HPMS Median

The Idaho Transportation Department's (ITD) Roads and Highways Road Network Linear Referencing System (LRS) HPMS median event polyline feature class identifies the type of median separating opposing lanes of traffic along divided highways. Medians improve safety and operations by reducing head-on collisions, minimizing interference from opposing traffic, and providing space for recovery, emergency stops, and potential future lanes. This information is collected from roadway design plans, construction as-built documents, and ITD’s roadway inventory systems in accordance with FHWA HPMS Field Manual coding guidance. Each median is classified by physical type and barrier characteristics. Medians may include unprotected areas, curbed separators, or positive barriers that prevent vehicle crossover. Optional sub-codes describe the rigidity of barrier types (flexible, semi-rigid, or rigid) when that level of detail is available. The dataset supports roadway safety evaluation, network inventory, and performance reporting. It is maintained and updated annually as part of ITD’s Highway Performance Monitoring System (HPMS) submission 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）的道路与高速公路路网线性参照系统（Linear Referencing System, LRS）高速公路性能监测系统（Highway Performance Monitoring System, HPMS）中央分隔带事件折线要素类，用于识别分隔双向高速公路对向行车道的中央分隔带类型。中央分隔带可通过减少正面碰撞、降低对向车流干扰，以及为车辆避险、应急停靠及未来新增车道预留空间，提升道路安全性与通行效率。本数据集的信息依据美国联邦公路管理局（Federal Highway Administration, FHWA）《HPMS现场手册》的编码规范，从道路设计图纸、施工竣工文件及ITD道路库存系统中采集获取。每处中央分隔带均按实体类型与护栏属性进行分类，涵盖无防护区域、路缘分隔带，以及可防止车辆越界的实体防护护栏。若可获取该层级细节，可选子代码可用于标注护栏类型的刚度等级（柔性、半刚性或刚性）。本数据集可支撑道路安全评估、路网库存管理及绩效报告编制工作。作为ITD向美国联邦公路管理局（FHWA）提交的高速公路性能监测系统（HPMS）工作的一部分，本数据集每年进行维护与更新。本图层为道路与高速公路（Roads and Highways）系统的导出产物，仅包含线性参照系统（LRS）内的有效记录，即当前的“运行中”记录。如需获取静态发布数据，请查阅存储于以下链接的记录：https://www.fhwa.dot.gov/policyinformation/hpms.cfm。本内容项为高速公路性能监测系统（HPMS）权威要素图层的子图层。元数据