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爱达荷州运输部（Idaho Transportation Department，ITD）的《道路与公路路网线性参照系统（Linear Referencing System，LRS）HPMS非公路（Off-Highway，OH）限速事件折线要素类》，代表公路性能监测系统（Highway Performance Monitoring System，HPMS）名录中各道路路段的法定公示监管限速值。该属性表征理想驾驶条件下的合法最高车辆行驶车速，与官方路边限速标识显示的数值一致。限速数值以英里每小时（miles per hour，mph）为单位，反映各路段现行的官方公示限速标准。当不同行驶方向或车辆类别适用不同限速规则时，记录的数值代表主要通行方向下乘用车的主流法定限速。本数据集可供工程师、规划人员与安全分析师用于评估道路运行性能、设计一致性与风险暴露水平，同时可支撑联邦报告编制、事故率归一化处理以及全州交通建模工作。该限速数据作为ITD向联邦公路管理局（Federal Highway Administration，FHWA）提交的公路性能监测系统（HPMS）子项，每年进行维护与更新。本图层为从《道路与公路》系统导出的、仅包含LRS内有效记录的图层，均为当前‘工作’记录。如需获取静态公开数据，请参阅存储于以下网址的记录：https://www.fhwa.dot.gov/policyinformation/hpms.cfm。本内容项为公路性能监测系统（HPMS）权威要素图层的子图层。元数据