Research On Evaluation Method Of Stability For Bus Rapid Transit Running

In recent years,with the rapid development of China's economy and the acceleration of urbanization level,the urban population and the number of urban car ownerships are increasing,and the number of car trips is also gradually increasing,followed by a variety of increasingly serious urban problems,such as environmental pollution,urban traffic congestion,urban parking difficulties,residents' travel environment and livability decline.Therefore,advocating green travel and vigorously developing public transport have been important strategies for many cities to solve traffic problems and improve residents' travel environment.Bus Rapid Transit(BRT)is the main form and important part of public transport.Its form is between subway light rail and conventional bus.It has the advantages of high quality,large traffic volume,low energy consumption and low cost.However,the reality is that the service quality of BRT system in many cities in China is not high,and it can not give full play to its own advantages,making it an effective solution to solve urban traffic.Therefore,how to improve the service level of BRT quickly and effectively is the main problem faced by the rapid development of BRT.As one of the main factors that affect the service level of BRT,how to objectively evaluate and quantify BRT operation stability is very important.However,there are few special researches on this issue at home and abroad.Therefore,it is very necessary to study the quantitative index of BRT operation stability,which is also of theoretical and practical significance.On the basis of reading and analyzing a large number of domestic and foreign relevant research literatures and standards,this paper compares and analyzes the operation process of BRT operation with railway operation and car operation,which are relatively mature field,distinguishes different operation processes,considers the similarities and differences of emphases when evaluating and quantifying the stability,and clarifies the connotation of the BRT operation stability,the theoretical basis and research methods in related fields are compared and used for reference,which lays the foundation for seeking and determining the evaluation index and quantitative method of BRT operation stability.Based on the analysis of BRT operation characteristics and stability evaluation methods,this paper takes kinetic energy factor method,momentum factor method and root mean square method to characterize the operation stability of BRT.Among them,kinetic energy factor method is based on the average kinetic energy change of human body in unit distance,and momentum factor method is based on the average momentum change of human body in unit time,and the momentum factor method is to use the concept of root mean square in vibration analysis and mathematical statistics to represent the average change of acceleration.In the above three evaluation methods,the lower the evaluation value,the better the stability.Finally,Taking Jinan BRT1 line as an example,this paper takes the speed of BRT,parking information and door opening and closing records on the DVR of BRT as the basic data,and uses the kinetic energy factor method,momentum factor method and root mean square method to objectively evaluate the actual operation stability of three vehicles in 54 operation shifts in three days.Then,from the four different levels of the whole line,typical driving interval,station to station,peak and off-peak periods,analyzing the evaluation results of BRT operation stability and the accuracy and applicability of the three evaluation methods.The results show that:?when evaluating the whole line,the evaluation results of the three evaluation methods all obey the normal distribution;?from the three levels of the whole line,typical driving interval and station to station,the three evaluation methods have good consistency,and the overall evaluation results are root mean square value>kinetic energy factor>momentum factor,and the momentum factor method and root mean square value method have high consistency,besides,in some condition the kinetic energy factor method is different from the former two;?through the analysis at different levels,it is found that the difference between the kinetic energy factor method,the momentum factor method and the root mean square method is mainly affected by the time factor;?among the three methods,the kinetic energy factor method can more accurately describe the operation stability of BRT,especially in the station to station level,while the evaluation value of momentum factor method and root mean square value method will be inaccurate under some conditions due to the influence of time factor.