Investment timing and length choice for a rail transit line under demand uncertainty
Investment timing and length choice for a rail transit line under demand uncertainty
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DOI：
10.1016/j.trb.2023.102800
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发表时间：
2023-09
期刊：
影响因子：
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通讯作者：
Qianwen Guo;Shumin Chen;Yanshuo Sun;P. Schonfeld
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文献类型：
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作者：
Qianwen Guo;Shumin Chen;Yanshuo Sun;P. Schonfeld
本文的动机是对公共交通基础设施投资的不确定性处理不足。正如过去所观察到的，罕见但戏剧性的事件会严重扰乱公共交通系统的运行，并对公共交通乘客产生负面影响。例如，2019冠状病毒病大流行导致2020年3月美国交通需求下降80%-90%。然而，现有的交通基础设施规划研究并没有模拟这种突然的需求冲击。因此，我们通过将需求演化描述为一个跳跃-扩散过程，即连续时间布朗运动与离散计数过程即泊松过程的结合，提高了不确定交通需求建模的真实感，并提出了在这种不确定性下轨道交通线路发展的解析优化模型。我们共同优化了两个相关决策，即引入轨道交通到通勤走廊的时机和铁路线的长度选择。我们驳斥一种误解，即如果预期在规划期内节省成本，项目投资应该立即开始。我们还发现，投资时机和规模决策是密切相关的，并且在某些参数（如基础设施建设周期）相同的变化下表现得截然不同。所建立的模型和分析框架可推广应用于其他不确定条件下的民用基础设施开发和投资问题。
This paper is motivated by the inadequate treatment of uncertainty in public transit infrastructure investments. As observed in the past, rare but dramatic events can heavily disrupt public transit system operations and negatively affect the transit riders. For example, the COVID-19 pandemic caused an 80%-90% transit demand decline in March 2020 in the U.S. However, the existing transit infrastructure planning studies have not modeled such sudden demand shocks. We thus improve the modeling realism of uncertain transit demand by formulating demand evolution as a jump-diffusion process, which is a combination of continuous-time Brownian motion and a discrete counting process, namely Poisson process, and present analytical optimization models for the development of a rail transit line under such uncertainty. We jointly optimize two related decisions, namely the timing for introducing rail transit to a commuter corridor and length choice for the rail line. We refute a misconception that investment in a project should always start immediately if a positive cost saving over the planning horizon is expected. We also find that investment timing and sizing decisions are closely related and behave quite differently for the same change in some parameters, such as the infrastructure construction period. The developed modeling and analysis framework should be transferable to other civil infrastructure development and investment problems under uncertainty.