In order to display driving assistance images to a driver in a vehicle, visible light images are captured using a visible light camera mounted for viewing a roadway on which the vehicle travels and infrared images overlapping with the visible light images are captured using an infrared camera mounted for viewing the roadway. The visible light images are normally displayed on a display screen when a visible light brightness around the vehicle is greater than a brightness threshold. Trigger conditions are monitored which are indicative of limitations of a driver visibility when directly viewing the roadway. The trigger conditions include a driver reaction. The monitored trigger condition is classified according to a plurality of predetermined classifications which indicate an occurrence of an impairment event. The infrared images are selected for display on the display screen upon occurrence of the impairment event.