Freight transportation network is an essential backbone for supporting the industrial activities and economic developments of the nation and global trade. In this paper, we extend the network-based measures recently developed by Xu et al. (2018) for assessing freight transportation network redundancy – an important component in making freight transportation networks more robust and resilient against disruptions. Redundancy of freight transportation networks is characterized by two network-based measures. The route diversity measure evaluates the existence of multiple efficient routes available for freight users or the degree of connections between a specific origin-destination (O-D) pair, while the network spare capacity measure quantifies the network-wide spare capacity with an explicit consideration of congestion effect and modal split. These two measures can complement each other by providing a two-dimensional characterization of freight transportation network redundancy that can be used to provide information to freight users as well as to assist network planners in making future infrastructure investment decisions to enhance the redundancy of freight transportation networks. A case study of the Utah freight network for transporting coal is provided to demonstrate the features of the two network-based redundancy measures as well as the applicability of assessing the redundancy of freight transportation networks. The analyses reveal that the two measures provide useful results from two perspectives that may be of benefit to freight carriers and transportation system planners.

货运网络是支持国家和全球贸易的工业活动和经济发展的重要支柱。在本文中，我们扩展了 Xu 等人最近开发的基于网络的措施。(2018) 用于评估货运网络冗余——这是使货运网络更加强大和抵御中断的重要组成部分。货运网络冗余的特点是两种基于网络的措施。路线多样性衡量指标评估货运用户是否存在多条有效路线或特定起点-目的地 (OD) 对之间的连接程度，而网络备用容量衡量则在明确考虑拥堵的情况下量化网络范围的备用容量效果和模态分割。这两项措施可以通过提供货运网络冗余度的二维表征来相互补充，可用于向货运用户提供信息，并协助网络规划者制定未来的基础设施投资决策，以增强货运网络的冗余度. 以犹他州煤炭运输网络为例，展示了两种基于网络的冗余措施的特点以及评估货运网络冗余的适用性。分析表明，这两项措施从两个角度提供了有用的结果，可能对货运承运人和运输系统规划者有益。