This is an open access book. It gathers the proceedings of the 11th edition of Transport Research Arena (TRA 2026) conference, held on May 18-21, 2026, in Budapest, Hungary. The contributions cover a wide range of research findings, methodological aspects, innovative technologies, and policy implications that are currently reshaping the transportation system in Europe. Bridging academic research, industrial developments, and policy regulations, this volume offers a comprehensive review of the state-of-the-art in transportation, with a special emphasis on strategies and technologies to assess and improve pedestrian and driver safety, and to foster automated and reliable transport monitoring, and on policies to develop sustainable mobility in the city of the future.  This is the first volume of a 6-volume set.