###### Abstract  
Currently, road transport constitutes a considerable proportion of global fossil fuel consumption, as well as CO\({}_{2}\) and pollutant emissions. To mitigate transportation energy consumption, two primary approaches have emerged: the large-scale adoption of Hybrid Electric Vehicles (HEVs) and Plug-In Electric Vehicles (PHEVs), as well as the implementation of eco-driving strategies, which present an immediate and low-cost solution. In this context, this paper provides a comprehensive review of these two technologies and their integration for connected HEV/PHEVs. We summarize the framework of recent approaches to incorporate fusion road information in single-vehicle and multi-vehicle scenarios, respectively, wherein we compare their advantages, their disadvantages, and their effectiveness in reducing energy consumption. Additionally, we reflect on the future development directions of cooperative optimization in EMS and eco-driving strategies from various perspectives. This comprehensive review underscores the importance and potential impact of these approaches in addressing environmental challenges in transportation systems, thereby offering useful insights for new researchers and practitioners in this area. c 20232013503202  
the widespread adoption of PEVs and HEVs could alleviate energy shortages, charging infrastructure limitations and range anxiety are major obstacles to their large-scale rollout, while, unlike PEVs, HEVs are formed by adding additional energy sources and storage systems, which offer a temporary solution to the above two issues under existing conditions. Therefore, they are a suitable choice during the transition period before moving to large-scale PEVs. Such a trend is also reflected in the market share performance, as Figure 1 shows. The market share of HEVs has increased significantly, capturing 3.2% of the light vehicle market in 2013 and 5.5% in 2021. PHEVs sales began in 2011, and their market share has grown every year. As of 2021, PEVs accounted for 3.2% of the light vehicle market. Consequently, the Energy Management System (EMS) of these vehicles has become an increasingly important issue. In order to better understand the following reviewed EMS solutions, Figure 2 illustrates the structural differences between the three types of Electrical Vehicles (EVs). In the case of a Hybrid Electrical Vehicle (HEV), both an engine (ICE) and an electric drive power the drivetrain. The electric motor's battery is charged by regenerative braking and a generator connected to the ICE, allowing for the use of smaller engines and improved fuel efficiency. Furthermore, for a Plug-In HEV (PHEV), the battery is charged not only by regenerative braking and the generator, but also by an external electric power source. Finally, a Pure EV (PEV) is solely powered by its battery, which is charged using an outside electric power source. Meanwhile, the second aspect focuses on improving efficiency of transportation systems and encouraging fuel-efficient driving, such as Ecological Driving (eco-driving) strategies. The concept of eco-driving involves optimizing and regulat  
Figure 1: Sales illustration of HEV/PHEV/PEV on the US market [1]. Figure 2: Basic structure of different EV types. (**a**) HEV. (**b**) PHEV. (**c**) PEV. based on various factors such as the route information and surrounding environment, which include speed limits, locations of stop signs, and Signal Phase and Timing (SPaT) information provided by Intelligent Transportation System (ITS) technology. More details, such as the use of Connected Vehicles (CVs), can lead to enhanced road safety, smoother traffic flow, and energy conservation through Vehicle-to-Vehicle (V2V) and Vehicle-to-Infrastructure (V2I) communication. V2V communication enables vehicles equipped with communication technology to exchange information, thereby preventing collisions and enabling coordinated movement.