Stop the I-526 Extension



I-526 or the “Mark Clark Expressway” is an interstate in Charleston County that runs from West Ashley to Mount Pleasant. Charleston County is proposing to extend the highway from the current terminus at Savannah Highway onto Johns Island and over to James Island to connect to the James Island Connector. 

This project would displace homes and businesses, destroy over 30 acres of saltwater and freshwater wetlands, impact over 30 acres of James Island County Park, and escalate suburban sprawl on rural Johns Island. It would also cost Charleston County taxpayers $1.9 BILLION. 

Most importantly, it would not alleviate traffic congestion. Since this project weas initially conceived in the 1960s, we have learned that highway projects like this do not alleviate traffic congestion, they lead to more development that ultimately makes traffic even worse. That’s why every single community along the existing I-526 Corridor experiences intense traffic congestion.  

It’s time for Charleston County to walk away from the outdated, overpriced, and environmentally destructive I-526 Extension project and focus on realistic, responsible projects to alleviate traffic on Johns Island. 



In October 2023, the South Carolina Transportation Infrastructure Bank (SCTIB) voted to release $75 million dollars for additional preliminary planning for the I-526 Extension. This was not unexpected. The SCTIB reached an agreement in 2019 to provide $420 million dollars of funding for the project. This vote was simply the next step in the process to release the next round of funding. The SCTIB made clear they do not plan to increase their overall contribution to the project. 

What was surprising was the South Carolina Department of Transportation’s (SCDOT) satisfaction with Charleston County’s vague suggestion regarding how they will cover their portion of the project—an astounding $1.9 BILLION. SCDOT previously stated they needed a “reasonable and realistic” funding plan from Charleston County before they would proceed any further on the project. 

Charleston County shared that they hope to propose a ballot measure in 2024, which will ask taxpayers across Charleston County to pay a sales tax for 25 years, nearly half of which would go toward the I-526 Extension, a roughly 9.5-mile stretch of slow-moving parkway that would only be used by a small fraction of Charleston County. That’s not reasonable or realistic. It’s not even really a plan. It’s difficult to believe that Charleston County taxpayers will vote to direct $1.9 BILLION of funding to build 9.5 miles of roadway that will only increase suburban sprawl on Johns Island, leading to more cars on rural roads, and even worse traffic congestion. 

Every community that adjoins the existing portion of I-526 is overwhelmed by congestion. That’s because new highways don’t alleviate congestion. They have been proven to create more traffic in the long run. Are Charleston County residents really going to vote to pay $1.9 billion to build 9.5 miles of road that will ultimately make traffic worse? We hope not. 

Fortunately, there is still an opportunity to pump the brakes on this latest round of funding. The $75 million installment must still be approved by the Joint Bond Review Committee, a group of legislators from the South Carolina General Assembly who review state spending on permanent improvement projects. This committee has a long history of making sound and responsible financial decisions. We hope that will continue when they review this request and see that Charleston County still does not have a reasonable and realistic plan to cover their share of the I-526 Extension project.  

Current members of the JBRC are: 

  • Senator Harvey Peeler 
  • Senator Thomas Alexander 
  • Senator Nikki Setzler 
  • Senator Katrina Frye Shealy 
  • Senator Ronnie Cromer 
  • Representative Bruce Bannister 
  • Representative Gilda Cobb-Hunter 
  • Representative Leon Stavrinakis 
  • Representative Heather Ammons Crawford 
  • Representative Bill Herbkersman 

 It’s clear that the Charleston region needs to address congestion, especially in parts of West Ashley and Johns Island. Projects like the flyover at Main Road and Savannah Highway, as well as the Northern & Southern Pitchforks on Maybank Highway, will improve connectivity and reduce congestion at a much more reasonable cost and without opening the floodgates on rural Johns Island to suburban sprawl that will irreversibly transform the culture and character of one of the last remaining rural sea islands in the region. 



Additional background information can be found here.

Staff Contact

Robby Maynor · [email protected] · 843.810.2544

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