History of the Project
1970s
Since the early 1970’s, the original plan for the Mark Clark Expressway included a connection between West Ashley, Johns Island, and James Island.
1995
A Draft Supplemental Environmental Impact Statement (DEIS) was prepared for the remaining unbuilt 7-mile segment of I-526, connecting Savannah Highway in West Ashley to the James Island Connector on James Island. This document was not finalized.
2004
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 the 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.
2010
In 2010, the Draft Environmental Impact Statement (DEIS) for the Mark Clark Extension project was signed on July 26, 2010. The DEIS identified Alternative G as SCDOT’s Recommended Preferred Alternative for the project. Alternative G is a proposed 7.9-mile-long parkway, with an additional 1.6 miles of connector roads on Johns Island, for a total length of 9.5 miles, which includes 4.5 miles of structure and two crossings of the Atlantic Intracoastal Waterway. A multi-use path for bicycle and pedestrian use is included along the entire length of the roadway.
Now (2019 -2022)
In early 2019, funding sources were identified, and the completion of the Mark Clark Expressway, now known as the Mark Clark Extension, was again initiated. Due to the length of time that transpired since the signing of the DEIS, FHWA determined that a Supplemental Draft Environmental Impact Statement (SEIS) is required to move the project forward.
Since the 1970s, this project has held several variations of the same name as the project has progressed — from I-526 to Mark Clark Expressway to Mark Clark Extension.