Effectiveness Evaluation Of Warning Measures On Freeway Under Foggy Weather

There are a serious of traffic safety problems on freeway under foggy weather. The relevant departments and scholars have proposed a lot of disposal measures, however, few studies evaluating the effectiveness of the measures. The thesis carries out analysis of the measures effectiveness which include variable message signs and fog lamps. Establishing freeway scene by driving simulator and combining with eye tracking, this paper analyses traffic safety assessment and driver behavior by warning measures on freeway under foggy weather. The research result is beneficial to the relevant managers to improve traffic safety of freeway. The thesis is specified in the following aspects.Firstly, based on a traffic investigation on the Beijing-Zhuhai freeway and Changsha Belt freeway under foggy weather, this paper concludes the traffic characteristics through the data of speed and headway.Secondly, building the basic road model in 3Dmax and freeway scene in driving simulator, the freeway scene includes roads and driving scenarios, from variable message signs and fog lamps, and combinations of measures scene, loading 50m, 250m,500m of fog visibility environment. In order to collect driving behavior and eye movement data, a driving simulation experiment is done in this paper. The experimenters in study meet all study qualifications and with SMI iView XTM HED eye tracking instrument when they do this experiment.Then, studying assessment and prediction of traffic on freeway under foggy weather. The paper takes the method of optimal partition of Fisher, selects the visibility and headway as the indicators, to determine the risk can be divided into 4 levels and combine with loss of size to make sure the risk classification standard; Using the ordered Logistic regression to predict the risk of driving, through the visibility and the headway values to calculate the probability of risk level.Finally, this thesis from traffic risk and driving behavior to evaluate effectiveness of measures. It found that the traffic risk to most drivers are reduced after take measures; Using descriptive statistics, variance analysis, Logistic regression to analysis data at different test points, the results are followed:compared with normal weather, vehicle average speed has decreased to varying degrees when the freeway without measures. At test point where set variable message signs, according to the visibility and average speed by Logistic regression to establish the deceleration probability model, after setting the fog lamps,83.3% of the vehicles which steady speed have varying degrees of increase than no fog lamps.