In this paper, we investigate the impact of connected and automated vehicles (CAVs) on traffic flow at merging roadways and develop a microscopic simulation framework to explore the implications on fuel consumption and travel time. In this framework, we use optimal control to simulate the behavior of CAVs and the Gipps car following model to capture the behavior of human-driven vehicles. The simulation results show that CAVs can contribute to significant fuel consumption and travel time reduction for diverse traffic conditions under average and high congestion scenarios. Furthermore, we show that CAVs allow for more stable traffic patterns even for high density traffic.