HPMS Base Type

The Idaho Transportation Department's (ITD) Roads and Highways Road Network Linear Referencing System (LRS) HPMS base type event polyline feature class represents the material composition of the base course layer located between the pavement surface and the subgrade. This information is collected and maintained as part of ITD’s HPMS inventory to support structural design, performance modeling, and pavement management analysis. The base type attribute describes the construction material used in the base layer, indicating whether it consists of untreated aggregate, stabilized material, asphaltic concrete, lean concrete, or fractured Portland Cement Concrete (PCC). These classifications help assess pavement strength, drainage, and performance characteristics. This dataset is used by engineers, planners, and researchers to evaluate pavement structure adequacy, forecast maintenance needs, and analyze relationships between pavement material types and performance outcomes. It is updated annually as part of ITD’s Highway Performance Monitoring System (HPMS) submittal process to the Federal Highway Administration (FHWA) and reflects current data available from pavement inventory systems, construction records, and design documentation. 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