This paper examines the impact of Cooperative Adaptive Cruise Control (CACC) on traffic flow characteristics using the traffic-flow simulation model MIXIC. CACC is an extension of Adaptive Cruise Control (ACC) that includes wireless communication between vehicles, allowing for closer following distances and tighter control. The study focuses on a highway-merging scenario from four to three lanes, analyzing the effects of CACC on traffic stability and efficiency. The results show that CACC improves traffic stability by reducing the number of shockwaves and slightly increases traffic efficiency compared to scenarios without equipped vehicles. The study also highlights the importance of CACC deployment levels and traffic conditions in determining the system's performance. The findings contribute to the understanding of CACC's potential benefits and challenges in enhancing traffic flow and safety.This paper examines the impact of Cooperative Adaptive Cruise Control (CACC) on traffic flow characteristics using the traffic-flow simulation model MIXIC. CACC is an extension of Adaptive Cruise Control (ACC) that includes wireless communication between vehicles, allowing for closer following distances and tighter control. The study focuses on a highway-merging scenario from four to three lanes, analyzing the effects of CACC on traffic stability and efficiency. The results show that CACC improves traffic stability by reducing the number of shockwaves and slightly increases traffic efficiency compared to scenarios without equipped vehicles. The study also highlights the importance of CACC deployment levels and traffic conditions in determining the system's performance. The findings contribute to the understanding of CACC's potential benefits and challenges in enhancing traffic flow and safety.