It’s Not Just A Street, It’s A SuperStreet

It’s Not Just A Street, It’s A SuperStreet

County Council green lights SCDOT plan for state’s first “superstreet”

By Charlie Morrison

Staff Writer

Charleston County Council gave the South Carolina Department of Transportation (SCDOT)’s “superstreet” project the green light. The so-called superstreet is designed to improve the accident-riddled intersection at the corner of Main Road and Savannah Highway. The design was selected from a handful of options to improve the intersection, which included road widening for additional lanes, the construction of a grade separated interchange, and “no build,” amongst others. The superstreet intersection will be South Carolina’s first, and while it was chosen primarily for safety reasons, it will also reduce red light wait times, according to the SCDOT’s Keith Riddle.

The key component of the superstreet design is it prevents drivers approaching the intersection from either direction from making a left turn or driving straight through the intersection. The design of the superstreet is such that drivers approaching the interchange from Main Road wanting to go straight through or make a left must instead make a right, then utilize dedicated U-turn lanes installed in each direction on Savannah Highway. SCDOT hired Stantec Consulting for project designs and schematics.

Grimball Road Extention Development Schematic

A North Carolina State University research project conducted from 2006-2009 showed that North Carolina’s superstreet intersections experienced a 46 percent reduction in the number of accidents at the intersection over the same time period, with a 63 percent improvement in the number of injuries and fatalities incurred there. According to Riddle, figures like those made the decision to implement a superstreet interchange at the intersection a no-brainer.

In addition the improvements to safety, the superstreet also projects to reduce wait times at the busy intersection. At peak hours, cars driving on Savannah Highway can back up to a length exceeding 2,500 feet, nearly half a mile. Projections regarding the superstreet show that number decreasing to just 500 feet in just over two decades.

“It may be the first on in South Carolina but its been used across the nation for quite a while,” says Riddle of the superstreet. “It’s a proven record we just haven’t done one yet in South Carolina. For safety, its great. These intersections have a proven track record for improving safety.

“Highway 17 is already kind of set up for it, it’s a divided, multi-lane intersection with a history of being dangerous and causing accidents,” says Riddle.

The project, being handled by the SCDOT’s Safety Office, is partially funded by the federal Highway Safety Improvement Program. The Safety Office utilizes data mining of crash statistics to determine prime candidates for infrastructure-related improvements.

According to SCDOT statistics the intersection at Main Road and Savannah Highway was home to more than 350 accidents between 2003-2011. More than 190 injuries occurred at the intersection in the same time period. Three people died as a result of their injuries in Main/Maybank crashes, and a fourth was added to that list just this past December.

Funding for the estimated $3.5 million project will come from two sources. The SCDOT has access to $2 million in federal safety monies available for the project. Charleston County Council, last Tuesday, directed County staffers to identify $1.5 million from Charleston County Half-Cent Transportation Sales Tax revenues to Council will reallocate to the project. The motion to fund the project was offered up by County Councilman Elliot Summey, seconded, and then passed unanimously by Council. Upon a staff’s presentation of how the money will be reallocated, the project will likely be fully funded.

According to Riddle, the most difficult aspect of the project is explaining it to the public, who that unless they’ve left the state, have never seen a comparable intersection.

“It’s hard to show people that its going to work and it’s different, that’s the downside, but one we get it going I think people will like it,” says Riddle. “As far as safety and reducing congestion, economic impacts and environmental impacts, there are no downsides with any of those.”

In an effort to help answer questions from the community, County Councilwoman Anna Johnson held a public meeting to discuss the roadway, where the money will be coming from and other aspects of the plan on Tuesday (after press time).

For more information on the SCDOT superstreet project, see the project webpage at at

© 2013 Wiser Time Publishing, Inc.

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