Ridesharing and fleet sizing for On-Demand Multimodal Transit Systems
Ridesharing and fleet sizing for On-Demand Multimodal Transit Systems
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DOI：
10.1016/j.trc.2022.103594
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发表时间：
2021-01
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影响因子：
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通讯作者：
Ramon Auad-Perez;P. Van Hentenryck
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文献类型：
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作者：
Ramon Auad-Perez;P. Van Hentenryck
本文考虑按需多式联运系统（ODMTS）的设计，结合联合收割机固定的公交/铁路线路之间的交通枢纽与按需穿梭服务的第一/最后一英里/从枢纽。设计问题的目的是找到一个网络设计的固定路线，让一组乘客从他们的起源地旅行到他们的目的地，同时最小化的旅行成本，巴士运营成本和乘客旅行时间的总和。本文讨论了现有的工具设计ODMTS的两个差距。首先，它概括了以前的工作，包括乘坐共享的航天飞机乘坐。其次，它提出了新的车队规模算法，以确定所需的航天飞机的数量，以满足性能指标的ODMTS设计。这两个贡献都是基于混合型多学科计划（MIP）。对于ODMTS设计，MIP会考虑上下车路线，以捕获共乘，将往返于同一枢纽的乘客分组。船队规模优化问题被建模为一个带覆盖约束的最小流问题。自然公式导致密集图和计算问题，这是通过在稀疏图上工作的重新公式来解决的。方法的贡献进行评估的真实的案例研究：公共交通系统的更广泛的安阿伯和伊普西兰蒂地区在密歇根州。结果表明，ODMTS的共乘的巨大潜力，因为成本降低了约26%，相对于只允许个人乘坐航天飞机，在运输时间增加最小的代价。与现有系统相比，设计的ODMTS还将成本降低了35%，并将运输时间缩短了38%。
This paper considers the design of On-Demand Multimodal Transit Systems (ODMTS) that combine fixed bus/rail routes between transit hubs with on-demand shuttles that serve the first/last miles to/from the hubs. The design problem aims at finding a network design for the fixed routes to allow a set of riders to travel from their origins to their destinations, while minimizing the sum of the travel costs, the bus operating costs, and rider travel times. The paper addresses two gaps in existing tools for designing ODMTS. First, it generalizes prior work by including ridesharing in the shuttle rides. Second, it proposes novel fleet-sizing algorithms for determining the number of shuttles needed to meet the performance metrics of the ODMTS design. Both contributions are based on Mixed-Integer Programs (MIP). For the ODMTS design, the MIP reasons about pickup and dropoff routes in order to capture ridesharing, grouping riders who travel to/from the same hub. The fleet-sizing optimization is modeled as a minimum flow problem with covering constraints. The natural formulation leads to a dense graph and computational issues, which is addressed by a reformulation that works on a sparse graph. The methodological contributions are evaluated on a real case study: the public transit system of the broader Ann Arbor and Ypsilanti region in Michigan. The results demonstrate the substantial potential of ridesharing for ODMTS, as costs are reduced by about 26% with respect to allowing only individual shuttle rides, at the expense of a minimal increase in transit times. Compared to the existing system, the designed ODMTS also cuts down costs by 35% and reduces transit times by 38%.