In the MaaS (Mobility as a Service) age, the alternatives of route choice for a trip will not be the single mode paths, but the combined routes utilizing more than one travel mode in the multi-modal transportation systems. When modeling the multi-modal combined route choices, alternative routes are correlated not only because of the overlapping of physical links, but also because of the overlapping of travel modes. We define this problem as the generalized path overlapping problem. To address the generalized overlapping problem, a multi-modal logit kernel (MLK) model is proposed to explicitly consider the correlations of unobserved utilities of combined routes. In this model, the unobserved utilities of combined routes are divided to two parts, the link specific parts and the independent route specific parts. The link specific parts are further divided to two parts: physical link specific and the mode specific. The generalized path overlapping problem is captured by the sharing of these two parts of unobserved link utilities. Based on this model, the stochastic user equilibrium on multi-model transport networks is represented as a fixed-point problem. Numerical studies are designed to illustrate the effects of incorporating generalized overlapping problem on disaggregated route choice prediction and aggregated traffic flow assignment. With different settings of physical link and mode specific error terms, the variations of disaggregated route choice predictions and aggregated traffic flows are discussed. It is found that, the generalized overlapping problem can be captured by the proposed model and significantly affect both the individual route choice predictions and aggregated traffic flows at equilibrium.

中文翻译：

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考虑广义路径重叠问题的MaaS时代多模态组合路径选择建模


在MaaS（出行即服务）时代，出行的路线选择将不再是单一模式路径，而是多式联运系统中利用多种出行模式的组合路线。在对多模式组合路线选择进行建模时，替代路线之间的相关性不仅是因为物理链路的重叠，而且还因为出行模式的重叠。我们将这个问题定义为广义路径重叠问题。为了解决广义重叠问题，提出了多模态 Logit 核（MLK）模型来明确考虑组合路线的未观察效用的相关性。在该模型中，组合路线的不可观测效用被分为两部分：链路特定部分和独立路线特定部分。链路特定部分进一步分为两部分：物理链路特定和模式特定。广义路径重叠问题是通过共享未观察到的链接实用程序的这两部分来捕获的。基于该模型，多模型传输网络上的随机用户均衡被表示为一个不动点问题。数值研究旨在说明合并广义重叠问题对分类路线选择预测和聚合交通流分配的影响。通过物理链路和模式特定误差项的不同设置，讨论了分类路线选择预测和聚合流量的变化。研究发现，所提出的模型可以捕获广义重叠问题，并显着影响个体路线选择预测和均衡状态下的聚合交通流。