HPMS Base Thickness

The Idaho Transportation Department's (ITD) Roads and Highways Road Network Linear Referencing System (LRS) HPMS base thickness event polyline feature class represents the thickness of the lowest pavement layer, commonly referred to as the base course, beneath the surface layer of the roadway. This information is collected and maintained as part of the HPMS inventory to support structural design, performance modeling, and pavement condition assessment. The base thickness attribute indicates the compacted depth of granular, stabilized, or treated material placed directly on the subgrade to provide load distribution and structural support. Thickness values are typically expressed in inches and derived from design plans, as built documentation, or pavement management system records. This dataset is used by engineers, planners, and researchers for evaluating pavement structure adequacy, forecasting maintenance needs, and analyzing the relationship between pavement design and performance. 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 and design records. 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考系统（Linear Referencing System, LRS）HPMS基层厚度事件折线要素类，用于表征路面表层下方的最下层路面（通常称为基层（base course））的厚度。该信息作为公路性能监测系统（Highway Performance Monitoring System, HPMS）台账的组成部分进行收集与维护，旨在支撑路面结构设计、性能建模与路面状况评估工作。其中的基层厚度属性，表示直接铺筑于路基（subgrade）之上、用于实现荷载分布与结构支撑的粒料、稳定化或经处理材料的压实厚度。厚度数值通常以英寸为单位，其来源包括设计图纸、竣工文件或路面管理系统的记录。该数据集可供工程师、规划人员与研究人员用于评估路面结构适用性、预测养护需求，以及分析路面设计与路面性能之间的关联关系。本数据集每年作为ITD向美国联邦公路管理局（Federal Highway Administration, FHWA）提交HPMS数据流程的一部分进行更新，可反映路面台账系统与设计记录中的最新可用数据。本图层为Roads and Highways系统导出的内容，仅包含LRS中的有效记录，即当前的「工作」台账记录。如需获取静态发布的官方数据，请访问以下地址存储的记录：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