Research On Vehicle Visibility Detection And Warning Method On Foggy Day

Nowadays，the automobile has become indispensable traffic tools for the people indaily life and working. The development of automobile industry and road system providesthe necessary means and infrastructure of transportation for improving people’s quality oflife, greatly changing people’s life. However，people have to face the increasingly seriousenvironmental and traffic safety. The rate of highway traffic accident caused by weather alsoincreased year by year, and the influence of fog is particularly serious in road traffic safety.When driving in fog, the driver controls the vehicle distance and speed, according totheir perception of the fog concentration. However, the influence perception factors not onlyinclude the fog concentration, but also the fog duration. It is the need of the fog generationand dissipates for some time, the process of which cause the trouble of correctly judge thevehicle state and distance and speed. Due to the influence of fog on the vision, and visibilityconstraints of the human, so vehicle speed and safety are very low in low visibilityconditions. The safe speed judgment depends mainly on the driver’s experience, which’saccuracy and reliability is low and poor. The establishment of highway security system,provides the road weather forecast, and limits the maximum speed in fog area,advantageously reduces the part of traffic accident. When fog is produced, the accident isinevitable in case of emergency and valley fog. The visibility detection equipment，which isinstalled in the car and timely forecast safe speed, can avoid this accident. At present,visibility detection equipment is used in a fixed place, and is more expensive, can not bedirectly installed in ordinary vehicles.Therefore, the main purpose of this paper is to study the relationship between thevisibility and safety speed, the visibility detection methods, the vehicle fog visibility test,and to get the visibility value by measuring the transmittance of light in the fog spread. Thelight-emitting diode is used as a light source; a photosensitive resistance is used as aphotoelectric detector for receiving. By the calculation of the optical signals received, thevisibility value is obtained. The door structure is designed to close fog in the sampling andto shield environment light and air. This equipment is simple to use, and realizes the vehiclemoving fog detecting visibility function. Through the CFD analysis of the sample fog，study the effects of structure and the speed in collecting the sample fog. By the relationshipbetween visibility and safety speed, the people’s Republic of China Road Traffic Safety Law,calculate maximum vehicle speed and limit speed to ensure the safety of vehicle. So, thisequipment improve traffic safety level in low visibility conditions to ensure the safety andsmooth of transportation, has important economic benefit and social benefit...