A device and a method implementable therewith for regulating the driving speed of at least one vehicle, having an electric motor/generator connected or connectable to a drive train for at least one wheel as a function of at least its actual speed and setpoint speed. The device includes a control unit for controlling the torque of the electric motor/generator, an arrangement for driving the electric motor/generator, an arrangement for recording the actual speed of the vehicle and an arrangement for preselecting the setpoint speed of the vehicle. In the device, the electric motor/generator is usable in generator operation to generate a braking torque and in engine operation to generate a driving torque.