A door system for a public transit vehicle with at least one door opening and a door that closes this door opening includes a sensor unit, which does three-dimensional and touch-free scanning of a passenger compartment in the area of the door opening and at least one communication element for the context-based communication with passengers based on readings by the sensor unit. A process for monitoring and controlling door systems of a public transit vehicle are also provided including the steps of touch-free and three-dimensional scanning of a passenger compartment in the area of a door opening with a sensor unit and measuring distances, shapes, and movements of objects by evaluating the readings of the touch-free and three-dimensional scanning. The process also includes issuing context-based information to affected passengers via a communications system, whereby the information is based on readings from the sensor unit.A process for monitoring and controlling such a door system.