||Analyzing the energy consumption for road vehicles and the corresponding driving behaviors are critical tasks for the realization of public traffic with a low energy cost and high efficiency. Especially, intelligent and connected vehicular technologies potentiate the energy-saving driving with ubiquitous and sensible traffic information. In this research, we try to utilize the advanced optimal control algorithm to optimize the driving decision and control output from vehicle powertrain so that the relationship between vehicle driving, road condition, traffic situation and powertrain efficiency can be fully matched to realize the energy-efficient driving. Meanwhile, the personalized driving styles are expected to be incorporated into the automated driving control system to quantitatively evaluate the impact from driving style on energy consumption. Ultimately, a human-oriented, safer, smarter and decarbonized energy-efficient autonomous driving system is expected to be developed for the next-generation mobility.