At some point during the development process in Charlotte, North Carolina you may need a Traffic Impact Study. In this article we explain what a Traffic Impact Study is and how it fits into the real estate project development. 

Traffic impact studies (TIS) are one of three types of transportation assessments that may be required under the City of Charlotte’s Comprehensive Transportation Review (CTR) Guidelines.  Also included are multimodal assessments and transportation demand management assessments.  

City of Charlotte Traffic Impact Study Requirements 

The City of Charlotte states that “the intent of a Traffic Impact Study (TIS) is to identify site-specific and development-related ways to mitigate the vehicular impact of development.” The City has established two thresholds based on the property zoning for determining if a Traffic Impact Study is required during the rezoning or permitting process.  For low intensity zoning districts, a Traffic Impact Study is required for any site that is expected to generate more than 1,500 daily trips or 150 peak hour trips.  For medium to high intensity zoning districts, a Traffic Impact Study is required for any site that is expected to generate more than 2,000 daily trips or 200 peak hour trips.   

Other elements considered in the determination of when a study is needed include: 

• Will the development affect a location with a high vehicle or multimodal crash history? 
• Does the development directly add traffic to a high-congestion intersection? 
• Does the development create the fourth leg of an existing signalized intersection? 
• Does the development exacerbate an already challenging situation such as at a railroad crossing, or does it impact fire station access or school access? 

The Institute of Transportation Engineers states that traffic studies “should be prepared under the supervision of a qualified and experienced transportation professional who has specific training in traffic and transportation engineering and planning.” A traffic study must be prepared and approved by a licensed Professional Engineer (PE).  

What Is a Traffic Impact Study? 

A Traffic Impact Study (TIS) is a document that details the operations and traffic conditions in and around a new proposed development. A TIS will typically assess the following scenarios: 

1. Existing Conditions – Traffic operations as they exist today. 
2. Future Conditions Without the Subject Development – Traffic operations as they will exist in the future without the subject development. This typically accounts for regional growth as well as other approved developments in the vicinity of the site. 
3. Future Conditions with the Subject Development – Traffic operations as will exist in the future with the development’s traffic on the road network. 

With these results, the Traffic Impact Study will typically recommend a series of mitigation strategies to help offset the impacts of the additional traffic generated by the development. Physical mitigation strategies can vary in nature and include things such as: 

• additional lanes for traffic 
• new traffic signals 
• modification or retiming of existing traffic signals 
• enhanced pedestrian and bicycle infrastructure 

In more urban settings where physical mitigation strategies are limited, such as within the LYNX Light Rail Transit Station Areas or Uptown Charlotte, mitigation strategies often need to focus on travel behavior changes. For this very reason, the City of Charlotte has adopted the Unified Development Ordinance (UDO) which includes language requiring developers to plan and implement Transportation Demand Management (TDM) strategies. These efforts in turn reduce the number of vehicle trips generated by a development, thus reducing impacts to the surrounding road network and citywide congestion. 

The requirements and processes for obtaining a traffic impact study are similar in other areas in North Carolina and South Carolina. In Durham, NC, for example, the requirement is called a Traffic Impact Analysis (TIA) and affects developments that are expected to generate at least 150 peak hour vehicle trips. If you have questions about your locality in the Carolinas, don’t hesitate to reach out to us to get an idea of the requirements. 

Contact our Charlotte Traffic Impact Study Engineers

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