Towards a Trajectory-powered Foundation Model of Mobility

This position paper advocates for the development of a geospatial foundation model based on human mobility trajectories in the built environment. Such a model would be widely applicable across many important societal domains currently addressed independently, including transportation networks, data-driven urban planning and management, tourism, and sustainability. Unlike existing large vision-language models, trained primarily on text and images, this foundation model should integrate the complex spatiotemporal and multimodal data inherent to human mobility. This paper motivates this challenging research agenda, outlining many downstream applications that would be differentially impacted or enabled by such a model. It then explains the critical spatial, temporal, and contextual factors that the model must capture to effectively analyze trajectories. Finally, it concludes with several research questions and directions, laying the foundations for future exploration in this exciting and emerging field.