Fuel consumption and transportation emissions evaluation of mixed traffic flow with connected automated vehicles and human-driven vehicles on expressway

Highlights: • Three car-following behaviors, namely, HDVs, ACC, and CACC are obtained. • The different models are employed to capture the car-following characteristics. • The reduction of fuel consumption and transportation emissions is investigated. • Some factors which impacted transportation emissions are discussed. The application of connected and automated vehicles can significantly reduce traffic congestion, fuel consumption, and transportation emissions. Most existing studies on connected and automated vehicles focus on improving traffic efficiency; the impact on fuel consumption and transportation emissions is not concerned. This study evaluates the influence of connected and automated vehicles on fuel consumption and emissions of mixed traffic flow on the expressway. Firstly, fuel consumption and transportation emissions models are introduced. Secondly, three car-following models are employed to capture the car-following behaviors in the mixed traffic flow. Then, a numerical simulation is designed to investigate the influence of connected and automated vehicles on fuel consumption and transportation emissions of mixed traffic flow. Finally, some factors that impacted fuel consumption and transportation emissions of mixed traffic flow are discussed. The simulation results show that connected automated vehicles can significantly reduce fuel consumption and transportation emissions. The maximum reduction percentages of HC, NOx, CO, and fuel consumption are 24.33%, 27.06%, 37.53%, and 40.58%, respectively, at 100% penetration rate of connected automated vehicles. Moreover, the parameters of the car-following models have a significant influence on fuel consumption and transportation emissions. The result indicates that the design of more minor expected headway would significantly improve the energy-saving and emissions reduction effect of connected automated vehicles.