A head up display system presents information to a human driver of a motor vehicle such that the presented information is superimposed on a windshield of the motor vehicle. An image capturing device captures an image of a scene in front of the vehicle that is representative of a background against which the information is presented to the driver. An electronic processor receives signals from the image capturing device indicative of the captured images of the scene in front of the vehicle. The processor determines, based on a color of the presented information and the signals from the image capturing device, whether the presented information is readable by the driver. If it is determined that the presented information is not readable by the driver, then a color of the presented information is changed so as to make the presented information more readable by the driver.