User Equilibrium is the standard representation of the so-called routing game in which drivers adjust their route choices to arrive at their destinations as fast as possible. Asking whether this Equilibrium is strong or not was meaningless for human drivers who did not form coalitions due to technical and behavioral constraints. This is no longer the case for connected autonomous vehicles (CAVs), which will be able to communicate and collaborate to jointly form routing coalitions. We demonstrate this for the first time on a carefully designed toy-network example, where a `club` of three autonomous vehicles jointly decides to deviate from the user equilibrium and benefit (arrive faster). The formation of such a club has negative consequences for other users, who are not invited to join it and now travel longer, and for the system, making it suboptimal and disequilibrated, which triggers adaptation dynamics. This discovery has profound implications for the future of our cities. We demonstrate that, if not prevented, CAV operators may intentionally disequilibrate traffic systems from their classic Nash equilibria, benefiting their own users and imposing costs on others. These findings suggest the possible emergence of an exclusive CAV elite, from which human-driven vehicles and non-coalition members may be excluded, potentially leading to systematically longer travel times for those outside the coalition, which would be harmful for the equity of public road networks.

翻译：用户均衡是所谓路径博弈的标准表示，在该博弈中驾驶员调整其路径选择以尽可能快地到达目的地。对于因技术和行为约束而未形成联盟的人类驾驶员而言，询问该均衡是否稳定并无意义。但对于能够通过通信协作共同形成路径联盟的互联自动驾驶车辆而言，情况已不再如此。我们首次在一个精心设计的玩具网络示例中证明了这一点：一个由三辆自动驾驶车辆组成的"俱乐部"共同决定偏离用户均衡并获益（更快到达）。此类俱乐部的形成会对其他用户产生负面影响——未被邀请加入的车辆现在行驶时间更长，同时也会损害系统最优性并破坏均衡，从而触发适应动态。这一发现对我们城市的未来具有深远影响。我们证明，若不加以预防，CAV运营商可能有意使交通系统偏离其经典纳什均衡，使其自身用户获益而将成本强加于他人。这些发现表明未来可能出现排他性的CAV精英群体，人类驾驶车辆及非联盟成员可能被排除在外，导致联盟外车辆系统性地面临更长的出行时间，这将损害公共道路网络的公平性。