Mark Clark Expressway - I-526

Project Updates

Project Status Report - Summer 2011

Upon the signing and release of the Draft Environmental Impact Statement (DEIS) in August 2010, the project team held five (5) public hearings to announce the Recommended Preferred Alternative and collect input on the project from the public and stakeholders. During the subsequent public comment period 2,170 comments were received from 1,657 individuals.

Since then, Charleston County has been working with SCDOT, FHWA, and other project stakeholders as they carefully consider the most appropriate path forward for the Mark Clark Expressway project. Once a decision on the path forward has been identified, the project team will respond to all public hearing comments and provide further updates to the community.

Thank you for your interest and participation in the project.


The DEIS has been signed

As of Monday, July 26, 2010, the South Carolina Department of Transportation (SCDOT) and Federal Highway Administration (FHWA) have signed the Draft Environmental Impact Statement (DEIS) for the Proposed Extension of the Mark Clark Expressway. SCDOT and Charleston County will hold a media release to announce SCDOT’s Recommended Preferred Alternative on Wednesday July, 28, 2010 at 10:00 in Charleston County Council Chambers.

Mark Clark Expressway Project Update Newsletters will be mailed to residents this week, also announcing the Recommended Preferred Alternative and that Public Hearings have been scheduled for August 31 and September 2 at Burke High School.

Check back for more project updates and information as it becomes available.


The last series of public meetings for the proposed Mark Clark Expressway project was held in April and May of 2009. SCDOT had initially planned to announce the Recommended Preferred Alternative by the end of 2009. Although the project has been steadily moving forward with environmental studies since that time, the project team would like to keep you informed of the progress that has been made since our last update.

Since the last series of public meetings and the Summer 2009 newsletter, the Mark Clark Expressway study team has been busy evaluating the reasonable alternatives that were presented to the public for the development of the Draft Environmental Impact Statement (DEIS). Through the development of the DEIS, alternatives have been refined, evaluated, and eliminated based on how well they addressed the need and purpose of the project and the potential impact they would have on the social, economic, and natural environment. The study team has also refined each of the reasonable alternatives in response to public comments and in order to minimize potential impacts, where possible. In addition, the study team has continued evaluation of the Mass Transit and Transportation Systems Management alternatives as introduced to the public at the meetings held in April and May 2009. A description and location map of each new construction reasonable alternative is provided below:

Alternative A (a revised version of former Alternative 1)
Alternative A extends from the existing interchange at Mark Clark Expressway/U.S. 17, across the Stono River, to intersect Maybank Highway on Johns Island. The alignment then traverses James Island south of James Island County Park to end at the existing James Island Connector/Folly Road interchange. This is a fully controlled access facility.

As a result of the input from the agencies, project stakeholders and the public, various adjustments were suggested to be made to the alignments. One mile south of U.S. 17, Alternative A was shifted east of its original position after passing over South Shore Drive in the Oakland neighborhoods to avoid impacting the community dock that serves the Battery Haig subdivision.

Alternative A Map
Alternative_A.pdf (393Kb)

Alternative B (a revised version of former Alternative 8)
Alternative B extends from the existing interchange at Mark Clark Expressway/U.S. 17, across the Stono River. On Johns Island, this alignment avoids the intersection of Maybank Highway and River Road by providing an interchange on Maybank Highway west of this intersection. The alignment traverses the Stono River and James Island, south of the James Island County Park, to end at the existing James Island Connector/Folly Road interchange. This is a fully controlled access facility.

As a result of the input from the agencies, project stakeholders and the public, various adjustments were suggested to be made to the alignments. One mile south of U.S. 17, Alternative B was shifted east of its original position after passing over South Shore Drive in the Oakland neighborhoods to avoid impacting the community dock that serves the Battery Haig subdivision.

Alternative B Map
Alternative_B.pdf (393Kb)

Alternative C (a revised version of former Alternative 10)
Alternative C extends from the existing interchange at Mark Clark Expressway/U.S. 17, across the Stono River, to intersect Maybank Highway on Johns Island. It then crosses James Island, north of James Island County Park near Ferris and Cyrus Road and connects to the existing James Island Connector/Folly Road interchange. This is a fully controlled access facility.

As a result of the input from the agencies, project stakeholders and the public, various adjustments were suggested to be made to the alignments. One mile south of U.S. 17, Alternative C was shifted east of its original position after passing over South Shore Drive in the Oakland neighborhoods to avoid impacting the community dock that serves the Battery Haig subdivision.

Alternative C Map
Alternative_C.pdf (381Kb)

Alternative D (a revised version of former Alternative 11)
Alternative D extends from the existing interchange at Mark Clark Expressway/U.S. 17 to Johns Island where two spur interchanges are located. These spurs would be partial interchanges at River Road north of Maybank Highway (Spur A) and River Road south of Maybank Highway (Spur B). The alignment then traverses James Island ending at the existing James Island Connector /Folly Road interchange. This is a fully controlled access facility.

As a result of the input from the agencies, project stakeholders and the public, various adjustments were suggested to be made to the alignments. One mile south of U.S. 17, Alternative D was shifted east of its original position after passing over South Shore Drive in the Oakland neighborhoods to avoid impacting the community dock that serves the Battery Haig subdivision.

Alternative D Map
Alternative_D.pdf (384Kb)

Alternative E (a revised version of former Alternative 11A)
Alternative E extends from the existing interchange at Mark Clark Expressway/U.S. 17 to Johns Island and provides one spur interchange, Spur 11A. (This alternative is the same as Alternative 11, but Spur B has been removed.) This spur would be a partial interchange at River Road, north of Maybank Highway and would provide a connection to Maybank Highway near Sailfish Drive. The alignment then traverses James Island ending at the existing James Island Connector/Folly Road interchange. This is a fully controlled access facility.

As a result of the input from the agencies, project stakeholders and the public, various adjustments were suggested to be made to the alignments. One mile south of U.S. 17, Alternative E was shifted east of its original position after passing over South Shore Drive in the Oakland neighborhoods to avoid impacting the community dock that serves the Battery Haig subdivision.

Alternative E Map
Alternative_E.pdf (383Kb)

Alternative F (a revised version of former Alternative 36)
Alternative F extends from U.S. 17 across the Stono River to Johns Island but it is proposed as a four-lane parkway with low speeds. On Johns Island, this alternative provides two connector roads. These access points would be located at River Road north of Maybank Highway and River Road south of Maybank Highway. On James Island, the parkway would utilize Central Park Road, which would be widened to four lanes with a raised median to the James Island Connector. Access to the parkway would be provided at intersections with Maybank Highway, Folly Road, and other future connections.

As a result of the input from the agencies, project stakeholders and the public, various adjustments were suggested to be made to the alignments. One mile south of U.S. 17, Alternative F was shifted east of its original position after passing over South Shore Drive in the Oakland neighborhoods to avoid impacting the community dock that serves the Battery Haig subdivision. Additionally, Alternative F was shifted north of its original position on James Island, west of Riverland Drive to avoid impacting Murray-LaSaine Elementary School, which is eligible for the National Register of Historic Places.

Alternative F Map
Alternative_F.pdf (381Kb)

Alternative G (a hybrid version of former alternatives 11 and 36)
Alternative G is a new hybrid alternative that was added to the range of reasonable alternatives in response to public comments made at the series of public meetings held in April and May 2009. Public comments showed support for the parkway design and the inclusion of bicycle and pedestrian facilities; but comments also expressed concerns about the potential impacts along Central Park Road associated with Alternative 36. In response to these comments, the study team looked at the possibility of alternate routes for a parkway on James Island. The study team merged the alignment of Alternative D (formerly Alternative 11) and the parkway design of Alternative F (formerly Alternative 36) into a hybrid alternative, Alternative G.

Alternative G 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 and River Road south of Maybank Highway. On James Island, the parkway would pass through the northern edge of the James Island County Park. After passing Riverland Drive, Alternative G 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. Alternative G provides access to Central Park Road via Riley Road and Up on the Hill Road. This alternative provides a multi-use path to accommodate bicycle and pedestrians.

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. Alternative G would provide connections to existing streets on James Island and would include a multi-use path along one side for its entire length to accommodate bikes and pedestrians.

Alternative G Map
Alternative_G.pdf (379Kb)

Alternative G Traffic Map
Alternative_G.pdf (4.1Mb)


Currently, SCDOT is in the process of finalizing the DEIS document and submitting it for review. The completed DEIS will provide a summary of the entire project development process, including public involvement, the evaluation of the impacts associated with each of the reasonable alternatives, and SCDOT’s Recommended Preferred Alternative.

The DEIS will be released once the document is finalized and signed by the Federal Highway Administration (FHWA) and SCDOT. Following the release of the DEIS, two public hearings will be held to provide the public with another opportunity to review the project and provide comments. The public hearing will include an informal, open-house format session, similar to past meetings. This session will provide displays with project information for the public to review and ask questions of project team members. A formal session will also take place with a presentation on the project and public comment period. Public hearing dates and locations will be announced on this website and throughout the community. These two public hearings will follow identical format and will present identical content, allowing the choice of days to attend. The public is encouraged to attend either of these two hearings. It is anticipated that the DEIS will be finalized and released to the public in Summer 2010.

Following compilation of the public hearing transcript and comments made by the public and resource and regulatory agencies on the DEIS, SCDOT will begin putting together the Final Environmental Impact Statement (FEIS).



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