travel demand model (using the optimal toll rates established for the base case

parameters) to provide a quick evaluation of

potential. It was determined that the

intermediate access at I

3 lanes in each directi

the tunnel directly to I

Conversely, the additional

400 inside of I-285

(a revenue increase of 80% to 90%) as

implementation costs

Gross revenue streams

$1.4B, $3.0B and $5.4B

The revenue streams

respectively, if the 6.5 mile portion of


Efforts from this demand analysis resulted in a set of base case design


pipeline configuration (i.e. no intermediate access points between the

285 interchanges) generated strong demand, while t

of intermediate access increased utilization only slightly. Therefore a pipeline



this reason, a base case assumption of 2 lanes in each direction was used,

lane alternative was also tested for comparison purposes. Allowing


demand analysis showed minimal truck volumes, resulting in a base case


flow speeds were an appropriate base case assumption, resulting in a

Tunnel design that would accommodate 55 mph posted speeds.


Pipeline configuration;

2 lanes in each direction;

Trucks prohibited;

flow speeds (Posted speed = 55 - 65 mph).

Following the demand analysis, HNTB conducted a toll-sensitivity analysis using

the base case assumptions for the Atlanta North-South Tunnel. Optimal tolling

rates for the base year 2030 were determined to be $0.50 per mile

peak) and $0.13 per mile (nighttime). The optimal rates

maximum annual revenue of $38.7 million for the base year 2030 (2008 dollars)

Alternative sets of tunnel design parameters were analyzed with the refined


to provide a quick evaluation of their annual revenue generating

potential. It was determined that the additional revenue generated by

intermediate access at I-20, increasing capacity from 2 lanes in each direction

in each direction, or including an I-75 spur (to connect the north end of

the tunnel directly to I-75) did not justify the associated additional costs

additional revenue generated by tolling the 6.5 mile portion of SR

285 (at the same per mile toll rates as the Tunnel)

(a revenue increase of 80% to 90%) as compared to the associated

implementation costs, which would be minimal.

evenue streams for 30, 50 and 75-year periods were estimated to be

$1.4B, $3.0B and $5.4B (in $2008), respectively, if the Tunnel alone is tolled

The revenue streams were estimated to increase to $2.7B, $5.6B and $10.0B

the 6.5 mile portion of SR 400 inside of I-285 is tolled as well.


d in a set of base case design


access points between the SR 400/I-

285 interchanges) generated strong demand, while the provision

only slightly. Therefore a pipeline



this reason, a base case assumption of 2 lanes in each direction was used,

lane alternative was also tested for comparison purposes. Allowing


inimal truck volumes, resulting in a base case


flow speeds were an appropriate base case assumption, resulting in a


sensitivity analysis using

South Tunnel. Optimal tolling

per mile (peak), $0.25

rates generated

for the base year 2030 (2008 dollars).

were analyzed with the refined


annual revenue generating

generated by adding

in each direction to

75 spur (to connect the north end of

additional costs.

ling the 6.5 mile portion of SR

) was significant

associated

periods were estimated to be

, if the Tunnel alone is tolled.

increase to $2.7B, $5.6B and $10.0B,

is tolled as well.

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These revenue streams

determine project financeability

year period from 2023 to 2097, under base case design assumptions.

Opening year for the Tunnel was estimated to be 2023. The env

permitting process was projected to take 5 years, and the construction time

frame was estimated to be 6 years.

with the construction period, based on the delivery approach employed.

Table 1. Revenue stream for base case set of tunnel design assumptions.

Year Annual Revenue

(2008 dollars)

2023 $32,597,000

2024 $33,467,000

2025 $34,336,000

2026 $35,205,000

2027 $36,075,000

2028 $36,944,000

2029 $37,813,000

2030 $38,683,000

2031 $39,957,000

2032 $41,232,000

2033 $42,506,000

2034 $43,780,000

2035 $45,055,000

2036 $46,329,000

2037 $47,604,000

2038 $48,878,000

2039 $50,153,000

2040 $51,427,000

2041 $52,702,000

2042 $53,976,000

2043 $55,250,000

2044 $56,525,000

2045 $57,799,000

2046 $59,074,000

2047 $60,348,000


revenue streams were then used as inputs in a financial model to

determine project financeability. Table 1 shows the revenue stream for the 75


Opening year for the Tunnel was estimated to be 2023. The environmental


frame was estimated to be 6 years. Design activities would potentially overlap


Revenue stream for base case set of tunnel design assumptions.

Year Annual Revenue

(2008 dollars) Year

Annual Revenue

(2008 dollars)

2048 $61,623,000 2073 $87,600,000

2049 $62,897,000 2074 $88,139,000

2050 $64,172,000 2075 $88,678,000

2051 $65,446,000 2076 $89,217,000

2052 $66,720,000 2077 $89,756,000

2053 $67,995,000 2078 $90,295,000

2054 $69,269,000 2079 $90,834,000

2055 $70,544,000 2080 $91,373,000

2056 $71,818,000 2081 $91,912,000

2057 $73,093,000 2082 $92,451,000

2058 $74,367,000 2083 $92,990,000

2059 $75,642,000 2084 $93,529,000

2060 $76,916,000 2085 $94,068,000

2061 $78,190,000 2086 $94,607,000

2062 $79,465,000 2087 $95,146,000

2063 $80,739,000 2088 $95,685,000

2064 $82,014,000 2089 $96,224,000

2065 $83,288,000 2090 $96,763,000

2066 $83,827,000 2091 $97,295,000

2067 $84,366,000 2092 $97,831,000

2068 $84,905,000 2093 $98,369,000

2069 $85,444,000 2094 $98,910,000

2070 $85,983,000 2095 $99,454,000

2071 $86,522,000 2096 $100,001,000

2072 $87,061,000 2097 $100,551,000


were then used as inputs in a financial model to

Table 1 shows the revenue stream for the 75-


ironmental


Design activities would potentially overlap


Revenue stream for base case set of tunnel design assumptions.

Annual Revenue

(2008 dollars)

$87,600,000

$88,139,000

$88,678,000

$89,217,000

$89,756,000

$90,295,000

$90,834,000

$91,373,000

$91,912,000

$92,451,000

$92,990,000

$93,529,000

$94,068,000

$94,607,000

$95,146,000

$95,685,000

$96,224,000

$96,763,000

$97,295,000

$97,831,000

$98,369,000

$98,910,000

$99,454,000

$100,001,000

$100,551,000

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1.4.2 Cost and Financeability

HNTB estimated constr

• Alternate 1A: Twin tunnel, two lanes each direction with no intermediate

access (Phase 1A was the original cost estimate and Phase 1B was a

revised estimate resulting from a value engineer

• Alternate 1B: Twin tunnel, two lanes each direction with I

• Alternate 2A: Twin tunnel, three lanes each direction with no intermediate

access;

• Alternate 2B: Twin tunnel, three lanes each direction with I

• Alternate 3A: One stacked tunnel, two lanes each direction with no

intermediate access

• Alternate 3B: One stacked tunnel, two lanes each direction with I

interchange.

Table 2 highlights cost details associated with alternates 1A and 1B. Costs for

alternates 2A, 2B, 3A, and 3B were also developed as part of this study.

However, these were removed from further consideration because the increased

costs were not offset

Table 2. Project cost estimate for different alternatives (cost is

Alternates

Base Construction

ROW

Estimated E&C

Contingency ($)

Design and Permits (years)

Const. Duration

Total Escalated

Project Cost


Cost and Financeability

estimated construction costs for the following tunnel alternatives:

Alternate 1A: Twin tunnel, two lanes each direction with no intermediate


revised estimate resulting from a value engineering exercise)

Alternate 1B: Twin tunnel, two lanes each direction with I-20 interchange

Alternate 2A: Twin tunnel, three lanes each direction with no intermediate

Alternate 2B: Twin tunnel, three lanes each direction with I-20 interchange

Alternate 3A: One stacked tunnel, two lanes each direction with no

intermediate access;

Alternate 3B: One stacked tunnel, two lanes each direction with I

highlights cost details associated with alternates 1A and 1B. Costs for



costs were not offset by increases in benefits or revenue.

Project cost estimate for different alternatives (cost is in $1000) in 2009 Dollars.

1A

(Phase 1B) 1A

(Phase 1A) 1B

$1,725,882 $2,455,190 $2,955,446

$75,000 $142,616 $193,936

Estimated E&C $374,176 $519,561 $629,876

Contingency ($) $364,849 $623,473 $755,852

Permits (years) 5 years 5 years 6 years

Const. Duration 6 years 8 years 9 years

$3,172,681 $4,860,199 $6,152,610


unnel alternatives:

Alternate 1A: Twin tunnel, two lanes each direction with no intermediate


ing exercise);

20 interchange;

Alternate 2A: Twin tunnel, three lanes each direction with no intermediate

20 interchange;

Alternate 3A: One stacked tunnel, two lanes each direction with no

Alternate 3B: One stacked tunnel, two lanes each direction with I-20

highlights cost details associated with alternates 1A and 1B. Costs for



2009 Dollars.

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Capital cost estimates were combined with operations and maintenance cost

estimates and included as inputs in the financial model. For Alternate 1A,

assuming a $3.2B cost and gross revenue estimates as described previously,

output from the financial model indicates a necessary public subsidy of

approximately $2.4B. GDOT’s total annual budget in recent years has averaged

less than $2.0B. Therefore, securing the needed gap funding poses a significant

challenge.

1.4.3 Constructability

While project financing poses challenges for implementation, the Atlanta North

South Tunnel does appear to be feasible from a constructability standpoint. The

proposed tunnel alignment provides connection between the northern terminus at

the SR 400/I-85 interchange an

interchange, following an alignment west and parallel to Moreland Avenue. This

alignment is approximately 11 miles long, with a combination of 6 miles of tunnel

and 5 miles of at-grade construction. Lane widths

with inside and outside shoulder widths of 2

clearance of the Tunnel is 14

HNTB has determined that the mainline tunnels could be constructed with a

tunnel boring machine (TBM). Use of a TBM wou

excavation along the proposed project alignment, which consists of hard,

massive, abrasive metamorphic rock with granitic intrusions. Approaches to the

Tunnel on both the northern and southern ends will consist of U

(trenches), followed by twin cut

tunnels.

Based on the review conducted in Phase 1B of the study, it was determined that

much of the mechanical and electrical systems equipment could be located in

near-surface, underground structures. Intermediate ventilation plant buildings

will also be required along the project length, but with smaller footprints than

originally projected.

ventilation to jet fans.

indicated that a footprint of approximately 160 f

Revised estimates from Phase 1B indicate that this could be reduced to 50 f

by 105 feet.

One of the most fortuitous fi

constraints exist along the proposed alignment

of a tunnel. While an Environmental Impact Statement will likely be required in

order to move forward with design and construction, preliminary analysis

suggests that there are no insurmountable challenges related to environmental

clearance.





financial model indicates a necessary public subsidy of



Constructability

financing poses challenges for implementation, the Atlanta North



85 interchange and the southern terminus at the I-675/I



grade construction. Lane widths are proposed to be 12

with inside and outside shoulder widths of 2 feet. The proposed vertical

clearance of the Tunnel is 14 feet.


tunnel boring machine (TBM). Use of a TBM would be appropriate for the



Tunnel on both the northern and southern ends will consist of U-S

ches), followed by twin cut-and-cover boxes, and followed by twin starter



derground structures. Intermediate ventilation plant buildings

be required along the project length, but with smaller footprints than

projected. This is due primarily to a shift in design from standard

ventilation to jet fans. Phase 1A estimates for the ventilation plant buildings

indicated that a footprint of approximately 160 feet by 130 feet would be required.

Revised estimates from Phase 1B indicate that this could be reduced to 50 f

One of the most fortuitous findings in this analysis was that no physical

exist along the proposed alignment that would preclude construction

. While an Environmental Impact Statement will likely be required in







financial model indicates a necessary public subsidy of



financing poses challenges for implementation, the Atlanta North-



675/I-285



are proposed to be 12 feet

The proposed vertical


ld be appropriate for the



Sections

cover boxes, and followed by twin starter



derground structures. Intermediate ventilation plant buildings

be required along the project length, but with smaller footprints than

This is due primarily to a shift in design from standard

1A estimates for the ventilation plant buildings

t would be required.

Revised estimates from Phase 1B indicate that this could be reduced to 50 feet

physical

that would preclude construction

. While an Environmental Impact Statement will likely be required in



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The Atlanta North

public education and outreach with GDOT, other government agencies, project

stakeholders, neighborhood groups and the general public throughout project

development. Concerns related this project w

order to avoid hurdles later in the development phases.

1.5 Benefits

The Atlanta North-South Tunnel is projected to generate approximately $2.2 Billion

($2008) in gross revenue over 30 years from 2023 to 2052. This

short of fully financing the project, but does provide support for the issuance of toll

backed debt to pay for a portion of capital

maintenance. The benefits of the Tunnel

generating potential. Indeed, an investment of this size has local and even regional

transportation impacts which are described in more detail in this

several of these benefits, including the reduction in vehicl

savings in time and fuel. Consideration was also given to improvement in travel time

index on major roadways and to emission reductions. Finally, regional economic

benefits and projected job creation were also calculated as part of

Tunnel-related benefits.

The Tunnel draws vehicles that would otherwise use alternate routes. This frees up

capacity on these facilities and reduces the delay that users experience. The Tunnel

has a significant impact on the Downtown Co

by 30% in year 2030. It also attracts vehicles from I

daily vehicle delay on the West Wall of I

In 2030, nearly 20 million vehicle h

to the addition of the Tunnel. This amounts to 2.5% of the regional total. Over the 75

year period between 2023 and 2097, the Tunnel provides cumulative delay savings of

over 2.8 Billion hours.

The Tunnel’s impact on vehicle delay can also be translated into dollar savings, based

on the value of time of transportation system users, and fuel savings, based on fuel burn

rates as a result of congested conditions. The time savings realized on the Downtow

Connector alone are over $110 million just in year 2030. Regional savings in 2030 are

nearly one-third of a billion dollars. Cumulative savings for the entire region over the 75

year period between 2023 and 2097 are nearly $50 Billion. Fuel savings fo

the Downtown Connector reach almost 4.5 million gallons in year 2030. Over 13 million

gallons are saved region wide in 2030, and the cumulative regional savings over the 75

year period between 2023 and 2097 is nearly 2 billion gallons.

The fuel savings described above has a positive impact on air quality and greenhouse

gas emissions. Every gallon of gas that is saved reduces air pollutants, including carbon


The Atlanta North-South Tunnel is an unprecedented undertaking that will require



development. Concerns related this project will need to be addressed early in

order to avoid hurdles later in the development phases.

South Tunnel is projected to generate approximately $2.2 Billion

in gross revenue over 30 years from 2023 to 2052. This level of revenue falls

short of fully financing the project, but does provide support for the issuance of toll

backed debt to pay for a portion of capital expenditures and ongoing operations and

he benefits of the Tunnel, however, are not limited to its revenue


transportation impacts which are described in more detail in this report.

several of these benefits, including the reduction in vehicle delay and subsequent



benefits and projected job creation were also calculated as part of the analysis of



has a significant impact on the Downtown Connector, effectively reducing vehicle delay

by 30% in year 2030. It also attracts vehicles from I-285, resulting in a 7% reduction in

daily vehicle delay on the West Wall of I-285 and a 9% reduction on the East Wall.

In 2030, nearly 20 million vehicle hours of delay are eliminated in the Atlanta region due



unnel’s impact on vehicle delay can also be translated into dollar savings, based


rates as a result of congested conditions. The time savings realized on the Downtow


third of a billion dollars. Cumulative savings for the entire region over the 75

year period between 2023 and 2097 are nearly $50 Billion. Fuel savings fo



year period between 2023 and 2097 is nearly 2 billion gallons.

fuel savings described above has a positive impact on air quality and greenhouse



h Tunnel is an unprecedented undertaking that will require



ill need to be addressed early in

South Tunnel is projected to generate approximately $2.2 Billion

level of revenue falls

short of fully financing the project, but does provide support for the issuance of toll-

expenditures and ongoing operations and

mited to its revenue


HNTB examined

e delay and subsequent



the analysis of



nnector, effectively reducing vehicle delay

285, resulting in a 7% reduction in

285 and a 9% reduction on the East Wall.

ours of delay are eliminated in the Atlanta region due



unnel’s impact on vehicle delay can also be translated into dollar savings, based


rates as a result of congested conditions. The time savings realized on the Downtown


third of a billion dollars. Cumulative savings for the entire region over the 75

year period between 2023 and 2097 are nearly $50 Billion. Fuel savings for travelers on



fuel savings described above has a positive impact on air quality and greenhouse


-10-

monoxide (CO), various oxides of nitrogen (NO

(VOC) that would otherwise have formed in the atmosphere. Gas savings also reduces

the amount of carbon dioxide (CO

Environmental Protection Agency, HNTB calculated the benefits to air quality and

emissions as a result of the Tunnel. 190,000 metric tons of CO, 17,000 metric tons of

NOx, and 25,000 metric tons of VOC are kept out of the atmosphere in year 2030 in the

20-county Atlanta region as a result of the Tunnel. In addition, nearly 115,000 metric

tons of CO2 are kept out of the atmosphere in year 2030. This is equivalent to a CO

reduction resulting from 8% of the metro Atlanta workforce telecommuting one day a

week for the entire year.

HNTB also calculated the travel time index on the Downtown Connector,

without the Tunnel. These results are presented in

ratio of peak period travel time along a corridor to off

A value of 1 indicates that it takes the same amount of time to travel a corridor in the

peak and off-peak times. A value of 2

corridor in the peak period than it does in the off

decreases these values by 18% and 23% to 4.52 and 3.65, for the Southbound and

Northbound directions.

Table 3. Travel Time Index on the Downtown Connector

(Peak Travel Time/Off-Peak Travel Time)

Without Tunnel

With Tunnel

Accumulated benefits over the life

terms, and in terms of job creation. Using the same assumption for value of time that

was used previously, the Tunnel is projected to generate $25 billion in economic benefit

to the Atlanta region over

creation assumptions from the

of financial investment, the Tunnel will be directly responsible for the creation of 14,000

jobs. Using assumptions for direct, indirect, and induced effects associated with the

$3.2 billion Tunnel project, nearly 60,000 jobs could be created.

South Tunnel would generate significant

These benefits come in the form of time and fuel savings, and in environmental

preservation. Using GDOT’s

Tunnel was calculated to be

considered. If region-wid


monoxide (CO), various oxides of nitrogen (NOX), and volatile organic compounds

) that would otherwise have formed in the atmosphere. Gas savings also reduces

the amount of carbon dioxide (CO2) in the atmosphere. Using assumptions from the


a result of the Tunnel. 190,000 metric tons of CO, 17,000 metric tons of


county Atlanta region as a result of the Tunnel. In addition, nearly 115,000 metric

are kept out of the atmosphere in year 2030. This is equivalent to a CO


HNTB also calculated the travel time index on the Downtown Connector,

without the Tunnel. These results are presented in Table 3. The travel time index is the

ratio of peak period travel time along a corridor to off-peak travel time along that corridor.


peak times. A value of 2 indicates that it takes twice as long to travel a

corridor in the peak period than it does in the off-peak, etc. The addition of the Tunnel


Time Index on the Downtown Connector

Peak Southbound (PM Peak Direction)

Northbound (AM Peak Direction)

5.49 4.72

4.52 3.65

Accumulated benefits over the life of the project were also generated in both financial



to the Atlanta region over 75 years. Estimates for job creation vary widely. Using job

creation assumptions from the U.S Department of Labor, along with the projected level


mptions for direct, indirect, and induced effects associated with the

$3.2 billion Tunnel project, nearly 60,000 jobs could be created. The Atlanta North

generate significant transportation benefits for the Atlanta region.

ts come in the form of time and fuel savings, and in environmental

preservation. Using GDOT’s Benefit Cost Analysis Worksheet, the B/C ratio of the

was calculated to be 2.22, if only benefits to the Downtown Connector are

wide delay benefits are taken into account, the ratio is 6.67.


), and volatile organic compounds

) that would otherwise have formed in the atmosphere. Gas savings also reduces

) in the atmosphere. Using assumptions from the


a result of the Tunnel. 190,000 metric tons of CO, 17,000 metric tons of


county Atlanta region as a result of the Tunnel. In addition, nearly 115,000 metric

are kept out of the atmosphere in year 2030. This is equivalent to a CO2


HNTB also calculated the travel time index on the Downtown Connector, both with and

. The travel time index is the

peak travel time along that corridor.


indicates that it takes twice as long to travel a

peak, etc. The addition of the Tunnel


Northbound (AM Peak Direction)

of the project were also generated in both financial



75 years. Estimates for job creation vary widely. Using job

U.S Department of Labor, along with the projected level


mptions for direct, indirect, and induced effects associated with the

Atlanta North-

the Atlanta region.

ts come in the form of time and fuel savings, and in environmental

B/C ratio of the

, if only benefits to the Downtown Connector are

e delay benefits are taken into account, the ratio is 6.67.

-11-

1.6 Next steps

This study serves as an initial screen of the feasibility of constructing the Atlanta North

South Tunnel. The study concentrated on the technical aspects of project

implementation, with particular focus on revenue

constructability. Throughout the study,

implementation to provide the most financially feasible project possible.

GDOT must now make the go/no

implementation based on the project’s merits, associated investment costs, and funding

landscape. If the Department does decide to move forward, a number of key steps will

be required. Some of these steps are ou

included in the body of the report.

One key next step for GDOT is public outreach. In order to achieve widespread buy

for this project, GDOT should perform one

planning partners in the Atlanta region. These one

platform for general discussion surrounding the Atlanta North

briefing of the work conducted to date, and provide a venue for solicited feedback from

state and local officials.

Conversations with representatives from the following agencies would prime the pump

for subsequent efforts in project development. GDOT should arrange meetings with the

Federal Highway Administration (FHWA), Georgia State Road and To

(SRTA), Georgia Regional Transportation Authority (GRTA), Atlanta Regional

Commission (ARC), Metropolitan Atlanta Rapid Transit Authority (MARTA), Transit

Implementation Board (TIB), Metro Atlanta Chamber of Commerce (MACOC), the City of

Atlanta, Fulton County, DeKalb County and key neighborhood groups. Feedback should

also be solicited from the Georgia Governor’s Office and local and state elected officials.

Following one-on-one meetings with representatives

committee should be established, which would be comprised of regional transportation

leaders from the agencies listed above, and from others in the community. This

committee will be a forum for communicating regional issues and concerns related to the

Tunnel, and for identifying opportunities that may have yet to be explored. The

committee would also provide recommendation for

over the life of environmental documentation and design activities, if the project is

advanced.

Stakeholder outreach and acceptance is critical if GDOT determines to move

with the Atlanta North-South Tunnel. If it is decided that the project will be advanced, a

number of additional efforts would need to be initiated. GDOT should retain an

environmental consultant in order to proceed with required environmental documentation

in accordance with NEPA guidelines. GDOT must also create a project number and

dedicate money for Right


Next steps

This study serves as an initial screen of the feasibility of constructing the Atlanta North


h particular focus on revenue generating potential, costs, and

constructability. Throughout the study, efforts were made to optimize tunnel


GDOT must now make the go/no-go decision regarding whether to proceed with



be required. Some of these steps are outlined below and additional discussion is

included in the body of the report.

One key next step for GDOT is public outreach. In order to achieve widespread buy

for this project, GDOT should perform one-on-one outreach with key stakeholders and

partners in the Atlanta region. These one-on-one meetings would serve as a

platform for general discussion surrounding the Atlanta North-South Tunnel, allow for a




Federal Highway Administration (FHWA), Georgia State Road and Tollway Authority




lanta, Fulton County, DeKalb County and key neighborhood groups. Feedback should


one meetings with representatives from these agencies





provide recommendation for the project development process


Stakeholder outreach and acceptance is critical if GDOT determines to move

South Tunnel. If it is decided that the project will be advanced, a




Right-of-Way acquisition and Preliminary Engineering (PE)


This study serves as an initial screen of the feasibility of constructing the Atlanta North-


generating potential, costs, and

unnel


n regarding whether to proceed with tunnel



tlined below and additional discussion is

One key next step for GDOT is public outreach. In order to achieve widespread buy-in

one outreach with key stakeholders and

one meetings would serve as a

South Tunnel, allow for a




llway Authority




lanta, Fulton County, DeKalb County and key neighborhood groups. Feedback should


from these agencies, a stakeholder





the project development process


Stakeholder outreach and acceptance is critical if GDOT determines to move forward

South Tunnel. If it is decided that the project will be advanced, a




acquisition and Preliminary Engineering (PE) activities.

-12-

One of the most important next steps related to the implementation of the Atlanta North

South Tunnel is working with the Atlanta Regional Commission (ARC) to incorporate the

Tunnel project in the next update to the Regional Transportation Plan (RTP). Incl

in the RTP is required to secure federal funds for projects in metropolitan areas. In light

of GDOT’s projected near term funding constraints, and the financial gap calculated as

part of this feasibility study, it is likely that federal dollars will

public subsidy requirements of this project. It is therefore essential that the

North-South Tunnel be included in the ARC’s next RTP.

Preliminary design and permitting is projected to take approximately 5 years of the 11

year project implementation period, with 6 years of construction to follow. GDOT has

never prepared environmental documentation for a project of this type and magnitude,

and there will be challenges associated with successfully securing the appropriate

environmental permits.

Finally, construction of the Atlanta North

number of ways. Roadway tunneling at this scale would be unique for Georgia, and

GDOT must carefully consider

GDOT must decide whether to develop the Atlanta North

procure a pre-development agreement while the project is scoped and optimized. It is

critical to establish a preferred delivery method early in the pro

leverage limited resources.

gather private sector input regarding PDA and competitive hard bid procurement

strategies, and perhaps issue a request for information in order

decision on how to move forward.


One of the most important next steps related to the implementation of the Atlanta North


Tunnel project in the next update to the Regional Transportation Plan (RTP). Incl



part of this feasibility study, it is likely that federal dollars will be required to meet the

public subsidy requirements of this project. It is therefore essential that the

South Tunnel be included in the ARC’s next RTP.


ar project implementation period, with 6 years of construction to follow. GDOT has



Finally, construction of the Atlanta North-South Tunnel would be ground-


GDOT must carefully consider alternative arrangements for construction. Specifically,

GDOT must decide whether to develop the Atlanta North-South Tunnel internally or to

development agreement while the project is scoped and optimized. It is

critical to establish a preferred delivery method early in the process in order to efficiently

leverage limited resources. It is recommended that GDOT stage an industry forum to


strategies, and perhaps issue a request for information in order to assist in making a

decision on how to move forward.


One of the most important next steps related to the implementation of the Atlanta North-


Tunnel project in the next update to the Regional Transportation Plan (RTP). Inclusion



be required to meet the

public subsidy requirements of this project. It is therefore essential that the Atlanta


ar project implementation period, with 6 years of construction to follow. GDOT has



-breaking in a


ion. Specifically,

South Tunnel internally or to

development agreement while the project is scoped and optimized. It is

cess in order to efficiently

It is recommended that GDOT stage an industry forum to


to assist in making a

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