A foreground extracting section extracts the foreground of each of the first to the N-th frames, and a foreground-accumulated-image configuration section configures a front accumulated image obtained by overlapping the foregrounds of the first to the N-th frames viewed from the future side and a rear accumulated image obtained by overlapping them viewed from the past side. One flywheel is mounted on the output element of the engine and another flywheel is connectable to the power train by a friction clutch. Subsequently, circuitry acts to conditionally cause a changeable road sign to display the medical condition, and conditionally transmit a radio warning signal to a vehicle, the radio warning signal indicating the medical condition. By way of example, a programmable circuit element receives velocity information on previous key strikes for adjusting the actuator velocity output signal which will be generated for future key strikes.