  Road user trajectory prediction in dynamic environments is a challenging but
crucial task for various applications, such as autonomous driving. One of the
main challenges in this domain is the multimodal nature of future trajectories
stemming from the unknown yet diverse intentions of the agents. Diffusion
models have shown to be very effective in capturing such stochasticity in
prediction tasks. However, these models involve many computationally expensive
denoising steps and sampling operations that make them a less desirable option
for real-time safety-critical applications. To this end, we present a novel
framework that leverages diffusion models for predicting future trajectories in
a computationally efficient manner. To minimize the computational bottlenecks
in iterative sampling, we employ an efficient sampling mechanism that allows us
to maximize the number of sampled trajectories for improved accuracy while
maintaining inference time in real time. Moreover, we propose a scoring
mechanism to select the most plausible trajectories by assigning relative
ranks. We show the effectiveness of our approach by conducting empirical
evaluations on common pedestrian (UCY/ETH) and autonomous driving (nuScenes)
benchmark datasets on which our model achieves state-of-the-art performance on
several subsets and metrics.
