Route Dominance

The Idaho Transportation Department's (ITD) Roads and Highways Road Network Linear Referencing System (LRS) HPMS route dominance event polyline feature class designates which route is considered dominant when two or more signed routes overlap along the same roadway segment. This determination ensures consistency in reporting, mapping, and data analysis for overlapping corridors such as Interstate, U.S., and State routes. Dominance is typically assigned based on route hierarchy (Interstate, U.S., State, then Local), functional classification, and direction of inventory. When multiple concurrent routes exist, the dominant route is coded for inventory and data attribution purposes, while the subordinate routes are tracked as concurrent. This dataset supports system inventory accuracy, reduces duplication, and maintains consistency across route-based reporting and HPMS submissions. It is reviewed and updated annually as part of ITD’s Highway Performance Monitoring System (HPMS) submittal to the Federal Highway Administration (FHWA). This layer is an export from Roads and Highways that represents only the active records within the LRS. This content item is a sub-layer of the Road Network - Other authoritative feature layer. Metadata