FAQ: Traffic Signal Development in South Carolina - Wells + Associates

FAQ: Traffic Signal Development in South Carolina

Do you have a question about traffic signal approval, design, equipment, or installation in South Carolina? As traffic engineers serving South Carolina, we have the answers here. If you have further questions, please contact us for more information.  

With over 4,000 traffic signals across South Carolina, improvements or modifications to the signalization network may be needed as new land development and real estate development in the region affect the transportation system.   

Q: What role does a traffic engineer with Professional Engineer certification play in traffic signal approval, installation, and modification in South Carolina?

A: If it is determined that a land development project triggers the need for network improvements or impacts existing signal infrastructure, a qualified traffic engineer will need to be consulted to develop new traffic signal installation plans or signal design modifications. All signal plans are required to be signed and sealed by a South Carolina Professional Engineer (PE). (For more information, see our last Question below.) 

Q: Who pays for the design, equipment, and installation of traffic signals in South Carolina?

A: Traffic signals can be very expensive. For private development projects in South Carolina, all costs involving the design, equipment, and installation of new traffic signals and existing signal modifications are the responsibility of the developer. If you want to make sure you are only incurring necessary expenses, and doing so in a cost-effective manner; consulting with a professional engineer can help inform and advocate for your development goals. A qualified engineer can assist with navigating the improvements process, and provide guidance and answers to questions you will want to consider for your project. 

Q: Who is responsible for traffic signals and signal improvements in South Carolina?

A: Within South Carolina, the ownership and maintenance responsibilities of traffic signals vary by location.  The South Carolina Department of Transportation (SCDOT) is responsible for operating the majority of traffic signals within the state, and the remainder are generally operated by larger local municipalities that have in-house traffic management groups.   

In the upstate South Carolina region, cities such as Rock Hill, Greenville, and Spartanburg are responsible for the traffic signals within the city’s municipal limits.  Traffic signals within smaller jurisdictions such as the Town of Fort Mill or Indian Land are typically maintained by the SCDOT.    

Q: How are traffic signal improvements by private developments handled, both in terms of cost and approval?

A: Traffic signal improvements by private developments are coordinated through a Development Agreement process with the public authority responsible for signalization in the area.  All costs involving the design, equipment, and installation of new traffic signals and existing signal modifications for private development are the responsibility of the developer.   

Q: What standards do traffic signals need to comply with in South Carolina?

A: Traffic signal plans are developed in accordance with the Federal Highway Administration’s Manual on Uniform Traffic Control Devices, the SCDOT Traffic Signal Manual, the SCDOT Traffic Signal Design Guidelines, and applicable local jurisdiction requirements. For traffic signals on the SCDOT system, the state maintains a Qualified Products Listings (QPL) for the standard approved equipment to be used with installations.  In addition, many of the local justifications such as Fort Mill and Lancaster County may have agreements with the SCDOT to allow for the installation of nonstandard items such as mast arms or decorative poles at signalized intersection locations.           

Q: How do you ensure traffic signal compliance in South Carolina?

A: The signal plan designs must be prepared by a qualified traffic engineer, and the design process includes the collection of geometric and traffic data, preparation of timing plans, and the preparation of signal plans.  All signal plans are required to be signed and sealed by a South Carolina Professional Engineer (PE).   

Contact Us for Traffic Signal Guidance in South Carolina

The Traffic Design Team at Wells + Associates has a deep understanding of the requirements and regulations for traffic installations, and we work closely with developers and civil engineers to deliver successful traffic signalization projects across the region.  Our team provides a wide array of design services to support traffic signalization for land development including: 

Contact Our South Carolina Transportation Team

Patrick Monroe - Charlotte North Carolina traffic engineer Wells + Associates

Patrick Monroe, P.E.

Regional Manager


As a Professional Engineer licensed in South Carolina and a former Senior Engineering Project Manager at Charlotte Department of Transportation (CDOT), Patrick works with our clients on a wide range of services including traffic signal design, traffic engineering, traffic impact studies, and multimodal transportation planning.

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Larry Sefcik traffic engineer wells + associates

Larry Sefcik

Senior Associate


Larry Sefcik is a veteran of our Traffic Design Services team and has an impressive three decades of experience in traffic signal design and transportation engineering. Before joining Wells + Associates, he worked for the Virginia Department of Transportation (VDOT).

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