Building on the foundational concepts introduced in Chap.  1 , this chapter explores the core principles of FL and its integration with the IoT within smart mobility systems. The chapter begins by examining the different FL architectures, discussing their suitability for decentralized data processing in mobility environments. It then investigates optimization and communication strategies essential for improving FL performance in IoT networks, focusing on challenges related to resource constraints and network efficiency. Privacy and security concerns are addressed, emphasizing how FL can safeguard data privacy in mobility applications. The role of IoT and edge computing in facilitating FL is also discussed, highlighting their synergy in enabling real-time, localized processing. Finally, the chapter illustrates how the combination of FL and IoT enhances the scalability, efficiency, and security of mobility solutions, building towards a more connected and intelligent transportation system.