Dynamap Traffic Counts
Overview | Data Availability | Data Access | Documentation and Links
Overview
GDT Dynamap Traffic Counts displays two-way Average Daily Traffic (ADT) counts on U.S. Interstates, highways, and on major and residential roads in major metropolitan areas where counts have been taken by government agencies. Data are derived from state Departments of Transportation and city and county governments. Data are available as a point on the street where the count was taken. The data is organized into a statewide shapefile, each point feature having the following attributes:
* street name
* latitude/longitude coordinate (signed, 6 decimal places)
* currency of the data (year)
* historical data (additional year/volume columns)
* name of nearest cross street
* direction to nearest cross-street ('n', 'nw', 'wnw', etc.)
* distance to nearest cross-street (miles, 3 decimal places)
Warning: GDT Dynamap Traffic Counts are licensed for use by NCSU affiliates only. This data is not to be redistributed or used in an Internet Map Server application.
Coordinate System & Datum: The point data is in geographic coordinates/decimal degrees, using NAD 1983.
Data Availability
Time of data: Data is available statewide for 1995. The following locations or areas have additional data availability:
1997: Wilmington area, Rocky Mount area
1994: Hickory area, Durham and Orange Counties (I-40, I-85, 15/501 only), Goldsboro area, Jacksonville area
1993: Asheville area
Point Distribution: Data are available for 22,523 points in North Carolina. Following is availability by greater Triangle county: Wake (1,208), Durham (765), Orange (258), Johnston (212), Chatham (132), Franklin (101).
Data Access
Location: RPP Server
Path: /gdt/traffic File: NXXXTC.SHP
Size: 1.03 mb Format: Shapefile
Projection: Geographic coordinates/decimal degrees Datum: NAD 83
If unable to access the server please contact Data Services for other arrangements.
Tips on Use
Overlay on Streets Data: The Dynamap Traffic Counts point data may not overlay exactly on different street data sources. It may be necessary to relocate points. The data is optimized for use with GDT Dynamap 2000, which is available to NCSU affiliates for class use only and can not be redistributed, used in non-class project work, or used in an Internet Map Server application. To access Dynamp 2000 data for class use contact Steve Morris at 513-2614 or Steven_Morris@ncsu.edu
Using Concurrent Data: The data in the 'Volume' field is not all from the same year. For most locations the data is from 1995. For some locations more recent data is available in the 'Volume' field while the 1995 data is in the 'Volume_1' field. If one wishes to use a concurrent volume data set it may be necessary to create a new field and calculate the 1995 volume values into that field.
Documentation and Links
PDF documentation for GDT Dynamap Traffic Counts is available in the same directory as the data itself (/gdt/traffic) on the RPP Server (filename: traf20.pdf).
Other Links:
GDT Dynamap Traffic Counts page
Libraries Dynamap 2000 data
Go to the Libraries GIS Data List Page
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