Strategic Highway Network (STRAHNET)

The Strategic Highway Network (STRAHNET) dataset and its geometries was updated on August 08, 2025 from the Federal Highway Administration (FHWA) and is part of the U.S. Department of Transportation (USDOT)/Bureau of Transportation Statistics (BTS) National Transportation Atlas Database (NTAD). The layer represents the Strategic Highway Network (STRAHNET). The STRAHNET is a subset of the National Highway System (NHS) and includes information such as road segments, direction, build date, state codes, functional classification, ownership, and other attributes related to highways in the United States. The provided information outlines the preparation of a layer that represents the National Highway System (NHS) in the context of the HPMS 2020 Geometric network and attribute definition source HPMS 2020. The NHS layer incorporates attributes from HPMS, and the conflation process involves the transfer of State_Code, Year_Record, Route_ID, Begin_Point, End_Point, and F_SYSTEM fields. Calibration of Begin_Point and End_Point is performed based on shape length and sequence for split links. The minimum positional accuracy is specified at a spatial resolution of 1:100,000 or better, although most state-submitted data ranges between 1:5,000 to 1:10,000. The spatial data organization method is described as a vector using the SDTS (Spatial Data Transfer Standard) Point and Vector Object Type with a count of 626,366 objects. The coordinate system is defined in geographic terms with a horizontal datum of D WGS 1984, employing decimal degrees for latitude and longitude. The entity and attribute information is comprehensive, covering various aspects of the NHS and HPMS data. A data dictionary, or other source of attribute information, is accessible at https://doi.org/10.21949/1529838