Simulation of Road Capacity Considering the Influence of Buses

Jinxing Shen,Feng Qiu,Changjiang Zheng,Junjie Qi

doi:10.1109/access.2019.2942524

Jinxing Shen, Feng Qiu + Show 2 more

Open Access

https://doi.org/10.1109/access.2019.2942524

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Abstract

The traditional cellular automata model cannot fully demonstrate the effect of buses on road capacity due to the incapable of considering the difference in dynamic performance and driving behaviors between buses and other vehicles. In this paper, a novel cellular automata model accounting for car-following and lane-changing behaviors was developed to investigate the relationship between the multilane road capacity and the proportion of buses. The parameters of the model were calibrated and verified using the data collected from a real-word road with heterogeneous traffic flow. The calibration result indicates that the proposed model can accurately describe the evolution of traffic dynamics on multilane roads. It is found that drivers have a specific preference in determining the target lane in the lane-changing process. Under the same conditions, bus drivers prefer to choose the side lane of the road, while drivers of other vehicles prefer to select the middle lanes. Besides, the preference for the target lanes affects the lane-changing behaviors of the drivers, resulting in a considerable difference in optimal traffic density and maximum traffic volume in different lanes. Moreover, the simulation result suggests that the proportion of buses has a significant impact on road capacity (e.g., the capacity is reduced by as much as 18%). To increase road capacity and improve bus services, based on the proposed model, transit authorities can dynamically allocate the limited road space to buses and other vehicles according to the proportion of buses.

Highlights

Road capacity can be derived from the correlations between three key traffic variables, namely, flow, speed, and density [1]
The traffic flow containing both buses and cars was converted into an equivalent flow of cars, denoted as passenger car equivalents (PCE)
The analysis results show that the impact of buses on multilane road capacity cannot be fully characterized by a fixed PCE of buses With the changes in the proportion of buses, the road capacity varied by 18% from the peak value of 5,880 pcu/h to the minimum value of 4,859 pcu/h

Summary

INTRODUCTION

Road capacity can be derived from the correlations between three key traffic variables, namely, flow, speed, and density [1]. Chen et al estimated the capacity of urban expressway through microscale simulation [19] He and Jia et al combined the empirical data with traffic flow theory, and successfully simulated road capacity [20]–[22]. With the help of the model, we could effectively allocate limited road space to buses and other vehicles, and provide reliable public transit service while increasing the maximum traffic volume. The remainder of this paper is organized as follows: Section 2 develops a multilane cell transmission model that simulates the driving behaviors of various vehicles on multilane roads; Section 3 calibrates the variables of the established model with field data; Section 4 carries out simulations under different compositions of traffic flow; Section 5 puts forward the research conclusions

MODEL FORMULATION

POSITION UPDATE UNDER CAR-FOLLOWING STATE

POSITION UPDATE UNDER LANE-CHANGING STATE

BCALIBRATION OF LANE-CHANGING VARIABLES

SIMUALTION AND RESULTS ANALYSIS

CONCLUSION