This paper addresses the problem of operator-based vehicle repositioning in free-floating electric car-sharing systems (FFCSs). New algorithmic techniques are developed which derive cost-effective relocation tours by primarily minimizing relocation drivers’ walking time. Car repositioning takes place overnight and aims at complete rebalancing of the system i.e., at achieving an optimal, based on user demand, cars distribution among non-overlapping cells of the FFCS’s operating area. The battery level of the electric cars is also taken into account when deciding if and where each car will be relocated. If $k$ is the number of employees handling car relocations from oversupplied to undersupplied regions, when $k=1$ i.e., there exists a single employee carrying out a relocation tour comprising alternating phases of a car relocation followed by walking to the next to be relocated car, we define and solve the Minimum Walking Car Repositioning Problem (MWCRP) whose main objective is to minimize the walking distance in the relocation tour as the walking part of such a tour is tiresome and takes more time than the driving one. We also define and solve the $k$ -MWCRP when $k>1$ to handle the case that a team of more than one drivers is employed to take on the relocation plan. It is worth mentioning that these are the first vehicle relocation techniques lowering the relocation cost by mostly minimizing the walking cost. Performance results confirm the effectiveness of the proposed algorithms.

中文翻译：

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优化自由浮动汽车共享系统的搬迁成本

本文解决了自由浮动电动汽车共享系统 (FFCS) 中基于操作员的车辆重新定位问题。开发了新的算法技术，主要通过最大限度地减少搬迁司机的步行时间来获得具有成本效益的搬迁旅行。汽车重新定位在一夜之间进行，旨在完全重新平衡系统，即根据用户需求实现汽车在 FFCS 操作区域的非重叠单元之间的最佳分布。在决定是否以及将每辆汽车重新安置在何处时，还会考虑电动汽车的电池电量。如果 $千$ 是处理汽车从供过于求到供过于求的地区的员工数量，当 $k=1$ 即，存在一名员工执行搬迁之旅，包括汽车搬迁的交替阶段，然后步行到下一辆要搬迁的汽车，我们定义并解决了最小步行汽车重新定位问题（MWCRP），其主要目标是最小化搬迁之旅中的步行距离，因为这种旅行的步行部分很累，而且比开车需要更多时间。我们还定义并解决了 $千$ -MWCRP 当 $k>1$ 处理由一名以上司机组成的团队承担搬迁计划的情况。值得一提的是，这些是第一个通过最大限度地减少步行成本来降低搬迁成本的车辆搬迁技术。性能结果证实了所提出算法的有效性。