Improving Motorway Mobility and Environmental Performance via Vehicle Trajectory Data-Based Control

Yifei Zhao,Duo Li,Shunchao Yin,Qian Yu,Prakash Ranjitkar

doi:10.1109/access.2020.2992722

Abstract

High cost and relatively low reliability of stationary sensors hinder the wide spread of advanced motorway traffic control measures. In this research, we propose a vehicle trajectory data based variable speed limit (VSL) controller to improve mobility and environmental performance of motorways. First, a model based estimator is designed to estimate traffic states using data directly derived from probe vehicle with spacing measurement equipment (PVSMEs). Extended kalman filter (EKF) and METANET model are employed as the data assimilation tool and the process model for the estimator, respectively. Next, we incorporate the estimator with a model predictive control (MPC) to realize optimal VSL control. Finally, a 3.2km stretch in Auckland, New Zealand is selected and simulated to evaluate the proposed VSL under various PVSME penetration rates and traffic scenarios. The simulation results reveal that the PVSME-based VSL controller offers an effective solution to improve mobility and environmental performance of motorways. With an increase in PVSME penetration rates, the mobility and environmental benefits of the PVSME-based VSL increase.

Highlights

Variable speed limit (VSL) is an emerging ITS measure for motorway traffic management where the speed limit of motorway sections is determined based on real-time traffic conditions with an attempt to improve safety and harmonize the traffic flow by decreasing speed variation among vehicles across lanes, within the same lane and between upstream and downstream traffic flows
At the initial stage of probe vehicle with spacing measurement equipment (PVSMEs) deployment (1% penetration rate), the mobility gain due to the probe-based VSL was negligible; while, the probe-based VSL with 5% PVSMEs recorded an 8% improvement in Total Travel Time (TTT) compared to the no-control case
When more than 30% PVSMES were present on motorways, the proposed VSL controller witnessed around 30% reduction in TTT compared with the no-control scenario, which approached the TTT reduction produced by the stationary detector-based VSL controller

Summary

INTRODUCTION

Variable speed limit (VSL) is an emerging ITS measure for motorway traffic management where the speed limit of motorway sections is determined based on real-time traffic conditions with an attempt to improve safety and harmonize the traffic flow by decreasing speed variation among vehicles across lanes, within the same lane and between upstream and downstream traffic flows. The majority of the existing VSL systems utilize traffic measurements from the stationary sensors to determine the appropriate speed limits. In [9]–[11], the traffic state was estimated based on the trajectory data of PVSMEs. mobile data collection has begun to spread in the practical uses, a limited number of studies have investigated how probe vehicles can be used as part of a motorway control system. Han and Ahn [19] developed a breakdown probability model based on the observed headways They designed a proactive control method to reduce the breakdown probability considering connected automated vehicles (CAVs). A 3.2km stretch in Auckland, New Zealand is selected and simulated to evaluate the proposed VSL under various PVSME penetration rates and traffic scenarios

MODEL BASED TRAFFIC STATE ESTIMATOR

PROCESS MODEL

CONCLUDING REMARKS