System for visibility distance estimation in fog conditions based on light sources and visual acuity

The latest researches, according to National Highway Traffic Safety Administration, reinforce the idea that most of the accidents are not caused by car failures, the driver behavior proved to be more harmful [13]. Driving too fast for the weather conditions can cause a catastrophe. In order to improve the driver's visibility the automotive companies developed headlights based on LED or Laser devices which increase the directivity, the power and the efficiency of the beam. In this paper we present some principles which can lead to the development of a system able to estimate the visibility distance in foggy weather conditions using the light scattering property. In case of bad weather conditions, the system has to notify the drivers and to recommend a speed which ensures traffic safety. To be sure that the visibility estimation is really valid for a human being we tested the human visual system in different fog conditions using an eye chart. Measuring the visual acuity we realized a link between human and automated visibility.