from the gas pedal position sensor 60 and a speed signal the output signal from the gas pedal position sensor 60 can be described as a driver 39 s choice signal which indicates the choice of the driver it is particularly advantageous when a substitute speed sensor 70 is used in place of the speed sensor 95 this is particularly important when the speed sensor 95 is defective to make available a substitute speed signal the dynamo is preferably drawn upon a signal which is proportional to the rotational speed can be measured at the dynamo thus the dynamo 70 supplies a signal which characterizes the rotational speed of the internal combustion engine thus only signals which do not require any additional sensors are processed since only very few elements such as the gas pedal sensor the substitute speed sensor and the controlling unit must be operative an emergency driving operation is possible when all remaining components fail other sensors as well can be used quite advantageously an example of such a substitute speed sensor is the start of injection sensor the appropriate sensor needs only to fulfill the condition of emitting a signal that is dependent on the rotational speed of the internal combustion engine on the basis of the speed signal the emergency controlling device 40 calculates a substitute actuating signal for the controlling unit 30 in addition to the rotational speed the gas pedal position is also considered the emergency controlling device 40 preferably has.