In this paper, we design a safe and efficient cruise control for the connected automated vehicle with access to motion information from multiple vehicles ahead via vehicle-to-vehicle (V2V) communication. Position and velocity data collected from a chain of human-driven vehicles are systematically leveraged to design a connected cruise controller that smoothly responds to traffic perturbations while maximizing energy efficiency. A safety filter derived from a control barrier function provides the safety guarantee. We investigate the proposed control design's energy performance against real traffic datasets and quantify the safety filter's energy impact. It is shown that optimally utilizing V2V connectivity reduces energy consumption by more than 10\% compared to standard non-connected adaptive cruise control. Meanwhile, interesting interplays between safety filter and energy efficiency design are highlighted, revealing future research directions.