Expressway Congestion State Assessment Due to Different Vehicle Types Based on Big Data
For the limitation that the unified static road congestion state assessment and control method for all vehicles are not refined,this paper focuses on the traffic flow of different types of vehicles.First,based on the gantry data of Fujian section of Shenyang-Haikou expressway,the traffic congestion characteristics of different types of vehicles with different indicators were analyzed by using clustering method.Second,the data-driven fuzzy cloud model based on different vehicle types was established to calculate the affiliation degree of congestion levels according to the numerical characteristics given by experts.Then,the congestion indicators were selected as the input of fuzzy logic system,and the Mamdani method was used to establish the fuzzy correlation matrix to quantify the credibility of different experts'evaluation.Subsequently,the Dempster-Shafter evidence theory was introduced to fuzzy fuse the comprehensive credibility of all experts.The road traffic state was judged comprehensively according to the maximum affiliation principle.Finally,the model precision and the accuracy of representation on differences among vehicle types were verified.The consistency of congestion evaluation results based on different vehicle types reached 84.51％.The result indicates that compared with 1-4 types of passenger cars and mini trucks,the bottlenecks formed by large trucks during movement exhibit a significant hysteresis effect on the expressway congestion dissipation.Under low density,the influence of penetration rate increasing of passenger cars,less-axle trucks and multi-axle trucks on road conditions is sequentially enhanced.Under high density,the penetration rate variations of 3-6 axle trucks have the most obvious influence on congestion state,followed by 1-4 axle passenger cars.The study on congestion based on different vehicle types can provide quantitative data support for active traffic management of various types of vehicles,especially has important guiding significance in dynamic regulation measures,e.g.,staggered travel and variable speed limits.
NETL
NSTL
万方数据
