Department of Engineering and Public Policy and Department of Mechanical Engineering, Carnegie Mellon University, Baker Hall 129, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, United States.
Department of Engineering and Public Policy and Department of Mechanical Engineering, Carnegie Mellon University, Baker Hall 129F, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, United States.
Environ Sci Technol. 2021 Oct 5;55(19):13174-13185. doi: 10.1021/acs.est.1c01641. Epub 2021 Sep 20.
On-demand ridesourcing services from transportation network companies (TNCs), such as Uber and Lyft, have reshaped urban travel and changed externality costs from vehicle emissions, congestion, crashes, and noise. To quantify these changes, we simulate replacing private vehicle travel with TNCs in six U.S. cities. On average, we find a 50-60% decline in air pollutant emission externalities from NO, PM, and VOCs due to avoided "cold starts" and relatively newer, lower-emitting TNC vehicles. However, increased vehicle travel from deadheading creates a ∼20% increase in fuel consumption and associated greenhouse gas emissions and a ∼60% increase in external costs from congestion, crashes, and noise. Overall, shifting private travel to TNCs increases external costs by 30-35% (adding 32-37 ¢ of external costs per trip, on average). This change in externalities increases threefold when TNCs displace transit or active transport, drops by 16-17% when TNC vehicles are zero-emission electric, and potentially results in reduced externalities when TNC rides are pooled.
按需叫车服务（如优步和来福车）的出现改变了城市交通模式，也改变了车辆排放、拥堵、事故和噪音等外部性成本的分布。为了量化这些变化，我们模拟了在美国六个城市用叫车服务替代私人汽车出行的情景。结果发现，由于避免了“冷启动”且车辆相对较新、排放量较低，NO、PM 和 VOC 等空气污染物的排放外部性降低了 50-60%。然而，空驶车辆的增加导致燃料消耗和相关温室气体排放增加了约 20%，拥堵、事故和噪音造成的外部成本增加了约 60%。总体而言，将私人出行转移到叫车服务上会增加 30-35%的外部成本（平均每趟行程增加 32-37 美分的外部成本）。当叫车服务取代公共交通或非机动交通时，外部性的变化会增加三倍，当叫车服务车辆为零排放电动汽车时，外部性的变化会减少 16-17%，而当叫车服务的合乘车辆增多时，外部性可能会减少。
