NCDOT Traffic Survey Group
North Carolina’s Traffic Survey Group is the traffic data provider for the Department of Transportation. This group collects traffic data statewide to analyze and support planning, design, construction, maintenance, operation, and research activities required to manage the transportation system in North Carolina.
Annual Average Daily Traffic (AADT) Traffic Volume
Update:The AADT Stations Shapefile now provides 2013 AADT Traffic Volume data.
Annual Average Daily Traffic (AADT) Traffic Volume Map presents the traffic average for the year at specific points on North Carolina highways. Data is collected at more than 40,000 locations throughout North Carolina using Portable Traffic Count Stations. AADT map is typically published at the later part of the summer. This report complies with standards outlined in the Federal Highway Administration Traffic Monitoring Guide.
The AADT maps are published once the data for the entire state has been collected, analyzed and processed. Publication typically occurs towards the later part of the summer.
With more than 40,000 Portable Traffic Count (PTC) Stations located throughout North Carolina, Traffic Survey has adopted the following data collection schedule:
- Interstate route volumes are collected on an annual basis with the exception of stations which fall within the off cycle urban areas - refer to urban area cycle below. *Reference county maps for the most current Interstate data within off cycle urban area. (Off cycle means the year in which data will not be collected.) *Reference urban maps for the most current Interstate data within on cycle urban area. (On cycle means the year in which data will be collected.)
- US and NC route volumes are also collected on an annual basis with the exception of stations which fall within the off cycle urban areas - refer to urban area cycle below.
- Secondary Road (SR) volumes are collected on a biennial cycle with approximately half being counted each year. If a particular secondary road is not available for the most current year, it may be available for the prior year.
- North Carolina’s eighteen largest urban areas are counted on a biennial cycle with 10 urban areas counted during the even years and 8 urban areas counted during the odd years.
- Urban Area Cycle (even year): Asheville, Charlotte, Concord-Kannapolis, Fayetteville, Gastonia, Goldsboro, Greenville, Jacksonville
- Urban Area Cycle (odd year): Burlington, Chapel Hill, Durham, Greensboro, Hickory, High Point, Raleigh, Rocky Mount, Wilmington, Winston-Salem
- Not all roads have portable traffic count stations located on them
- With the exception of Interstate, NC and US routes, NCDOT County Maps refer to roads using a four digit Secondary Road Number, not a road’s local name
- To locate a secondary road number and/or name of a road, use Secondary Roads Database Lookup. This database provides a cross-index of Road Name and Secondary Road number. Select a county to restrict your search.
AADT Traffic Volume Maps Shape File
All data is provided in ArcGIS format and is viewable using ArcView or ArcMap software (www.esri.com).
Disclaimer related to the spatial accuracy of this file:
- Data in this file was digitized referencing the available NCDOT GIS Data Layer, LRS Arcs Shapefile Format from Quarter 1 release and is not the result of using GPS equipment in the field. North Carolina Department of Transportation shall not be held liable for any errors in this data. This includes errors of omission, commission, errors concerning the content of data, and relative positional accuracy of the data. This data cannot be construed to be a legal document.
Traffic Data Requests
All data is provided in ArcGIS format and is viewable using ArcView or ArcMap software (www.esri.com). We encourage our customers to use our online AADT maps or our AADT reports found in the Product Links box. Using these resources will enable our customers to receive AADT data when they need it. However, if you still need the assistance of our office, please contact our Traffic Data Request Line.
When requesting traffic data, please provide the following information: (see example below)
- County in which the request is located
- City or Town (if applicable) in which the request is located
- Nearest intersecting road to the request location
- Wake County
- City of Raleigh
- I-440 (location of the count request)
- SR 1005 - Six Forks Rd (nearest intersecting road)
Please do not use an address, block number, distance or GPS when describing location.
Traffic Monitoring Programs
The Traffic Survey Group (TSG) Organizes traffic monitoring activities based on the model provided by the Traffic Monitoring Guide (TMG) published by the Federal Highway Administration (FHWA). Activities are coordinated under the following three programs:
- Coverage Count Program - This program consists of statewide coverage of short-term (48-hour) Portable Traffic Counts (PTC). There are approximately 40,000 PTC monitoring stations located throughout the state. Data is collected on both state and locally maintained roadways throughout the state. These counts are factored into Annual Average Daily Traffic (AADT) volumes using seasonal and classification data from other TSG programs. The Primary Routes (Interstate, US and NC) are collected each year while the secondary routes are collected on a two-year cycle with half being collected each year. Stations located within North Carolina’s 18 major Urbanized Areas are collected on a two-year cycle, with nine urban areas being collected each year. Stations designated either as small urban (areas under 50,000 in population) or rural are organized and collected by county each year.
Other elements of the Coverage Count Program include:
- Seasonal data is collected throughout the state from a sample of PTC stations four to five times per year for the purpose of updating the assignment of all stations into their prospective seasonal groups. A station's seasonal assignment is one of the factors used in estimating AADT.
- Interstate data is collected and analyzed using a combination of mainline control station and ramp station counts. Segments are estimated by balancing ramp volumes between each of the known mainline stations. AADT’s are estimated for interstate routes every year.
- Portable Vehicle Class (PVC) coverage is a new product currently being developed at this time in order to support the growing need for this data type and to meet FHWA monitoring requirements. It is planned that PVC data will be collected for the standard FHWA vehicle classifications by hour over a 48- hour period throughout the state on a 3-year cycle. Traffic Survey has just recently started expanding the number of data collection sites to support this process and provide a comprehensive coverage of our Statewide Highway System.
- Continuous Count Program - This program consists of permanent traffic monitoring stations that are used to collect traffic data 24 hours a day and 365 days a year on a sample of roadways throughout the state. The data collected at these stations is used to generate seasonal factors for the Coverage Count Program, are reported to the Federal Highway Administration for trend analyses, Highway Performance Management System reporting, cost allocation reporting and to support pavement design research and project planning studies. These stations provide a comprehensive understanding of traffic flow characteristics at each location.
- Projects Count Program - Project Counts range in magnitude from a simple bridge replacement to a very complex regional transportation model and is scheduled in coordination with the customer. Traffic data is requested to support a variety of planning and engineering studies and provides traffic count services for traffic forecasting, research projects, area transportation planning studies, and work zone design studies. The data collected may include hourly volume, hourly vehicle class, manual class, and turning movement data. In addition, special projects are sometimes designed to suite the customer’s data need.
Research & Development:
A Spatial Editing and Validation Process for Short Count Traffic Data
Prototype Demonstration of a Geographic Information System Application for the Seasonal Analysis of Traffic Data, Development of Seasonal Factors and Seasonal Adjustment of Roadways.
A method for updating seasonal groups for traffic count locations using an ArcView Geographical Information System application.
TMS Perferred Rule Set Reference Material:
The information below is for potential TMS vendors who are interested in providing an RFP. These items are examples of reports, graphs, and preferred rules. This information is a sample of potential work and is not ready for complete publication.
- E-Mail: Contact Us
- Phone during office hours:
8:00 a.m. - 5:00 p.m.
- Mail / Courier
1547 Mail Service Center,
Raleigh NC, 27699-1547
750 N. Greenfield Parkway,
Garner NC, 27529
Traffic Data Request Line:
- E-Mail: Contact Us
- Phone during office hours:
8:00 a.m. - 5:00 p.m.
Toll Free: 1-877-DOT-4YOU