A Risk Assessment Method for Freeway Operating Buses Based on Interval Type-2 Triangular Fuzzy Theory

In order to assess the operation risk of freeway operating buses, a method of operating risk assessment of freeway operating buses based on GPS data is proposed by using the interval type-2 triangle fuzzy theory. The frequency of continuous deceleration of operating buses, average speed and freeway horizontal and longitudinal design parameters were selected as risk assessment indexes, and operation risks were divided into four levels: safe, safer, more dangerous and hazardous. The upper and lower membership functions of the interval type-2 triangular fuzzy number were constructed by using the boundary limits of each risk level, and the corresponding interval membership matrix was constructed according to the value of the evaluation index. The index weight value was calculated by using the overrate method, and the interval membership matrix and index were weighted and summed to get the comprehensive membership interval. Finally, the membership vector of the risk level was determined by using the possibility ranking method. The risk level is evaluated according to the principle of maximum membership degree. The results show that the evaluation method has realized the quantitative and graded evaluation of the operating risk of operating buses on freeways, and identified the sections with poor safety. Taking the G12 Hui Wu Freeway from Jilin to Changchun Longjia Airport as an example, the effectiveness of the evaluation method has been verified.