It is critical for autonomous vehicles to accurately forecast the future trajectories of surrounding agents to avoid collisions. However, capturing the complex interactions between agents in complex urban scenes is challenging. As a result, complex interactions may impair trajectory prediction accuracy. A trajectory prediction network with an enhanced Graph Transformer (TP-EGT) is proposed to forecast the future trajectories of traffic-agents. A collision-aware Graph Transformer is introduced to capture the complex social interactions between traffic-agents. Following that, an additional interaction prediction task that could predict the interaction probabilities between agents is proposed to mitigate the over-smoothing issue of the Graph Transformer via a multi-task learning strategy. Afterward, the trajectory prediction performance is improved with additional interaction probabilities, which are beneficial for the decision-making and planning modules of autonomous vehicles. Quantitative and qualitative evaluations of TP-EGT on the ETH/UCY and ApolloScape databases demonstrate that the trajectory prediction accuracy of TP-EGT is comparable to the state-of-the-art baseline methods, and the predicted interaction probabilities can help autonomous vehicles comprehend the complex traffic scenes.
1 June 2020 in Physica A: Statistical Mechanics and its Applications
Connected and Autonomous Vehicles (CAVs) can receive various information from surrounding vehicles through Vehicle‐to‐Everything (V2X) communication technologies and adjust their car‐following behaviour accordingly. Although several studies have evaluated the impact of CAVs on traffic flow stability in a small segment of networks, most approaches are focused on their specific applications considering the trajectory information, and there is a lack of studies analyzing the impact of CAVs on a large‐scale network. This paper proposes a novel viscous continuum traffic model considering the anticipation of space headway, the throttle angle, and brake torque information during cooperative car‐following. The methods employed to develop the new car‐following model and its counterpart continuum traffic model have been described. The linear and non‐linear stability analyses of the newly developed model have been conducted to obtain the critical stability factors in small perturbations. Numerical simulations have been carried out to investigate the effect of the anticipation, the throttle angle, and brake torque information on traffic stability, fuel consumption, and exhaust emissions. The numerical results reveal that the anticipation of space headway and the transmission of the throttle angle and brake torque information during cooperative car‐following manoeuvres can improve the traffic flow stability and reduce fuel consumption and emissions.
2 August 2022 in Physica A: Statistical Mechanics and its Applications
In this study, a novel traffic flow modeling framework is proposed considering the impact of driving system and vehicle mechanical behavior as two different units on the traffic flow. To precisely model the behavior of Connected and Autonomous (CA) vehicles, three submodels are proposed as a novel microscopic traffic flow framework, named Integrated-Hybrid (IH) model. Focusing on the realization of the car following behavior of CA vehicles, the driving system (vehicle control system) and the vehicle mechanical system are modeled separately and linked by throttle and brake actuators model. The IH model constitutes the key part of the Full Velocity Difference (FVD) model considering the mechanical capability of vehicles and dynamic collision avoidance strategies to ensure the safety of following distance between two consecutive vehicles. Linear stability conditions are derived for each model and developing methodology for each submodel is discussed. Our simulations revealed that the IH model successfully generates velocity and acceleration profiles during car following maneuvers and throttle angle/brake information in connected vehicles environment can effectively improve traffic flow stability. The vehicles’ departure and arrival process while passing through a signal-lane with a traffic light considering the anticipation driving behavior and throttle angle/brake information of direct leading vehicle was explored. Our numerical results demonstrated that the IH model can capture the velocity fluctuations, delay times, and kinematic waves efficiently in traffic flow.