Interactive Trajectory Prediction of Surrounding Road Users for Autonomous Driving Using Structural-LSTM Network

Accurate trajectory prediction of surrounding road users is critical to autonomous driving systems. In mixed traffic flows, road users with different kinds of behaviors and styles bring complexity to the environment, which requires considering interactions among road users when anticipating their future trajectories. This paper presents a long-term interactive trajectory prediction method for surrounding vehicles using a hierarchical multi-sequence learning network. In contrast to non-interactive method which assumes that road users are independent of each other, this method can automatically learn high-level dependencies among multiple interacting vehicles through the proposed structural-LSTM (long short-term memory) network. Specifically, structural-LSTM first assigns one LSTM for each interacting vehicle. Then these LSTMs share their cell states and hidden states with their spatial-neighboring LSTMs by a radial connection, and recurrently analyze the output state of itself as well as the other LSTMs in a deeper layer. Finally based on all output states, the network predicts trajectories for surrounding vehicles. The proposed method is evaluated on the NGSIM dataset, and its results show that satisfyingly accurate prediction performance of long-term trajectories of surrounding vehicles is accessible, e.g., longitudinal and lateral RMS error can be reduced to less than 1.93m and 0.31m over 5s time horizon, respectively.