SCALE-Net: Scalable Vehicle Trajectory Prediction Network under Random Number of Interacting Vehicles via Edge-enhanced Graph Convolutional Neural Network

Predicting the future trajectory of surrounding vehicles in a randomly varying traffic level is one of the most challenging problems in developing an autonomous vehicle. Since there is no pre-defined number of interacting vehicles participated in, the prediction network has to be scalable with respect to the number of vehicles in order to guarantee consistent performance in terms of both accuracy and computational load. In this paper, the first fully scalable trajectory prediction network, SCALE-Net, is proposed that can ensure both high prediction performance while keeping the computational load low regardless of the number of surrounding vehicles. The SCALE-Net employs the Edge-enhanced Graph Convolutional Neural Network (EGCN) for the inter-vehicular interaction embedding network. Since the proposed EGCN is inherently scalable with respect to the graph node (an agent in this study), the model can be operated independently from the total number of vehicles considered. We evaluated the scalability of the SCALE-Net on the publically available NGSIM datasets by comparing variations on computation time and prediction accuracy per single driving scene with respect to the varying vehicle number. The experimental test shows that both computation time and prediction performance of the SCALE-Net consistently outperform those of previous models regardless of the level of traffic complexities.

I. Introduction

When implementing autonomous vehicles on real-world public roads, an autonomous vehicle must be able to cope with various driving conditions from highway to complex urban roads. For instance, the number of surrounding vehicles can vary substantially depending on the traffic levels. Under these dynamic environments, the autonomous driving algorithms have to be scalable. Unlike other parts of the autonomous driving algorithm, the prediction algorithm poses an interesting and challenging scalability problem because the number of surrounding vehicles can vary substantially.