Recent breakthroughs in autonomy, electrification, and shared mobility are transforming transportation by opening new avenues for integrated, multi-modal transit systems with potential to benefit society as a whole. This five-day Dagstuhl Seminar aims to bring together experts from computer science, operations research, engineering, social sciences, and public policy to tackle both the theoretical and practical challenges at the intersection of data-driven transit planning, algorithm design, and real-world implementation.