Research On Operating Characteristics And Optimization Technique Of BRT

In recent years,BRT develops fast in China.There are nearly 30 cities built BRT,and there are more cities plans to construct BRT system.Rapid construction brings some problems such as blindness and not scientific in planning and design.There is a late start of BRT in China,and relevant theoretical research should be continuing improvement.More suitable theory and practice should be used in the constrictions of BRT in ChinaThis paper analyzes the characteristics such as speed,distribution of passengers,distributions of arrival time and dwell time based on the theory and practice of studies of BRT.Then,capacity models of single loading area and double loading areas are established based on LOS.BRT signal priority method and theory based on grade are put forward,and the method about marshalling operation mode is analyzed.The research results of the paper can be used to support operation and management of BRT.First,spatial distribution model of passengers at bus stop is established.The phenomenon of passengers usually waiting for BRT vehicles at one loading area is found by traffic survey.So the inhomogeneity of distribution of passengers at BRT station is more obvious than metro platform.Four influencing factors such as space in BRT vehicle,walking distance,and waiting time are proposed as the main factors for passengers' distribution.And the passengers' distribution model is established based on these four factors to describe the inhomogeneity phenomenon.Second,dwell time model of BRT vehicle based on passengers in BRT vehicle is established.The influence of density in BRT is analyzed to illustrate the retardant effect of efficiency boarding and alighting.And dwell time model is established based on parameters of the number of passengers boarding and alighting,and loading coefficient.Third,the paper points out in that long red time is the main factor caused queue and large interval.Statistic test points out that the distribution of arrival frequency is accord with Poisson distribution,and the distribution of dwell time is accord with the Irish distribution.The conclusion is that once the queue and large interval occurred,the situation of queue and large interval will become more serious.And the probability of queue and queue length are calculated to define reasonable departure frequency.Fourth,capacity model of BRT based on LOS is established.Capacity modeling method from highway capacity manual and transit capacity and quality of service manual and Queuing Theory are analyzed.Then,the capacity model of single loading area of Mid-Block setting mode is established based on parameters of signal time,queue time and service intensity,and the capacity models of normal departure mode and marshalling operation mode are established.At last,influence factors for capacity of Near-Side and Far-Side setting mode BRT station are analyzed,and the capacity model of single loading area is established.Fifth,real time signal priority technique and method of BRT is studied.The disadvantage that all of the BRT vehicles getting to intersections will have priority in the past is analyzed.And,signal priority model is established based on indexes such as on time,headway with vehicle at front,headway with vehicle at behind and the number of passengers in BRT.The implement method is proposed by using grade of saturability.Real time signal priority method is used to solve the problem in implement of green signal ahead of schedule.And calculation method based on real time passengers volume and location technique is proposed to better forecast BRT vehicles getting to stations and intersections.Sixth,applicability and advantage of marshalling operation mode is analyzed focus on the deterioration of LOS high departure rate and the situation of the serious imbalances for using efficiency of loading areas.It is pointed out that there are advantages such as uniform spatial distribution of passengers in bus stop,promotion of passengers' capacity and vehicle speed of marshalling operation mode.And marshalling operation mode is beneficial to enhance stability of BRT system.At last,BRT1 in Jinan city is used as case to analyze the efficiency and implementation effect of BRT signal priority.The results indicate that this method of priority is useful to promote speed and punctuality.