National Truck Network

The Idaho Transportation Department's (ITD) Roads and Highways Road Network Linear Referencing System (LRS) national truck network event polyline feature class, also known as the National Network, was authorized by the Surface Transportation Assistance Act of 1982 (P.L. 97-424) and specified in the U.S. Code of Federal Regulations (23 CFR 658) to require states to allow conventional combinations on "the Interstate System and those portions of the Federal-aid Primary System ... serving to link principal cities and densely developed portions of the States ... [on] high volume route[s] utilized extensively by large vehicles for interstate commerce ... [which do] not have any unusual characteristics causing current or anticipated safety problems." Conventional combinations are tractors with one semitrailer up to 48 feet in length or with one 28-foot semitrailer and one 28-foot trailer, and can be up to 102 inches wide. The National Network differs in extent and purpose from the National Highway System (NHS), which was created more than a decade later by the National Highway System Designation Act of 1995 (P.L. 104-59). Both are about the same length, roughly 200,000 miles, but the National Network includes approximately 65,000 miles of highways beyond the NHS, and the NHS includes about 50,000 miles of highways that are not on the National Network. The National Network supports interstate commerce by regulating the size of trucks, while the NHS supports interstate commerce by focusing federal investments. The National Network has not changed significantly in a quarter century. It is modified only if segments are added to the Interstate highway system or if states petition to have a segment beyond the Interstate highway system added or deleted. Petitions for modifications have not been received in years, even though the geography of interstate commerce has changed significantly with the growth of smaller communities into principal cities and the emergence of new, densely developed areas. Consistency between the National Network and the freight-related portions of the more recent NHS is not required. The definition of conventional combinations is also unchanged, even though 48-feet is no longer the maximum length of a single trailer in the majority of states. Single 53-foot trailers are allowed in 25 states without special permits and in an additional 3 states subjects to limits on distance of kingpin to rearmost axle. 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 Planning - Freight and Rail authoritative feature layer. Metadata爱达荷州运输部（Idaho Transportation Department, ITD）的道路与公路网线性参考系统（Linear Referencing System, LRS）国家卡车网络事件折线要素类（又称国家路网），是依据1982年《地面运输援助法》（公法97-424）授权，并在美国联邦法规汇编第23篇第658节（23 CFR 658）中明确规定的数据集。该法规要求各州允许常规组合车辆在「州际公路系统及联邦援助干线系统中连接主要城市与州内高密度开发区域的路段……以及那些被大型车辆广泛用于州际货运的高流量路段……且不存在引发当前或预期安全问题的异常特征」的道路上通行。常规组合车辆指牵引一辆最长48英尺半挂车，或牵引一辆28英尺半挂车与一辆28英尺挂车的牵引车组合，最大宽度可达102英寸。 国家路网与十余年后出台的1995年《国家公路系统指定法》（公法104-59）确立的国家公路系统（National Highway System, NHS）在覆盖范围与用途上存在显著差异。二者总长度相近，均约20万英里，但国家路网包含约6.5万英里超出国家公路系统覆盖范围的公路，而国家公路系统另有约5万英里路段未纳入国家路网。国家路网通过监管卡车尺寸支持州际货运，国家公路系统则通过投入联邦资金助力州际货运发展。 国家路网近25年来未发生显著变化，仅当州际公路系统新增路段，或各州申请新增、删除州际公路系统外的路段时才会进行调整。尽管州际货运的地理格局已发生显著变化——小社区发展为主要城市，新的高密度开发区域不断涌现，但多年来未收到任何修改申请。国家路网与更新近的国家公路系统的货运相关部分之间并不要求保持一致性。 常规组合车辆的定义也未发生改变，尽管目前多数州已不再将48英尺作为单挂车的最大长度。现有25个州无需特殊许可即可使用53英尺单挂车，另有3个州允许使用53英尺单挂车，但对牵引销至最后车轴的距离设有限制。 本图层为从道路与公路系统导出的内容，仅包含线性参考系统中的有效记录，属于「规划-货运与铁路」权威要素图层的子图层，附带元数据。