In intelligent transportation systems, vehicles can obtain more information, and the interactivity between vehicles can be improved. Therefore, it is necessary to study car-following behavior during the introduction of intelligent traffic information technology. To study the impacts of drivers' characteristics on the dynamic characteristics of car-following behavior in a vehicle-to-vehicle (V2V) communication environment, we first analyzed the relationship between drivers' characteristics and the following car's optimal velocity using vehicle trajectory data via the grey relational analysis method and then presented a new optimal velocity function (OVF). The boundary conditions of the new OVF were analyzed theoretically, and the results showed that the new OVF can better describe drivers' characteristics than the traditional OVF. Subsequently, we proposed an extended car-following model by combining V2V communication based on the new OVF and previous car-following models. Finally, numerical simulations were carried out to explore the effect of drivers' characteristics on car-following behavior and fuel economy of vehicles, and the results indicated that the proposed model can improve vehicles' mobility, safety, fuel consumption, and emissions in different traffic scenarios. In conclusion, the performance of traffic flow was improved by taking drivers' characteristics into account under the V2V communication situation for car-following theory.Sustainability 2020, 12, 1552 2 of 18 by Nagel and Schreckenberg [7]. Since then, different scholars have used the cellular automata model to explore traffic phase transitions, spatiotemporal patterns of traffic flow, and mixed traffic flow (i.e., mixed bicycle traffic flow) [8][9][10]. Additionally, because the car-following model can describe complex traffic phenomena from the micro perspective, it has attracted considerable attention from scholars. Jiang et al. [11] studied the relationship between the vehicle speed and space headway under various traffic conditions using car-following experimental data and proposed a car-following model based on the following mechanism. Zhao et al. [12] explored the car-following behavior of automated vehicles on the basis of an accelerated evaluation method, and the simulation results showed that the proposed method can reduce the evaluation time of crashes, injuries, or conflict events. Fu et al. [13] proposed a human-like car-following model for autonomous vehicles and connected vehicles. In addition, Tian et al. [14] proposed a new car-following model based on the revised Intelligent Driver Model [15] and explored the effect of speed adaptation and spacing indifference on traffic instability. In summary, the car-following model can describe complex microscopic traffic flow phenomena such as traffic congestion, stop-and-go waves, and traffic phase transitions. Therefore, systematic research on modeling car-following behavior has been rapidly developed.However, there are few studies on the impact of drivers' characteristics on the car-f...