Interstate 526 South Carolina

Westbound Interstate 526 (Mark Clark Expressway) crosses the Cooper River via the Don N. Holt Bridge, a steel through truss bridge opened on March 10, 1992,1 as an integral connection through into North Charleston. The main span is 800 feet long and cost $20 million to build. Photo taken 05/30/07.

Routing

Interstate 526 serves as a north-south bypass of Charleston metro to the north and west, connecting with U.S. 17 on either end (and thus offering a bypass of downtown Charleston for through traffic on U.S. 17). The highway crosses over the Cooper River on the Don Holt Bridge, a three span continuous modified Warren truss (structural steel).1 The eastern terminus is located at Business Spur I-526, which continues past U.S. 17 to South Carolina 703 (Coleman Boulevard). The western end is also at U.S. 17, and has stub ramps for the planned extension to South Carolina 30.

History

AASHTO approved the numbering of Interstate 526 initially on June 29, 1978 from I-26 southeast to U.S. 17 & 701 in Mount Pleasant. The western extension of I-526, from North Charleston to SC 7 was approved by AASHTO on October 6, 1989. The route was signed shortly thereafter, starting with the section that was formerly signed as South Carolina 31 from U.S. 17 northeast to Interstate 26. Dedicated on June 20, 1992,2 Interstate 526 was extended southeast to rejoin U.S. 17 north of Charleston with the completion of the Don N. Holt Bridge over the Cooper River. The freeway directly transitions onto Business Spur I-526 in Mt. Pleasant, which was also signed in 1992.

Future Aspirations

Interstate 526 will to continue from its current western terminus by looping to the south toward Folly Beach then east onto James Island and connecting to the South Carolina 30 Freeway. South Carolina 30 represents the southeastern leg of Interstate 526. Debated and delayed for two decades, the South Carolina Department of Transportation moved forward on a contract to complete the remaining portion of I-526 on December 5, 2013. This measure went forward after the Charleston County Council voted to proceed with the contract in December 2013. Although not yet fully funded, the initial contract is estimated at $558-million.3 When work breaks ground, which optimistically will be 18 months from the SCDOT approval in December 2013, I-526 could be completed by 2020.4

South Carolina 31 History

The first segment of what is now Interstate 526 was designated as South Carolina 31. The 1983 Rand McNally Road Atlas displays the first segment of the eventual Interstate 526 between U.S. 17 and South Carolina 642 (Dorchester Road) as South Carolina 31. The Mark Clark Expressway was named in 1976 after General Clark, a World War II hero and former president of The Citadel, Charleston's military college.5

South Carolina 31 was recycled with the December 17, 2002 opening of the Carolina Bays Parkway between U.S. 501 and South Carolina 9, north the Grand Strand. That parkway, extended west to South Carolina 544 on December 15, 2004, is a part of future Interstates 73 and 74.

Highway Guides

Western Terminus - U.S. 17 - western Charleston, South Carolina
Perspective from Interstate 526 west
Westbound on Interstate 526, 0.75 miles before the current conclusion at U.S. 17 and South Carolina 7. The newer sign is reflective, while the original button copy guide sign was in place in 2003. Photos taken by 05/30/07 and by Chris Patriarca (06/08/03).
End freeway one half mile caution sign. This is the second Interstate terminus in South Carolina to feature this type of sign assembly. The other is located at the northern terminus of Interstate 185 at Greenville. Photo taken 05/30/07.
The westbound lanes of Interstate 526 end at a traffic signal, which not how the eastbound lanes begin. Whereas eastbound lanes exit on a flyover ramp from U.S. 17 north, the westbound lanes connect to South Carolina 7/Sam Rittenberg Parkway at the first traffic signal, then connect to U.S. 17 itself at a second traffic signal. Once Interstate 526 is extended to connect with South Carolina 30, this situation will be corrected. Photo taken 05/30/07.
A temporary all traffic must exit sign is posted at the U.S. 17/South Carolina 7 westbound ramp. A freeway stub exists to the west for the planned extension southward to James Island. Photo taken 05/30/07.
This is the first advance sign for the temporary final exit at South Carolina 7/Sam Rittenberg Parkway at the first traffic signal. The second traffic signal for U.S. 17 can be seen in the distance. Photo taken 05/30/07.
The end of Interstate 526 resides at this intersection with South Carolina 7. An identical set of signs is posted on either side of the exit ramp as shown in these two photos. The Interstate 526 ramp continues as a service road to U.S. 17 for Charleston based traffic interests of northbound. The overpass to the left is part of the future Interstate 526 extension. Photos taken by 05/30/07 and by Chris Patriarca (06/08/03).
Looking past the South Carolina 7/Sam Rittenberg Parkway traffic signal, a trailblazer for U.S. 17 is posted on the right side of the road. Photo taken 05/30/07.
Westbound Interstate 526 ends at this traffic signal with U.S. 17. Use U.S. 17 north to downtown Charleston and south to Savannah, Georgia. Photo taken 05/30/07.
As seen in this photo, it is possible to use the middle lane to turn north onto U.S. 17 and then immediately get back onto Interstate 526 east to North Charleston. Photo taken 05/30/07.
Perspective from U.S. 17 north
Eastbound on U.S. 17 north as it enters the Charleston metropolitan area. Featured here is a Port Terminals guide sign for commercial truck traffic to the S.C. Ports Authority. The facility is located off of Interstate 526 Exit 20 at North Charleston. Photo taken by Chris Patriarca (06/11/03).
Approaching the Interstate 526 western terminus with another reminder of the freeway's connection to the S.C. Ports Authority. Photo taken by Chris Patriarca (06/11/03).
U.S. 17 eastbound as it nears the split with South Carolina 7 north/Sam Rittenberg Boulevard and the eastbound beginning of Interstate 526. Photo taken by Chris Patriarca (06/11/03).
U.S. 17 sees this set of overheads in anticipation of the Interstate 526 and South Carolina 7 terminus complex. Interstate 526 and South Carolina 7 represent two of the four Ashley River crossings of the Charleston metropolitan area. Photo taken by Chris Patriarca (06/08/03).
U.S. 17 northbound expands to five lanes in the vicinity of the Interstate 526 western terminus. South Carolina 7 northbound departs U.S. 17 at this point and crosses underneath the Interstate 526 eastbound beginning to the left. Photo taken by Chris Patriarca (06/08/03).
Interstate 526 eastbound shield directing U.S. 17 southbound traffic onto the cloverleaf ramp that represents the Interstate 526 eastbound beginning. The overpass above carries Interstate 526 eastbound only at the present time. An overhead sign for the ramp connection was added between 2003 and 2007. Photos taken by 05/30/07 and by Chris Patriarca (06/08/03).
Perspective from U.S. 17 south
East Interstate 526 shield assembly, posted on U.S. 17 southbound as it nears the terminus interchange. In the background is the South Carolina 7 shield and an Interstate 26 trailblazer pointing toward Interstate 526 east. These signs were replaced in 2006. Photos taken by Chris Patriarca (06/08/03) and on 11/12/06.
The eastbound beginning of Interstate 526 from U.S. 17 southbound departs at this location. U.S. 17 otherwise continues to the west to Johns Island, Interstate 95, and ultimately Savannah, Georgia. The highway continues as a multi-lane divided highway for another 26 miles to Jacksonboro. These signs were also replaced by 2006. Photos taken by Chris Patriarca (06/08/03) and on 11/12/06.
Southbound U.S. 17 meets Interstate 526 east at this on-ramp. This overhead sign was added between 2003 and 2006. Continue south on U.S. 17 to downtown Charleston; use Interstate 526 to bypass the city center. Photo taken 11/12/06.
Perspective from Interstate 526 east
This is the eastbound beginning of Interstate 526. Traffic from U.S. 17 north merges with oncoming traffic of U.S. 17 south at this point. The on-ramp in the distance allows South Carolina 7/Sam Rittenberg Boulevard traffic access to the Interstate 526 east. The first reassurance shield (not shown) is found shortly thereafter. Photo taken by Chris Patriarca (06/08/03).
Future Western Terminus - South Carolina 30 & Lockwood Drive - Charleston, South Carolina
Perspective from South Carolina 30 north (Future Interstate 526 east)
The final mainline interchange of the South Carolina 30 freeway is the Exit 1 trumpet interchange with the southern terminus of South Carolina 61. The numbering of the South Carolina 30 interchange is representative of the planned mileage of a completed Interstate 526. Photo taken by Chris Patriarca (06/12/03).
Continuing beyond the South Carolina 61 junction, South Carolina 30 crosses the Ashley River into the central business district of Charleston. The short freeway segment splits into ramps for Lockwood Drive and Calhoun Street. Photo taken by Chris Patriarca (06/12/03).
End freeway caution sign posted as South Carolina 30 enters the city of Charleston. Although the freeway of South Carolina 30 ends here, the state route continues northward along Lockwood Drive to a terminus at U.S. 17. Photo taken by Chris Patriarca (06/12/03).
The South Carolina 30 freeway concludes at this partition for ramps to Calhoun Street east for Downtown, Lockwood Drive south to the historic Battery district, and the South Carolina 30 northbound connection via Lockwood Drive to U.S. 17. Photo taken by Chris Patriarca (06/12/03).
Descending to grade level, traffic can continue on South Carolina 30 via this cloverleaf ramp to Lockwood Drive north, or traffic can proceed straight onto Calhoun Street east. Photo taken by Chris Patriarca (06/08/03).
Perspective from Calhoun Street west
Calhoun Street draws to a close at the ramps to South Carolina 30. Traffic that does not wish to continue on the James Island freeway can depart northbound on Lockwood Drive. While northbound Lockwood is a part of South Carolina 30, the route is only shown as traveling southbound. Photo taken by Chris Patriarca (06/12/03).
Perspective from Lockwood Drive north
Lockwood Drive is a surface street that straddles the west shore of the Ashley River from the historic Battery to U.S. 17. This northbound photograph shows the highway approaching the South Carolina 30 interchange. In the background is the viaduct of South Carolina 30 as it crosses the Ashley River to South Carolina 61. Photo taken by Chris Patriarca (06/12/03).
Cloverleaf ramp of South Carolina 30 southbound as it departs from Lockwood Drive north. The short freeway segment includes four interchanges at present: the northern terminus junction here, Exit 1 with South Carolina 61, Exit 2 with Harbor View Road, and Exit 3 with South Carolina 171/Folly Road. Photo taken by Chris Patriarca (06/12/03).
Perspective from Lockwood Drive south
Lockwood Drive southbound as it passes underneath the U.S. 17 Ashley River bridge. This location represents the southbound beginning of South Carolina 30. Beyond the left-hand turn to U.S. 17 north, Lockwood Drive travels 0.25 miles to the South Carolina 30 freeway beginning. Photo taken by Chris Patriarca (06/12/03).
South Carolina 30 departs Lockwood Drive southbound at this gore point. The state route does not continue any further than the freeway that it travels upon to James Island. Therefore if Interstate 526 is completed, the South Carolina 30 designation will no longer be needed. Photo taken by Chris Patriarca (06/12/03).
Eastern Terminus - U.S. 17 - eastern Charleston, South Carolina
Perspective from Interstate 526 east
Entering the final mile of Interstate 526 eastbound and nearing the U.S. 17 junction. Exit numbers at present are only applied to Interstate 526 between Interstate 26 and Exit 24 at Daniel Island. This particular guide sign does include a blank exit tab. Photos taken by Chris Patriarca (06/09/03) and on 11/12/06.
There are two connections between Interstate 526 and U.S. 17. The first departs in this eastbound scene toward U.S. 17 north. This ramp is complimented with a return ramp to Interstate 526 west. Beyond this split is the second connection that is constituted by a partial cloverleaf interchange for U.S. 17 south. Photos taken by Chris Patriarca (06/09/03) and on 11/12/06.
Continuing beyond the U.S. 17 northbound access ramp Interstate 526 encounters the U.S. 17 southbound ramp and transition into Business Spur 526 south. The Business Spur is one of four in the state of South Carolina. Photos taken by Chris Patriarca (06/09/03) and on 11/12/06.
After crossing over U.S. 17, Interstate 526 sees this end freeway sign. Business Spur I-526 continues to the southwest along Coleman Boulevard to South Carolina 703. The divided artery allows traffic from Sullivans Island and Mount Pleasant direct access to Interstate 526. Photo taken by Chris Patriarca (06/12/03).
Now at-grade, Business Spur 526 encounters a traffic light at Bowman Road. Further southwest, the spur travels an additional mile to the merge onto South Carolina 703 west. Business Spur 526 is well signed, just as Business Spur 20 is in Florence. The other two business spurs in the Palmetto State: Business Spur 385 in Greenville and Business Spur 126 in Columbia are only sparsely signed. Photo taken by Chris Patriarca (06/12/03).
Perspective from Business Spur I-526 north
After the Bowman Road intersection, northbound Business Spur I-526 approaches its junction with U.S. 17, the major north-south coastal route between Charleston and Wilmington via Myrtle Beach. Photo taken 11/12/06.
Business Spur I-526 north meets U.S. 17 at this off-ramp. At this interchange, the business spur transitions onto Interstate 526 west. The first mainline interchange of the Charleston belt line is 1.50 miles to the north at Long Point Road and the South Carolina Ports Authority Wando Terminal. Photos taken by Chris Patriarca (06/09/03) and on 11/12/06.
Perspective from U.S. 17 north
U.S. 17 northbound nearing the Interstate 526 west/Business Spur 526 southbound junction. A junction shield is posted for the Business Spur but not the Interstate route. Photo taken by Chris Patriarca (06/12/03).
The Business Spur 526 southbound ramp departs U.S. 17 north. Known as Coleman Boulevard, the route loops into downtown Mount Pleasant (pop. 30,108) via South Carolina 703. South Carolina 703 begins at U.S. 17 just east of the Cooper River. Photo taken by Chris Patriarca (06/12/03).
Interstate 526 westbound begins as a cloverleaf ramp from U.S. 17 north. Otherwise the US highway continues two miles to the South Carolina 517 Isle of Palms Connector. That resort community, Foley's Island, and Sullivan's Island were all decimated during the category 3 landfall of Hurricane Hugo in September of 1989. Photo taken by Chris Patriarca (06/12/03).
Interstate 526 button copy gore point sign at the ramp departure from U.S. 17 north. Accompanying this sign assembly is a hurricane evacuation trailblazer. Interstate 526 will play a pivotal role when it is fully complete between Charleston, James Island, North Charleston, and Mount Pleasant for evacuation situations such as existed during Hurricane Hugo. Photo taken by Chris Patriarca (06/12/03).
The aforementioned second connection of Interstate 526 eastbound to U.S. 17 northbound indeed features return access to Interstate 526 west. This ramp is also available for U.S. 17 northbound motorists as this sign assembly suggests. Photo taken by Chris Patriarca (06/09/03).
Perspective from U.S. 17 south
A set of button copy overheads proclaims the ramp departure of the Interstate 526 westbound beginning from U.S. 17 southbound. This ramp departs independent of the Business Spur 526 partial cloverleaf interchange ahead. Photo taken by Chris Patriarca (06/09/03).
Interstate 526 westbound shield assembly at the gore point of U.S. 17 southbound to the Charleston belt line beginning. Included at the ramp beginning is an airport trailblazer. This assembly directs motorists to Charleston International Airport 14 miles to the northwest. Photo taken by Chris Patriarca (06/09/03).
Now beyond the Interstate 526 connector, U.S. 17 southbound nears Business Spur 526 south. Although the interchange is not yet visible to motorists, a junction sign for Business Spur I-526 is posted for the upcoming junction. Photo taken by Chris Patriarca (06/09/03).
The Interstate 526/Business Spur 526 mainline passes above U.S. 17. The southbound ramp of Business Spur I-526 departs U.S. 17 south; note the changes in signage between 2003 and 2006 (no more button copy). Also featured is a South Carolina 703 trailblazer for Chuck Dawley Boulevard. Central Mount Pleasant is two miles to the southwest while downtown Charleston is still four miles to the west. Photos taken by Chris Patriarca (06/09/03) and on 11/12/06.
Business Spur 526 eastbound gore point sign at the cloverleaf ramp of U.S. 17 southbound. The route should be sign posted as north-south, considering the southwest to northeast orientation. Photos taken by Chris Patriarca (06/09/03) and on 11/12/06.
Perspective from Interstate 526 west
After traffic from the U.S. 17 northbound connector merges with traffic from Business Spur 526, the first Interstate 526 westbound reassurance shield is posted. The shield was changed between 2003 and 2007 - now it features FHWA Series D font rather than FHWA Series C font. Approximately ten miles separate the U.S. 17 interchange from the Interstate 26 parent junction and city of North Charleston. Photos taken 05/30/07 and by Chris Patriarca (06/09/03).

Sources:

  1. Case Studies: Cooper River Bridge Fact Sheet - by Cornell University.
  2. "Spartanburg officials joyous over decision." Herald-Journal (Spartanburg, SC), June 21, 1992.
  3. "SCDOT Commission approves revised I-526 contract." The Post and Courier (Charleston, SC), December 5, 2013.
  4. "SCDOT Commission approves I-526 completion project." WCBD-TV2 (Charleston, SC), December 5, 2013.
  5. "STATE'S PRAISES OFTEN HIT THE ROAD S.C. HAS TRADITION OF NAMING ROADS." The State (Columbia, SC), February 12, 1996.

Page Updated December 18, 2013.