This chapter deals with the classification of automated driving functions that take effect on vehicle guidance (Donges E in ATZ/MTZ-Fachbuch. Handbuch Fahrerassistenzsysteme: Grundlagen, Komponenten und Systeme für aktive Sicherheit und Komfort, 3rd ed. vol 78, pp 15–23. Springer Vieweg, Wiesbaden, 2015). In the first step, these functions are differentiated according to their Principle of Operation (Shi et al SAE Int J Connect Autom Veh 3(1), 2020). Driving automation functions of Principle of Operation A achieve their effect on vehicle guidance by warning and informing the driver. Driving automation functions of Principle of Operation B achieve their effect on vehicle guidance by directly influencing vehicle control on a sustained basis. Driving automation functions of Principle of Operation C achieve their effect on vehicle guidance by intervening temporarily in accident-prone situations. Within a Principle of Operation, further differentiations are made. A prominent example of further differentiation is SAE Standard J3016 (SAE International/ISO in Commonwealth drive. SAE International, Warrendale, PA, United States, 2021), which subdivides the driving automation functions of Principle of Operation B further. For Principles of Operations A and C, a more detailed differentiation can be found in Shi et al (SAE Int J Connect Autom Veh 3(1,) 2020). This classification used by experts is not suitable for communicating driving automation to users. An overview of user-centered communication concepts is provided at the end of this chapter (Bundesanstalt für Straßenwesen in User communication: What does autonomous driving actually mean? 2020; Shuttleworth J in SAE Standards News: J3016 automated-driving graphic update, 2019).