Placement of dedicated lanes for autonomous vehicles considering the changes of urban spatial structure

This paper investigates the placement schemes of dedicated lanes for autonomous vehicles (AVs) considering the changes of urban spatial structure in a closed city, where AVs and regular vehicles (RVs) coexist. An urban spatial equilibrium model for a monocentric and circular city is formulated, in which the travel and residential location choice are interdependent, considering the variable road capacity and reduced value of travel time brought by AVs. The theoretical boundary for the AV proportion in flow with the positive and negative influence of dedicated AV lanes on traffic efficiency are given. Then, the optimized placement of dedicated lanes for AVs, with and without consideration of residential relocation, are examined. First, the short-term effects of a dedicated AV lane are examined under a fixed residential distribution, with the objective of minimizing total travel time. The results indicate that a dedicated AV lane improves traffic efficiency only when the market penetration rate (MPR) of AVs is at a moderate level. Second, the long-term effects of a dedicated AV lane are considered, allowing for changes in residential location choices. In this case, the design objective is to maximize social welfare, and the optimal solution requires a shorter dedicated AV lane compared to the short-term scenario. The findings reveal the opposite spatial changes, that is, dedicated AV lanes encourage AV users to relocate farther from the city center, while RV users tend to move closer. Furthermore, neglecting the long-term relocation behavior of residents leads to inaccurate travel time estimates and excessive infrastructure investments.