Arterial Green-wave Band Design With Tram Priority

As a public transport system between urban rail transit and regular bus,tram has appeared in many domestic cities in recent years.At present,there are few researches on tram green wave design,which can not take into account the interests of trams and general vehicles.For example,the classic green wave models are designed for general vehicles,and they cannot generate tram green wave.Some arterial signal coordination models can generat tram green wave,but they cannot provide green wave for general vehicles.In view of the shortcomings of current research,the research contents in this paper are as follows:On the basis of improving the intersection signal timing method under the condition of tram,the MAXBAND model is used as the underlying model,and an arterial green wave model considering tram is designed.In the classical green wave model,the relevant parameters of tram green wave system are added,and the timespace graph including tram green wave system and general vehicle green wave system are drawn.With the help of time-space graph,basic constraints of two kinds of green system and interactive constrains are constructed.Under the full consideration of the traffic demand of tram,the goal of the model is to persuit the maximum general vehicle green wave bandwidth,and the tram green wave bandwidth is considered as a constraint.Due to the randomness of the stopping time of tram,the fluctuation of stopping time will result in that the tram can not reach the intersection according to the schedule.When the fluctuation is large,the tram will stop at the intersection.To avoid these situations,a strategy of active priority control for tram is proposed.Firstly,the location of tram detectors is classified,and the predicted arrival time model of tram under different classifications is proposed.Secondly,according to the signal phases when detectors detect the tram,the detection time are divided into four cases.Finally,the models of tram phase early start time,tram phase extension time and the real-time of other phases ard derived.In order to verify the feasibility of the proposed models,this paper takes the Nanjing Hexi tram as the research subject.The main parameters in the arterial green wave model and the active priority control model are calibrated through the field survey data and the reference material.Then,the signal phase sequence,timing and phase difference of each intersection are optimized by arterial green wave model.The timespace graph containing two kinds of green wave systems are drawn.With the help of VISSIM simulation software,the research subject is modeled.Under the condition of arterial green wave and active priority control,the operation situation of trams and general vehicles is evaluated.The simulation results show that the arterial green wave can effectively reduce the parking numbers and delay time of the main road straight general vehicles and trams.When trams cannot arrive at the intersection according to schedule,the active priority control ensures that trams pass the intersection successfully,but it will have a negative impact on general vehicles in other phases.