Operating Characteristics Analysis And Safety Evaluation Of Urban Underground Road

In recent years,the level of urbanization in China has been gradually accelerating,which brings urbanization problems,such as insufficient landscape,increased traffic congestion,and serious environmental pollution.The reasonable arrangement of the urban underground road will help to change the situation.In this paper,author has finalized research methods based on the construction background and operating characteristics of urban underground road.Simulative driving and video processing technologies are used to collect characteristic parameters.The influence brought by alignment and environmental factors on vehicle speed is provided to establish the predicted model,together with the safety evaluation.Firstly,the comparative experiment is set up according to characteristics of underground road.With the method of driving simulation experiment,three typical roads are selected to analyze the difference of operating characteristics under different road conditions.The speed and offset are taken as the operation characteristic parameters for statistical analysis.Besides,the reason for the difference of operation characteristics is also analyzed,which provide a theoretical basis for guiding underground road design and safety evaluation.Secondly,the speed data is collected to further analyze the speed characteristics.Among severl acquisition methods,the road monitoring video extraction method is selected to collect vehicle speed.Based on programming software MATLAB.The steps are as follow: image and video preprocessing,moving vehicle recognition,and virtual coil speed measurement.The obtained vehicle speed data meet the requirements of this paper based on analysis.Then,the potential explanatory variables affecting the speed of the underground roads are summarized.The independent variables are defined.According to the previous research results,the speed prediction model is established at the entrance and exit of urban underground road.Finally,under the guidance of the road alignment consistency theory,the relationship between the traffic safety of the entrances and exit and the road alignment is analyzed.The technical index of alignment is constructed.The safety evaluation method and standard of alignment based on running speed are given.Based on the linear consistency theory,the safety measures of underground road are also provided.The research results and conclusions are as follow: 1.Analyze the difference in operating characteristics under different road condications through simulated driving experiments,and establish the research focus of underground roads;2.Put forward the algorithm of virtual coil method to obtain vehicle speed from surveillance video;3.Established prediction model of operating speed on entrance and exit;4.Put forward the evaluation standard of urban underground road consistency,evaluate several underground road in downtown Nanjing,and give improvement measures to road sections that do not meet the standards.This research can provide a reference for the improvement of urban underground road planning,design and operation in the future.