标题： 城市公共交通系统中混合运输单元的动态容量分配用于货物搭便车 显示英文标题

标题： Dynamic capacity allocation of hybrid transportation units for cargo-hitching in urban public transportation systems

摘要： 为提高非高峰时段公共交通系统（PTSs）的利用率，我们提出一个算法框架，该框架设计具有混合运输单元（HTUs）的PTSs，这些单元可以通过灵活的内部结构运输乘客或货物。 在此背景下，我们研究了一个容量网络设计问题，以在现有的PTSs中实现货物搭便车。 具体而言，我们研究了一个固定车辆路线和时刻表的场景，在此场景中，车辆可以配备HTUs以实现货物搭便车。 我们从总成本的角度优化网络设计，以考虑与HTUs投资相关的标准化网络设计成本和货运路由成本。 我们提出一个算法框架，该框架在空间和时间扩展的分层图中编码了问题的一些约束，并使用定价与分支算法解决由此产生的网络设计问题。 我们将这个框架应用于基于慕尼黑市地铁网络的案例研究。 我们的算法在规模上比商业求解器大六倍，并且对于所有实例，其整数可行解的中位数整数间隙小于1.02%。 我们证明，使用HTUs的货物搭便车提高了PTSs的利用率，尤其是在非高峰时段，而不会影响乘客服务水平和质量。 此外，我们进行了一项敏感性分析，表明如果基于卡车的运输产生超过每辆车每公里1.6欧元的外部成本，并且装卸成本低于每乘客当量2欧元，则货物搭便车是值得的。 显示英文摘要

摘要： To improve the utilization of public transportation systems (PTSs) during off-peak hours, we present an algorithmic framework that designs PTSs with hybrid transportation units (HTUs), which can transport passengers or freight by leveraging a flexible interior. Against this background, we study a capacitated network design problem to enable cargo-hitching in existing PTSs. Specifically, we study a setting with fixed vehicle routes and timetables in which vehicles can be equipped with HTUs to enable cargo-hitching. We optimize the network design from a total cost perspective to account for normalized network design costs tied to the investment in HTUs and freight routing costs. We present an algorithmic framework that encodes some of the problem's constraints in a spatially and temporally expanded, layered graph, and solves the resulting network design problem with a price-and-branch algorithm. We apply this framework to a case study based on the subway network in the city of Munich. Our algorithm outscales commercial solvers by a factor of six and yields integer feasible solutions with a median integrality gap of less than 1.02% for all instances. We show that cargo-hitching with HTUs increases the utilization of PTSs, especially during off-peak hours, without cannibalizing passenger service level and quality. Moreover, we present a sensitivity analysis that indicates that cargo-hitching is worthwhile if truck-based transport occurs at an externality cost of more than EUR 1.6 per vehicle and kilometer and loading and unloading costs of less than EUR 2 per passenger equivalent.