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AADT Source Type Definitions

This documentation outlines the process of understanding the AADT Source Type field within the Intersection AADTs and Road Segment AADTs modules.

1. Access Intersection or Road Segment AADTs​

Navigate to either Intersection or Road Segment AADTs module from the menu

2. Select Source Type Field​

One of the fields for each road segment is Source Type. Users can view, filter, and group by AADT source type values and refer to these definitions:

  • Count: The location is counted in the subject year, and the AADT is calculated from the count using AADT factors.

  • Growth from Count: The location is not counted in the subject year. However, one historical count exist for the location, and the AADT is calculated using the historical count AADT by applying a default growth factor (e.g. 2%).

  • Linear Regression: The location is not counted in the subject year. However, two or more historical counts exist for the location, and the AADT is calculated using the historical counts AADTs by applying a linear regression model.

  • Corridor: The location is not counted in the subject year, and no historical counts exist for the location. However, counts exist on the other road segments along the same corridor for the subject year, and AADTs from those counts are passed along to the subject location.

  • Single Intersection: The location is not counted in the subject year, and no historical counts exist for the location. However, a count exist on one side adjacent intersection for the subject year, and the AADT is calculated using the TMC and the AADT factors from that intersection for the subject location.

  • Intersection Average: The location is not counted in the subject year, and no historical counts exist for the location. However, counts exist on the two sides adjacent intersections for the subject year, and the average AADT is calculated using the TMCs and the AADT factors from those intersections for the subject location.

  • Growth from Prediction: The location is not counted in the subject year, and no historical counts exist for the location. The AADT is calculated using any available historical prediction by applying a linear regression model.

  • User Modified: The AADT is entered by user based on Engineering judgement. This usually occurs when the predicted AADT is not as expected, or no AADT is predicted for the location for the subject year.

  • User Modified Permanent: A permanent AADT is entered by user based on Engineering judgement. When an AADT is permanent it won’t change by running future years AADT prediction, and It functions in a way similar to count.

  • TesHistorical: A historical count coming from TES Windows.

  • Unknown: The source is unknown. This could occur for the older AADTs.