HPMS Off Highway (OH) Speed Limits

The Idaho Transportation Department's (ITD) Roads and Highways Road Network Linear Referencing System (LRS) HPMS Off-Highway (OH) speed limits event polyline feature class represents the legally posted regulatory speed limit for each roadway segment included in the HPMS inventory. This attribute indicates the maximum lawful vehicle speed under ideal driving conditions, as displayed on official roadside signs. Speed limit values are expressed in miles per hour (mph) and reflect the prevailing posted speed along each segment. When different speed limits apply to different directions or vehicle classes, the value recorded represents the primary posted limit for passenger vehicles in the predominant direction of travel. This dataset is used by engineers, planners, and safety analysts to evaluate roadway performance, design consistency, and risk exposure. It also supports federal reporting, crash rate normalization, and statewide transportation modeling. The speed limit data is maintained 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. 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