As the rapid development of connected vehicles (CVs), it is inevitable that human-driven vehicles (HVs) and CVs run on a same road in the near future. Besides the traffic efficiency, the sustainable development in society cares more and more about particulate matter (PM) emissions very recently. In this work, mixed traffic flows with both CVs and HVs on a two-lane expressway are proposed and effects of CVs penetration rate on the traffic flow and the PM emission are the focus. The numerical simulation results show that the traffic flow is effectively improved as the proportion of CVs increases. But there are two stages of PM emissions. When the density is lower, the greater the proportion of CVs, the lower the PM emissions. When the density is higher, the situation reverses. Furthermore, traffic flows on two lanes are not the same and the symmetry is terribly broken when the penetration of CVs is high. As for the forward observable interval of CVs, it can limit PM emissions and increase traffic flow. Thus a high traffic efficiency and a low PM emission asks for a high CVs penetration but an appropriate observable interval.
sun et al. (Wed,) studied this question.