Impacts of mixed autonomy traffic flow with adaptive cruise control vehicles on fuel consumption and emissions

The first generation of automated vehicles has already begun to appear on our roads in the form of adaptive cruise control (ACC). Although studies have found that ACC vehicles may theoretically improve traffic flow, recent findings show that commercially-available ACC vehicles may instead deteriorate traffic conditions. However, it is still unclear how ACC vehicles and more advanced AVs in the traffic flow will impact fuel consumption and emissions of the mixed autonomy traffic flow. To address this gap, we conduct a simulation-based study using calibrated car following models for both commercially-available ACC vehicles and theoretical automated vehicles at different market penetration rates and analyze how different market penetration rates of different automated driving systems impact traffic fuel consumption and emissions due to their impact on the emergent traffic flow dynamics. The VT-Micro model is used to estimate vehicle emissions and fuel consumption, and the results show that fuel consumption and emissions of the mixed traffic flow significantly increase at higher commercially-available ACC vehicle market penetration rates. Thus, the first generation of partial automation technologies may adversely influence traffic flow with respect to fuel consumption and emissions.