Towards Synergistic Effects of C-ITS Services: Assessing the Joint Impact of GLOSA and CACC on Traffic Efficiency and Sustainability

This paper investigates the combined effects of Cooperative Adaptive Cruise Control (CACC) and Green Light Optimal Speed Advisory (GLOSA) on traffic efficiency and sustainability using microscopic traffic simulations. Addressing a gap in the literature, the research focuses on the simultaneous use of these Cooperative Intelligent Transport System (C-ITS) services rather than their individual effects. Simulations were conducted at three test sites with varying traffic characteristics and different penetration rates of C-ITS technologies. The results demonstrate that CACC significantly improves traffic flow and reduces CO ₂ emissions starting at a 16% penetration rate. However, the effects of GLOSA were marginal and statistically insignificant within the chosen simulation setup. The combined use of CACC and GLOSA provided slight improvements over CACC alone, though these differences were not statistically significant. The findings highlight the substantial benefits of CACC in enhancing traffic flow and reducing emissions, particularly at higher penetration rates. The study underscores the importance of widespread adoption of CACC and calls for further research to explore additional service combinations to optimise the potential of C-ITS for sustainable transportation.