In order to provide optimum comfort and safety conditions, information must be seen as clearly as possible by the driver and in all lighting conditions, by day and by night. Therefore, it is becoming fundamental to anticipate in order to predict what the driver will see in a vehicle, in various configurations of scene and observation conditions, so as to optimize the lighting, the ergonomics of the interfaces and the choice of surrounding materials which can be a source of reflection. This information and choices which will depend on it, make it necessary to call upon simulation techniques capable of modeling, globally and simultaneously, the entire light phenomena: surrounding lighting, display technologies, the inside lighting, taking into consideration the multiple reflections caused by the reflection of this light inside the vehicle. This has been the object of an important development, which results in the solution SPEOS Visual Ergonomics, led by company OPTIS. A unique human vision model was developed in collaboration with worldwide specialists in visual perception to transform spectral luminance information into perceived visual information. This model, based on physiological aspects, takes into account the response of the eye to light levels, to color, to contrast, and to ambient lighting, as well as to rapid changes in surrounding luminosity, in accordance with the response of the retina. This unique tool, and information now accessible, enable ergonomists and designers of on board systems to improve the conditions of global visibility, and in so doing the global perception of the environment that the driver will have.