HPMS Last Overlay

The Idaho Transportation Department's (ITD) Roads and Highways Road Network Linear Referencing System (LRS) HPMS last overlay event polyline feature class identifies the compacted depth of the most recent pavement layer placed over an existing roadway surface during an overlay or resurfacing project. This value reflects the thickness of new asphalt or Portland Cement Concrete (PCC) material added to restore structural integrity, ride quality, and service life. Thickness data is derived from project construction documentation, pavement design plans, and ITD’s pavement management systems. For asphalt overlays, thickness represents the compacted depth of new hot mix asphalt placed on the existing pavement. For concrete overlays, it represents the finished depth of the new concrete layer above the previous surface. This dataset is used by engineers, pavement managers, and analysts to evaluate the structural adequacy of resurfaced pavements, estimate remaining service life, and support performance modeling. It also assists in determining maintenance timing, comparing design versus constructed conditions, and verifying consistency with HPMS data submissions to the Federal Highway Administration (FHWA). Updates occur annually as part of ITD’s Highway Performance Monitoring System (HPMS) submittal cycle using the most current pavement project and inventory information. This layer is an export from Roads and Highways that represents only the active records within the LRS. These are current “working” records. For the static, published data, please see the records stored at: https://www.fhwa.dot.gov/policyinformation/hpms.cfm This content item is a sub-layer of the Highway Performance Monitoring System (HPMS) authoritative feature layer. Metadata