The Highway Performance Monitoring System (HPMS) is a national program administered by the Federal Highway Administration (FHWA) that includes data on the condition, performance, use and operating characteristics of the nation's public roadways.  FHWA uses HPMS to apportion federal highway funds, track highway system performance with respect to National Performance Measures (23 CFR 490), and for federal publications such as the annual Highway Statistics publication and the Conditions and Performance Report to Congress. HPMS data is also used widely throughout the transportation community, including other governmental entities, business and industry, and academia. 

    HPMS is comprised of GIS data, tables and summary information submitted by states to FHWA each year. All public roadways are accounted for in HPMS, regardless of ownership. The HGMO section facilitates the submission of HPMS each year and is the authority on state-maintained and non-system mileage for the department.

    GIS Operations

    The NCDOT Linear Referencing System (LRS) is the cornerstone of GIS mapping, analysis and reporting within the department. Linear referencing is a way to store spatial data by locating it along a measured linear feature, such as a route. The NCDOT Linear Referencing System uses the route / milepost referencing method. Each route within a county is assigned a unique Route Id. Milepost measures are calculated along the route based on the length of the road. The NCDOT LRS contains all public and private roads within the state.

    Click here for a guide on the NCDOT 11-digit Route Id.

    The HGMO section uses the LRS to report public and state-maintained mileage including centerline mileage (i.e., road length) and lane miles (i.e., road length multiplied by the number of lanes). We can report using historical, current, or official year-end mileage. There are many nuances to the LRS data and calculating mileage is a complex process. The Road Inventory Data and Reports page contains several standard mileage-based reports created by the HGMO section. You can also contact us for a customized report to better suit your needs.

    The HGMO section is also responsible for maintenance of several different GIS data items:

    • Mile Markers: the location of the physical signs along a highway that depict the distance from the start of the route. Click here to download or view the Mile Markers data.
    • Highway Exits: the location of exits along a highway. This data is part of the Road Characteristics dataset.
    • HPMS Samples and Sample Data Items: random sections of roadway where detailed information is collected and reported as part of the Highway Performance Monitoring System. It is an attribute in the Road Characteristics dataset.
    • MCAP Samples: random tenth mile sections of roadway where detailed information is collected and reported as part of the Maintenance Condition Assessment Program.
    • Road Characteristics Attributes: including Facility Type and Ownership

    Mobile Operations

    The HGMO section supports the Assessments group on all technical aspects of mobile data collection. If you have interest in using mobile devices, such as tablets or iPads to collect spatial data for the department and would like our assistance, please reach out to the Assessments Group to get started.

    For more information Contact Us​.​

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