A semiautomatic control system or control method ensures a driving method which is as energy-saving as possible. In the system, there is both a) manual inputting of control data, for example a definition of a vehicle speed specified value, by the driver of the vehicle and b) automatic determination of the most energy-saving vehicle speed as a function of predefined peripheral conditions, for example a general travel schedule, the topology of a route, vehicle-specific peripheral conditions and the like. An inference system determines which of these two values is smaller, and the smaller value is used to make possible safe and at the same time energy-saving travel (or journey). A safety check of the manual travel speed input value and of the automatically determined travel speed specified value can also be performed to reliably prevent a maximum permissible travel speed value from being exceeded.