Mark Clark Expressway - I-526

Mark Clark Expressway Frequently Asked Questions

Will traffic issues and safety issues associated with Johns Island and James Island be addressed in a comprehensive way?

How is the city going to address traffic on Johns Island roads (Bohicket, Main, Maybank and River Roads)?

Will the Mark Clark Extension provide a long-term solution or just move congestion around?

Will the “The New Way To Work” alternative be considered in the EIS?

Is there a map available that shows the projected path of the extended Mark Clark Expressway alignment?

What is the predicted path the new road will take?

When and where is the next Mark Clark Expressway Public Meeting?

How will the new road impact neighborhoods in its path?

Is there any additional information available? Where can I get more information about the project?

Are there plans to extend a four lane expressway from SC 30 across James and Johns Island, perhaps following River Road to Bohicket Creek Road (Betsy Kerrison)?

How is this project being funded?

How do I add my name to the email information distribution list?

What is the status of consultation under Section 106 of the NHPA?

How can I comment on the project?


Will traffic issues and safety issues associated with Johns Island and James Island be addressed in a comprehensive way?

Yes; As part of the Environmental Impact Statement (EIS), a comprehensive traffic analysis will be conducted using the BCDCOG travel demand model as the basis. This model will be updated using the most recently updated land use plans, including the Johns Island Plan by the City of Charleston and the recently updated Comprehensive Plan for Charleston County. All recently completed transportation improvement projects in this study will be incorporated as well. This includes work conducted within the City of Charleston, Town of James Island and Charleston County. This traffic analysis will be both a regional traffic analysis as well as a detailed traffic engineering exercise at and near proposed interchanges.

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How is the city going to address traffic on Johns Island roads (Bohicket, Main, Maybank and River Roads)?

For projects within the City of Charleston, please contact the City office of Traffic & Transportation at (843) 720-1993. For traffic issues outside of the City limits and projects being conducted by Charleston County, please refer to the website for Charleston County RoadWise. All adopted land use plans and committed transportation projects will be incorporated into the traffic analysis for the Mark Clark Expressway EIS.

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Will the Mark Clark Extension provide a long-term solution or just move congestion around?

It is the goal of all transportation projects to improve mobility. In the case of the proposed I-526, the level of improvement provided by the proposed facility will be evaluated as part of the EIS. The traffic analysis will be conducted to a forecast year of 2035 for the evaluation of the performance of the project.

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Will the “The New Way To Work” alternative be considered in the EIS?

The National Environmental Policy Act (NEPA) requires alternatives to be considered in the EIS. The alternatives to be evaluated in the Mark Clark Expressway EIS are expected to include: (1) No-build; (2) Transportation System Management (TSM); (3) alternative modes of transportation and (4) build alternatives including upgrades to existing roads and one or more new location alternatives. The alternatives to be investigated in the EIS will be developed with input from agencies and the public during the initial coordination/scoping period and subsequent agency and public involvement opportunities.

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Is there a map available that shows the projected path of the extended Mark Clark Expressway alignment?

As the project has progressed, maps of the potential alignments for the extended Mark Clark Expressway have been posted to the project website. The SCDOT Recommended Preferred Alternative was identified in the DEIS as Alternative G. Please see the Maps and Photos Page for a map of this alignment.

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What is the predicted path the new road will take?

SCDOT’s Recommended Preferred Alternative extends from U.S. 17 across the Stono River to Johns Island as a four-lane parkway facility with low speeds (i.e. 35 to 45 mph). This alternative provides two connector roads onto Johns Island. These connector roads would tie into River Road north of Maybank Highway (between Rushland Landing Road and Penny Lane) and River Road south of Maybank Highway (in the vicinity of Cane Slash Road) and would include improvements to the Maybank Highway/River Road intersection. On James Island, the parkway would pass through the northern edge of the James Island County Park. After intersecting Riverland Drive, the parkway continues northeast, south of the Regatta Apartments, Carmike James Island Cinema and the U.S. Post Office, tying into the existing James Island Connector/Folly Road interchange. Access is provided to Central Park Road via Riley Road and Up on the Hill Road.

Within the James Island County Park, a minor shift in the alignment moved the parkway closer to the northern boundary of the park to minimize disruptions to park facilities. SCDOT’s Recommended Preferred Alternative includes a multi-use path along one side of the parkway for its entire length to accommodate bikes and pedestrians. The multi-use path associated with SCDOT’s Recommended Preferred Alternative provides additional connectivity to the West Ashley Greenway and the James Island County Park.

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When and where is the next Mark Clark Expressway Public Meeting?

Following the release of the DEIS, five public hearings were held in Summer 2010 to provide the public with opportunities to comment on the DEIS and the SCDOT Recommended Preferred Alternative. As this time, no other public meetings are scheduled to be held for this project.

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How will the new road impact neighborhoods in its path?

SCDOT has released the DEIS, a process that which includes the evaluation of alternatives and comparison of impacts on both the natural and human environment. All impacts to both the natural and human environment have been and will continue to be minimized to the extent possible. The results showing both the benefits and impacts to nearby neighborhoods and communities is included in the DEIS. Specific community and neighborhood impacts have been identified at this time and can be found in Chapter 5 (Part 6, Part 7, Part 8 and Part 9) of the DEIS. A detailed Community Impact Assessment (Appendix N) was conducted in relation to the reasonable alternatives.

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Is there any additional information available? Where can I get more information about the project?

The DEIS is online and available here. SCDOT will continue to update the website with information about the project as it continues. Public information meetings throughout the project have been held within or adjacent to the project area to present new information as it was identified and provided the public opportunity to comment on the project. Newsletters haven been distributed through email or mail and will be sent to those who have asked be on the project distribution list. Newsletter content is available on the project website.

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Are there plans to extend a four lane expressway from SC 30 across James and Johns Island, perhaps following River Road to Bohicket Creek Road (Betsy Kerrison)?

Please see the Charleston County Roadwise website for more information about this project.

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How is this project being funded?

In November 2004, the voters of Charleston County approved a half-cent sales tax for transportation, public transportation and greenbelt projects in the county. To complete the plan for Mark Clark Expressway, Charleston County officials used these sales tax transportation projects as a local match to apply for funding from the South Carolina Transportation Infrastructure Bank (SIB) in 2006. Upon review of the application and the availability of matching funds, the SIB committed to fund the project.

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How do I add my name to the email information distribution list?

To add your contact information to the email distribution list, please send us a comment via the contact form. Now all you need to do is click the check box labeled “please add me to the distribution list” when submitting a comment.

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What is the status of consultation under Section 106 of the NHPA?

The Section 106 review and compliance for the Mark Clark Expressway Extension begins with SCDOT coordinating with the South Carolina State Historic Preservation Office (SC SHPO) and conducting public meetings to identify historic resources within the potential area of effect for this project. In addition to consultation with SHPO, SCDOT will coordinate with all local, state, tribal, and federal agencies, and the public to identify consulting parties throughout the length of the environmental review process. The coordination and involvement initiatives for this project began with a public scoping meeting held April 10, 2008 and an agency scoping meeting held April 29, 2008. Coordination initiatives continued with public meetings held in November/December 2008 and April/May 2009. Additionally, coordination meetings have been held with SHPO and consulting parties to assess historic resources and identify potential impacts by the project.

The results of the historic resources survey and details concerning coordination meetings will be included in the Draft Environmental Impact Statement which is scheduled to be released in Spring 2010.

For further information regarding agency coordination and public involvement, please click here to view the Draft Agency Coordination and Public Involvement Plan.

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How can I comment on the project?

  • Informal public information meetings will be held periodically throughout the length of the project. These meetings will be advertised in newspapers and mail notifications. After each meeting there will be a 15-day comment period on the project.

  • Formal Public Hearings will be held upon completion of the Draft EIS and Final EIS. There will be a 45-day comment period, at the time of the public hearings, during which the public may submit comments to SCDOT and FHWA concerning the Draft EIS.

  • Use the contact form to submit comments about the project.

Contact Information:
Jae H. Mattox, III, P.E.
SCDOT Project Manager
P.O. Box 191
Columbia, SC 29202-0191

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