This is the much debated and postponed extension of the 526 interstate.

SOUTH CAROLINA – STONO RIVER – CHARLESTON: Special Bridge Notice
The Coast Guard has published Public Notice 03-24 after having received a bridge permit application from South Carolina Department of
Transportation. The applicant is requesting approval of the location and plans for the Mark Clark Extension Bridge across the Stono River, Charleston,
Charleston County, SC. Public Notice 03-24 outlines the proposed bridge project and solicits comments on proposed navigation clearances, placement
of a bridge protective system and other navigational safety issues. The public notice is available at: https://www.navcen.uscg.gov/public-notices-forbridges-active-by-district?district=7&subdistrict=n.