Optimal allocation model of signalized intersections with dynamic use of exit lanes for left turn

In order to improve the operational efficiency of heavy left-turn demand intersections,an optimal allocation model of an intersection with dynamic use of exit lanes for left turns(EFL)is proposed.The constraints of setting EFL are analyzed,including the number and length of reverse variable lanes,flow direction constraints,and signal constraints,etc.The constraints and control variables are combined in a unified framework for simultaneous optimization.The objective functions are defined as the average delay and left-turn capacity of an intersection.The model is solved by a non-dominated genetic algorithm(NSGA-Ⅱ).The results show that after the optimal allocation of EFL,the average vehicle delays of the intersection can be reduced by 14.9%and left-turn capacity can be increased by 19.3%.The effectiveness of the optimal allocation model of EFL is demonstrated.

Simulation model of self-organizing pedestrian movement considering following behavior

A new force is introduced in the social force model （SFM） for computing following behavior in pedestrian counterflow, whereby an individual tries to approach others in the same direction to avoid conflicts with pedestrians from the opposite direction. The force, like a kind of gravitation, is modeled based on the movement state and visual field of the pedestrian, and is added to the classical SFM. The modified model is presented to study the impact of following behavior on the process of lane formation, the conflict, the number of lanes formed, and the traffic efficiency in the simulations. Simulation results show that the following behavior has a significant effect on the phenomenon of lane formation and the traffic efficiency.

Optimal charging plan for electric bus considering time-of-day electricity tariff

Purpose–The purpose of this study is to develop an optimization method for charging plans with the implementation of time-of-day(TOD)electricity tariff,to reduce electricity bill.Design/methodology/approach–Two optimization models for charging plans respectively with fixed and stochastic trip travel times are developed,to minimize the electricity costs of daily operation of an electric bus.The charging time is taken as the optimization variable.The TOD electricity tariff is considered,and the energy consumption model is developed based on real operation data.An optimal charging plan provides charging times at bus idle times in operation hours during the whole day(charging time is 0 if the bus is not get charged at idle time)which ensure the regular operation of every trip served by this bus.Findings–The electricity costs of the bus route can be reduced by applying the optimal charging plans.Originality/value–This paper produces a viable option for transit agencies to reduce their operation costs.

Modeling Car-Following Dynamics During the Starting and Stopping Process Based on a Spring System Model

Car-following models describe how one vehicle follows the preceding vehicles.ln order to better model and explain car-following dynamics,this paper categorizes the state of a traveling vehicle into three sub-processes:the starting(acceleration)process,the car-folloing process,and the stopping(deceleration)process.The stating process primarily involves vehicle acceleration behavior.The stopping process involves not only car-following behavior but also deceleration behavior.This paper regards both the stopping process and the starting process as spring systems.The car-following dynamics during the starting process and the stopping process is modeled in this paper.The parameters of the proposed models,which are represented in the form of trigonometric functions,possess explicit hysical meaning and definitive ranges.We have calibrated the model of the starting process using data form the Traffic Engineering Handbook and ob-tained reasonable results.Compared with traditional stimulus-response car-following models,this model can better explain traffic flow phenomena and driver behavior thery.

Trip energy consumption estimation for electric buses

This study aims to develop a trip energy consumption(TEC)estimation model for the electric bus(EB)fleet planning,operation,and life-cycle assessment.Leveraging the vast variations of temperature in Jilin Province,China,real-world data of 31 EBs operating in 14 months were collected with temperatures fluctuating from
27.0 to 35.0℃.TEC of an EB was divided into two parts,which are the energy required by the traction and battery thermal management system,and the energy required by the air conditioner(AC)system operation,respectively.The former was regressed by a logarithmic linear model with ambient temperature,curb weight,travel distance,and trip travel time as contributing factors.The optimum working temperature and regression parameters were obtained by combining Fibonacci and Weighted Least Square.The latter was estimated by the operation time of the AC system in cooling mode or heating mode.Model evaluation and sensitivity analysis were conducted.The results show that:(i)the mean absolute percentage error(MAPE)of the proposed model is 12.108%;(ii)the estimation accuracy of the model has a probability of 99.7814% meeting the requirements of EB fleet scheduling;(iii)the MAPE has a 1.746% reduction if considering passengers’boarding and alighting.

Improving schedule adherence based on dynamic signal control and speed guidance in connected bus system

Purpose–The purpose of this paper is to develop a dynamic control method to improve bus schedule adherence under connected bus system.Design/methodology/approach–The authors developed a dynamic programming model that optimally schedules the bus operating speed at road sections and multiple signal timing plans at intersections to improve bus schedule adherence.First,the bus route was partitioned into three types of sections:stop,road and intersection.Then,transit agencies can control buses in real time based on all collected information;i.e.control bus operating speed on road sections and adjust the signal timing plans through signal controllers to improve the schedule adherence in connected bus environment.Finally,bus punctuality at the downstream stop and the saturation degree deviations of intersections were selected as the evaluation criteria in optimizing signal control plans and bus speeds jointly.Findings–An illustrative case study by using a bus rapid transit line in Jinan city was performed to verify the proposed model.It revealed that based on the proposed strategy,the objective value could be reduced by 73.7%,which indicated that the punctuality was highly improved but not to incur excessive congestion for other vehicular traffic.Originality/value–In this paper,the authors applied speed guidance and the adjustment of the signal control plans for multiple cycles in advance to improve the scheduled stability;furthermore,the proposed control strategy can reduce the effect on private traffics to the utmost extend.