Station 2

English  -  Español

Alternatives Evaluation Process

Alternatives Analysis Video

If you’re having problems viewing the video, please open the Alternative Analysis video in a new tab ⬈

 

Alternatives Evaluation Process

 
 

The project team has performed traffic analysis, environmental studies, and preliminary design to identify and analyze the transportation solutions which meet the purpose and need of this corridor. The preliminary range of alternatives was evaluated to determine which of the alternatives would meet the purpose and need of the project. While other alternatives, such as increased transit and flex hours (known as Travel Demand Management) did not show enough of a traffic reduction potential to be standalone solutions, many were determined to be cost-effective and have some positive impact. To begin alleviating some of the growing congestion today, we have funded and begun implementing many of these solutions.

The preliminary alternatives were then evaluated to determine if they were both practicable and feasible. The alternatives that met each of these criteria, along with the no-build alternative, were identified as the Proposed Reasonable Alternatives and were presented to you last Fall. Based on your feedback last fall, we also developed a few new alternatives at North Rhett Avenue - for a total of 5 Reasonable Alternatives.

All the Reasonable Alternatives were evaluated again to arrive at today’s Recommended Preferred Alternative. This detailed evaluation focused on each alternative's traffic performance and potential impacts to communities and the natural environment.

View Detailed Process I-526 Corridor Analysis Planning Study

The following are the solutions that we have begun implementing with partners to begin alleviating traffic congestion today.

  • Signal Timing Improvements at 6 interchanges
  • Lowcountry GO Program and Mobile App
  • Stagger Start/End Time at Major Employers
  • Compressed Work Week
  • Telecommuting
  • Flex Hours

Preliminary Range of Alternatives (2016)

  • The preliminary range of alternatives were presented to the public in a Public Meeting held online in November 2016.

Evaluation on Purpose & Need and Traffic Analysis (2016 - 2019)

  • The preliminary range of alternatives was evaluated for their ability to meet the purpose and need of the project and based on a traffic analysis. Based on this analysis, alternatives were eliminated.

Proposed Reasonable Alternatives (2019)

  • The proposed reasonable alternatives were presented to the public at the Public Information Meeting held on November 21, 2019.
  • Following the comments received from the public and agencies during the Public Information Meeting, new Reasonable Alternatives were developed for the North Rhett/Virginia Avenue Interchange. These included North Rhett/Virginia Avenue Alternative 2A, Alternative 5, and Alternative 6.

Detailed Impact Evaluation (2020)

  • Following the detailed impact evaluation, Alternatives were Eliminated to arrive at the Recommended Preferred Alternative.

Recommended Preferred Alternative (2020)

  • The recommended preferred alternative is being presented at the Public Hearing this year (2020). The recommended preferred alternative consists of:

    • Alternative 1 at Paul Cantrell Boulevard to International
    • Alternative 2 from International Boulevard to Rivers Avenue
    • Alternative 2A from Rivers Avenue to Virginia Avenue
 

Preliminary Screening of Range of Alternatives - Table 1

The following table outlines the evaluation of the preliminary range of alternatives based on the alternative’s ability to satisfy the purpose and need.

Preliminary Screening of Range of Alternatives - Table 1
No Build Improvement to Existing Local Facilities New Location Managed Lanes* TSD/TDM* Mass Transit* Existing Corridor Improvements
East Montague Avenue Remount Rd US 78 to Virginia Ave Ashley Phosphate Rd to Virginia Ave Bees Ferry Rd to Dorchester Rd
Does the alternative satisfy the project's Purpose and Need? - No No No No No No No No Yes
Was it carried forward as a Preliminary Alternative? Yes No No No No No No No No Yes
 

Preliminary Screening of Range of Alternatives - Table 2

The table below outlines the evaluation of the preliminary range of alternatives based on the traffic analysis.

Preliminary Screening of Range of Alternatives - Table 2
No Build Mainline I-526 at Paul Cantrell Blvd Paul Cantrell Blvd at Magwood Dr I-26/I-526 System I-526 at Rivers Ave I-526 at N Rhett/ Virginia Ave
6-lane 8-lane 1 2 3 4 5 1 2 3 4 5 6 7 1 2 3 4 1 2 1 2 3 4
Acceptable LOS No No Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
Compatible with Adjacent Interchange - - - No Yes No Yes Yes No Yes No No Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No
Geometric Deficiencies Resolved No - - Yes Yes Yes Yes Yes - - - - - - - Yes Yes Yes Yes No No Yes Yes Yes Yes
Flexibility with Don Holt Bridge Replacement Yes Yes Yes - - - - - - - - - - - - - - - - - - Yes Yes Yes Yes
Constructability - Yes Yes Yes No Yes No Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes N o Yes
Carried Forward as a Reasonable Alternative Yes No Yes No No No No Yes No No No No Yes No No Yes Yes No No Yes Yes Yes Yes No No
 

Detailed Impact Evaluation:
Paul Cantrell Boulevard to International Boulevard

This table identifies the criteria and results of the detailed impact evaluation for the segment from Paul Cantrell Boulevard to International Boulevard.

Detailed Impact Evaluation: Paul Cantrell Boulevard to International Boulevard
No Build Paul Cantrell Blvd to International Blvd*
What is the Weighted Volume/Capacity Ratio? Paul Cantrell to Leeds: 1.74
Leeds to Dorchester: 2.50
Dorchester to Montague: 2.90
Montague to International: 3.11		 Paul Cantrell to Leeds: 0.72
Leeds to Dorchester: 0.75
Dorchester to Montague: 0.72
Montague to International: 0.67
What would be the Mainline Level of Service in 2050? F Paul Cantrell to Leeds: D
Leeds to Dorchester: D
Dorchester to Montague: C
Montague to International: C
Number of Freshwater Wetland Impacts 0 acres 19.3 acres
Number of Stream Impacts 0 feet 327.0 feet
Number of Critical Area Impacts 0 acres 19.6 acres
Number of Relocations Proposed 0 10
Environmental Justice Impacts Present No Yes
Are Cultural Resources present? No No
Are Section 4f/6f Impacts present? No No
Cost of Utility Impacts $0 $12.9 Million
Cost of Construction $0 $108 Million
 

Detailed Impact Evaluation:
International Boulevard to Rivers Avenue (including I-526 at I-26)

This table identifies the criteria and results of the detailed impact evaluation for the segment from International Boulevard to Rivers Avenue (including I-526 at 1-26.)

Detailed Impact Evaluation: International Boulevard to Rivers Avenue (including I-526 at I-26)
No Build Alternative 1 Alternative 2* Alternative 1A Alternative 2A
What is the Weighted Volume/Capacity Ratio? 1.09 0.74 0.71 0.77 0.74
What would be the Mainline
Level of Service in 2050?		 F C C C C
Number of Freshwater Wetland Impacts 0 acres 28.5 acres 28.5 acres 28.5 acres 28.5 acres
Number of Stream Impacts 0 feet 13,327.1 feet 13,271.1 feet 13,327.1 feet 13,327.1 feet
Number of Critical Area Impacts 0 acres 0 acres 0 acres 0 acres 0 acres
Number of Relocations Proposed 0 103 101 124 124
Environmental Justice Impacts Present No Yes Yes Yes Yes
Are Cultural Resources present? No No No No No
Are Section 4f/6f Impacts present? No Yes Yes Yes Yes
Cost of Utility Impacts $0 $31 Million $31 Million $31 Million $31 Million
Cost of Construction $0 $950 Million $979 Million $1,068 Million $1,066 Million
 

Detailed Impact Evaluation: Rivers Avenue to Virginia Avenue

This table identifies the criteria and results of the detailed impact evaluation for the segment from Rivers Avenue to Virginia Avenue.

Detailed Impact Evaluation: Rivers Avenue to Virginia Avenue
No Build Alternative 1 Alternative 2 Alternative 5 Alternative 6 Alternative 2A*
What is the Weighted Volume/Capacity Ratio? 1.14 1.00 0.99 0.86 0.91 0.91
What would be the Mainline Level of Service in 2050? F Rivers to N Rhett: C
N Rhett to Virginia: D		 Rivers to N Rhett: C
N Rhett to Virginia: D		 Rivers to N Rhett: C
N Rhett to Virginia: D		 Rivers to N Rhett: C
N Rhett to Virginia: D		 Rivers to N Rhett: C
N Rhett to Virginia: D
Number of Freshwater Wetland Impacts 0 acres 54.5 acres 51.3 acres 57.3 acres 50.8 acres 49.9 acres
Number of Stream Impacts 0 feet 5,159.6 feet 5,169.1 feet 5,197.4 feet 5,205.9 feet 4,977.6 feet
Number of Critical Area Impacts 0 acres 2.3 acres 2.3 acres 2.8 acres 2.7 acres 2.4 acres
Number of Relocations Proposed 0 4 4 4 4 2
Environmental Justice Impacts Present No Yes Yes Yes Yes Yes
Are Cultural Resources present? No No No No No No
Are Section 4f/6f Impacts present? No No No No No No
Cost of Utility Impacts $0 $4.5 Million $4.5 Million $5.6 Million $5.6 Million $5.6 Million
Cost of Construction $0 $336 Million $338 Million $473 Million $461 Million $341 Million
 

Recommended Preferred Alternative: All Segments Combined

This table identifies compares the No Build alternative to the Recommended Preferred Alternative, combining the information from all three segments into one simplified table.

Detailed Impact Evaluation: All Segments Combined
No Build Recommended Preferred Alternative*
What is the Weighted Volume/Capacity Ratio? Greater than 1.0 Less than 1.0
What would be the Mainline
Level of Service in 2050?		 F Paul Cantrell Blvd to Leeds Ave: D
Leeds Ave to Dorchester Rd: D
Dorchester Rd to Montague Ave: C
Montague Ave to International Blvd: C
International Blvd to I-26
I-26 to Rivers Ave: C
Rivers Ave to North Rhett Blvd: C
North Rhett Ave to Virginia Ave: D
East of Virginia Ave: C
Number of Freshwater Wetland Impacts 0 acres 97.7 acres
Number of Stream Impacts 0 feet 18,631.7 feet
Number of Critical Area Impacts 0 acres 22 acres
Number of Relocations Proposed 0 113
Number of Environmental Justice Relocations 0 92
Are Cultural Resources present? No Yes
Are Section 4f/6f Impacts present? No Yes
Cost of Utility Impacts $0 $53.5 Million
Cost of Construction $0 $1.428 Billion