Traffic congestion is largely due to the high proportion of solo drivers during peak hours. Ridesharing, in the sense of carpooling, has emerged as a travel mode with the potential to reduce congestion by increasing the average vehicle occupancy rates and reduce the number of vehicles during commuting periods. In this study, we propose a simulation-based optimization framework to explore the potential of subsidizing ridesharing users, drivers, and riders, so as to improve social welfare and reduce congestion. We focus our attention on a realistic case study representative of the morning commute on Sydney’s M4 Motorway in Australia. We synthesize a network model and travel demand data from open data sources and use a multinomial logistic model to capture users’ preferences across different travel roles, including solo drivers, ridesharing drivers, ridesharing passengers, and a reserve option that does not contribute to congestion on the freeway network. We use a link transmission model to simulate traffic congestion on the freeway network and embed a fixed-point algorithm to equilibrate users’ mode choice in the long run within the proposed simulation-based optimization framework. Our numerical results reveal that ridesharing incentives have the potential to improve social welfare and reduce congestion. However, we find that providing too many subsidies to ridesharing users may increase congestion levels and thus be counterproductive from a system performance standpoint. We also investigate the impact of transaction fees to a third-party ridesharing platform on social welfare and traffic congestion. We observe that increasing the transaction fee for ridesharing passengers may help in mitigating congestion effects while improving social welfare in the system.

中文翻译：

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拼车的激励措施：福利和交通拥堵的案例研究

交通拥堵主要是由于高峰时段独自驾驶的比例很高。在拼车的意义上，拼车已成为一种出行方式，有可能通过提高平均车辆占用率和减少通勤期间的车辆数量来减少拥堵。在这项研究中，我们提出了一个基于模拟的优化框架，以探索补贴拼车用户、司机和乘客的潜力，以改善社会福利并减少拥堵。我们将注意力集中在一个代表澳大利亚悉尼 M4 高速公路早上通勤的现实案例研究上。我们从开放数据源合成网络模型和出行需求数据，并使用多项逻辑模型来捕捉用户对不同出行角色的偏好，包括单人司机、拼车司机、拼车乘客，以及不会导致高速公路网络拥堵的预订选项。我们使用链路传输模型来模拟高速公路网络上的交通拥堵，并在提出的基于模拟的优化框架内嵌入定点算法以平衡用户的长期模式选择。我们的数值结果表明，拼车激励措施具有改善社会福利和减少拥堵的潜力。然而，我们发现向拼车用户提供过多补贴可能会增加拥堵程度，因此从系统性能的角度来看会适得其反。我们还调查了第三方拼车平台的交易费用对社会福利和交通拥堵的影响。