Disaster Condition Of Freeway Traffic Safety Assessment Theory And Menthod Researth

Now the freeway accidents caused by atrocious weather, traffic incident etc are common.Traffic safety assessment under disaster conditions is part of traffic safety managementsystem and an accurate judgment of traffic safety level.And then proactive measures are takento prevent or reduce traffic accidents. But there are still some problems in domestic trafficsafety assessment. Based on this background，this paper makes a research about freewaytraffic safety assessment under disaster conditions in order to improve traffic safety levelmaximize.Study on formation mechanism of disaster conditions and the underlying data collectionfor its safety assessment. In this part, the type of disaster is defined which contain snow andice, rain, fog, strong wind and traffic incident, and what impacts and formation mechanismfrom disaster conditions to driving safety is analyzed on road, driver, driving environment etc,through which provide a theoretical basis for the indicators of traffic safety assessment andgiven the layout method of calculation of the basic data acquisition and equipment testing inthe safety assessment indicators.Assess the freeway traffic safety under snow and ice and rain conditions. Hereapplicates ADAMS/Car to simulate the vehicle moving in the snow and ice, rainfallconditions, with different speed in the curved sections. Under the snow and ice, short-termheavy rainfall condition, the difference of the lateral displacement of the vehicle underdisaster conditions and under normal conditions is the security evaluation index, the drivingsafety is divided in to different grades according to the simulation results. In case of heavyrainfall, the paper not only takes the difference of lateral displacement of the vehicle asdriving safety assessment indicators but takes the impact from visibility into account. Inaddition, here use difference of braking distance of the vehicles as another traffic safetyevaluation index through the comparison between the braking distance and and visibilityvalue under heavy rainfall conditions. Above two evaluation indicators’ simulation results,thispaper divide driving safety into different grades.Assess the freeway traffic safety under fog and strong wind conditions. ANFIS (adaptivefuzzy neural network) rear-end probability model is used, combined with the visibility,vehicle speed difference between the former and the after, the following vehicle’s speed, thispaper uses MATLAB programming to calculate the rear-end probability of different drivingspace in fog and divide traffic safety into grades according to the rear-end probability; What’smore,the paper uses ANSYS to simulate the vehicles’ running conditions in freeway under windy conditions, and make driving safety classification according to the vehicle lateraldisplacement through imposing different lateral surface loads on the vehicle.Assess the freeway traffic safety under traffic incidents. Combined with cellularautomaton simulated traffic flow state in the proportion of different carts and saturation usingMATLAB mathematical software under traffic incidents, recorded the number of trafficconflict and speed standard deviation between adjacent sections and lane as the safetyevaluation index, divided traffic safety rating based on the simulation results.