Traffic Control Method And Countermeasure Research Of Highway On Foggy Day

In recent years, with the rapid growth of the national freeway mileage, traffic safety has become prominent increasingly, especially in fog, the traffic safety has become a bottleneck because its constraint to the economic benefits from freeway. So, under the background that the freeway network becomes increasingly intensive and the total number of the motor vehicles is increasing, the research of methods and strategies of the freeway traffic control in fog becomes an inevitable demand and a necessary preparation. Combining the present research situation in and out for freeway traffic control in the fog, learning the advanced scientific research from the United States, Britain, Germany and the other countries, assimilating the advanced experiences in related fields, this thesis studies the issue respectively in three angles and levels of theory, technology, management. Among them, the key research is the problem of highway speed limit control in the fog.According to the Lambert-Beer's law and the formula for the relative brightness's contrast, the process of fog reducing the visibility then affecting the freeway traffic safety has been analyzed. The quantitative relationship between visibility and extinction coefficient has been given and the effect on the visibility by the microscopic amount of fog has been discussed further. Summarized the typical physical data of fog, using statistical method for the analysis of the relationship among fog visibility, fog droplet number density, water content and the other micro-amount, then obtain the regression between visibility and these amounts. Explored the influence of fog on traffic safety, analyzed the problem of the visibility to the freeway speed limit, and the highest traffic limit speed has been calculated corresponding to the different visibility conditions in the event of a heavy fog.Take examples by the research results of the relations between the fog visibility and speed on freeway, the limit speed implementation through dividing strip and minuting vehicle type on freeway, the speed choice and judgment of driver in the situation of limited speed and other problems in and out, proposed the theory of freeway dividing strip and minuting vehicle type speed limit control on foggy day. On this basis, combine with the division of speed limit interval on freeway in the United States and Germany, the research of the relation between difference of speed limit and accident rate on adjacent interval, discussed the question of the choice of the speed limit standard in the toleranced combined interval on freeway in fog.Take examples by freeway traffic management conditions on foggy day in the United States, proposed to establish the fog freeway traffic safety system of our country, which mainly including freeway weather and traffic information collection and processing system, fog freeway traffic guidance and anti-fogging system, fog freeway traffic information feedback system and fog freeway traffic accident rescue system, which can effectively prevent the generation of freeway traffic accidents in fog.In view of the existed question in freeway traffic management, proposed the traffic management improvements which mainly including twelve areas that are establish fog leveled notification system, introduce foreign advanced technology and strengthen the equipment maintenance, strengthen the construction of the streaming platform security facilities, motor vehicle driver shall comply with the provisions, establish linkage mechanism and strengthen ties, disposal the fog zone vehicle safely and effectively, adopt fog warning and speed control system, spread and diversify road weather system, increase the arrangement density of outfield equipment, develop driver decision support system, perfect linkage strategy, close freeway.