Service Operations for Mixed Autonomous Paradigm : Lane Design and Subsidy

This paper aims to examine and design operational strategies for mixed flows of autonomous vehicles (AVs) and human-driven vehicles (HVs). Unlike HV drivers who are heterogeneous in driving behaviors, AVs are expected to make optimal driving controls and improve mobility in platoons. Moreover, AVs make grouped travel decisions, while an HV driver only considers his/her own utility. Concerning the two major distinctions, a stylized game-theoretical model is proposed to evaluate the consequences of this mixed-autonomous paradigm. First, we consider a mixed policy where AVs and HVs share the same lane. We characterize the optimal mobility decisions for both AVs and HVs under the mixed policy and find that AVs under-join the roadway, while HVs over-join. We further identify two important effects of AVs: the platooning effect which benefits AVs throughput and user welfare and the crowding-out effect which prevents HVs' over-joining behavior. Second, we design a dedicated policy and examine the impact of opening a dedicated highway lane to AVs. The finding is that a dedicated policy alone can either improve the social welfare or aggregate throughput but not both. The insight is that government should encourage the participation of AVs if social welfare is considered an important objective. The opposite is true if the aggregate throughput is to be maximized.Third, by introducing subsidy for AVs into the dedicated model to mitigate the crowding-out effect, we find that a win-win situation where both social welfare and aggregate throughput are improved can be achieved.Finally, by considering different market penetration of AVs, we obtain a somewhat surprising result: when the market penetration of AVs is very low, a dedicated policy alone is enough to improve both social welfare and aggregate throughput. In other words, subsidy should be provided only when AVs become popular.These results together are insightful for policy-makers to arrange the development patterns of AVs: first designing dedicated lanes for AVs when they are emerging, and then providing subsidies for them when they become popular