Citation

Qin Y, Hu X, He Z, Li S. J. Air Waste Manag. Assoc. (1995) 2020; ePub(ePub): ePub.

Affiliation

School of Traffic and Transportation, Chongqing Jiaotong University, Chongqing 400074, China.

Copyright

(Copyright © 2020, Air and Waste Management Association, Publisher Informa- Taylor and Francis)

DOI

10.1080/10962247.2020.1750505

PMID

32282285

Abstract

Cooperative adaptive cruise control (CACC) vehicles need vehicle-to-vehicle (V2V) communication to achieve CACC function. When a CACC vehicle follows a manual-driven vehicle (MDV) without V2V communication, it needs degenerate to adaptive cruise control (ACC). By using real experiments, California PATH program indicated that ACC vehicles are apt to be unstable, which may have negative influence on fuel consumption and traffic emissions. Hence, this paper studies the impacts of the mixed CACC-MDV traffic on fuel consumption and emissions, by taking into consideration partial degenerations from stable CACC vehicles to unstable ACC vehicles. To deal with this, microscopic simulations were adopted by using car-following models. Then an appropriate emission model was used for evaluating the emission impacts under different CACC market penetration rates (MPRs). In order to obtain reliable evaluation results, the models validated by PATH program using real experimental data were employed as the CACC and ACC car-following models. In addition, we also analytically investigated stability of the mixed traffic flow under different CACC MPRs, in order to explore its relationship with the emission impacts. The results show that the fuel consumption and emissions firstly increase and then decrease with the increase of the CACC MPR. This means the mixed traffic under some ranges of CACC MPRs will produce more fuel consumption and emissions, compared with the full MDVs traffic. It indicates that stability situations of the mixed traffic qualitatively influence the impact trend of CACC MPRs on fuel consumption and emissions. Then V2V communication equipments on MDVs are not only encouraging, but also essential to avoid the deterioration of fuel consumption and emissions of the mixed traffic flow. Implications StatementFrom a novel perspective, emission impacts of mixed CACC-HDVs flow are studied by considering partial degeneration from stable CACC to unstable ACC. It showed that stability of the mixed traffic flow qualitatively influences the impact trend of emissions with respect to CACC market penetration rates (MPR). Full V2V communication environment is essential to reduce fuel consumption and emissions in the mixed traffic flow.

Language: en

Keywords

Traffic emissions; cooperative adaptive cruise control; fuel consumption; mixed traffic flow; stability