The emerging autonomous vehicles (AV) can either supplement the public transportation (PT) system or be a competitor with it. This paper focuses on this competition in a hypothetical scenario--"if both AV and PT operators are profit-oriented," and uses an ABM to quantitatively evaluate the system performance in this competition from the perspectives of four stakeholders--AV operator, PT operator, passengers, and public authority. In our model, AV operator updates its supply by changing fleet sizes while PT by adjusting headways, and both use heuristic approaches to update supply in order to increase profits. We implement the model in the first-mile scenario in Tampines. In four regulation scenarios--two by two combinations regarding whether AV and PT are allowed to change supplies--we find that since AV can release the bus operator from low-demand routes, the competition can lead to higher profits of both, and higher system efficiency, simultaneously, rather than a one-sided loss-gain result. For PT, after supply updates, spatially the services are concentrated to short feeder routes directly to the subway station, and temporally concentrated to peak hours. For passengers, the competition reduces their travel time but increases their travel costs. Nonetheless, the generalized travel cost is still reduced when counting the value of time. For system efficiency and sustainability, bus supply adjustment can increase the bus average load and reduce total PCE, while the AV supply adjustment shows the opposite effect. For policy implications, the paper suggests that PT should be allowed to optimize its supply strategies under specific operation goal constraints, and AV operation should be regulated to relieve its externality on the system, including limiting the number of licenses, operation time, and service areas, which makes AV operate like a complementary mode to PT.

中文翻译：

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共享自动驾驶汽车与公共交通的动态交互：竞争视角

新兴的自动驾驶汽车 (AV) 可以补充公共交通 (PT) 系统，也可以与之竞争。本文在一个假设场景——“如果AV和PT运营商都以利润为导向”中关注这场竞争，并使用ABM从四个利益相关者——AV运营商、PT的角度定量评估了这场竞争中的系统性能运营商、乘客和公共当局。在我们的模型中，AV 运营商通过改变车队规模来更新其供应，而 PT 则通过调整车距来更新供应，两者都使用启发式方法来更新供应以增加利润。我们在淡滨尼的第一英里场景中实施该模型。在四种监管场景中——关于是否允许 AV 和 PT 改变供应的二乘二组合——我们发现，由于 AV 可以将公交运营商从低需求路线中解放出来，竞争可以导致两者的更高利润，更高系统效率，而不是片面的损益结果。对于 PT，在供应更新后，服务在空间上集中在直接通往地铁站的短支线路线上，而在时间上则集中在高峰时段。对于乘客来说，竞争减少了他们的旅行时间，但增加了他们的旅行成本。尽管如此，在计算时间价值时，广义旅行成本仍然会降低。对于系统效率和可持续性，母线电源调整可以增加母线平均负载并降低总 PCE，而 AV 电源调整则显示相反的效果。