scholarly journals Variable Speed Limit and Ramp Metering for Mixed Traffic Flows: A Review and Open Questions

2021 ◽  
Vol 11 (6) ◽  
pp. 2574
Author(s):  
Filip Vrbanić ◽  
Edouard Ivanjko ◽  
Krešimir Kušić ◽  
Dino Čakija
Keyword(s):  
Traffic Control ◽  
Ramp Metering ◽  
Transport Infrastructure ◽  
Control Algorithms ◽  
Speed Limit ◽  
Mixed Traffic ◽  
Traffic Flows ◽  
Variable Speed ◽  
Variable Speed Limit ◽  
Traffic Demand

The trend of increasing traffic demand is causing congestion on existing urban roads, including urban motorways, resulting in a decrease in Level of Service (LoS) and safety, and an increase in fuel consumption. Lack of space and non-compliance with cities’ sustainable urban plans prevent the expansion of new transport infrastructure in some urban areas. To alleviate the aforementioned problems, appropriate solutions come from the domain of Intelligent Transportation Systems by implementing traffic control services. Those services include Variable Speed Limit (VSL) and Ramp Metering (RM) for urban motorways. VSL reduces the speed of incoming vehicles to a bottleneck area, and RM limits the inflow through on-ramps. In addition, with the increasing development of Autonomous Vehicles (AVs) and Connected AVs (CAVs), new opportunities for traffic control are emerging. VSL and RM can reduce traffic congestion on urban motorways, especially so in the case of mixed traffic flows where AVs and CAVs can fully comply with the control system output. Currently, there is no existing overview of control algorithms and applications for VSL and RM in mixed traffic flows. Therefore, we present a comprehensive survey of VSL and RM control algorithms including the most recent reinforcement learning-based approaches. Best practices for mixed traffic flow control are summarized and new viewpoints and future research directions are presented, including an overview of the currently open research questions.

Novel Freeway Traffic Control with Variable Speed Limit and Coordinated Ramp Metering

2011 ◽  
Vol 2229 (1) ◽  
pp. 55-65 ◽  
Author(s):  
Xiao-Yun Lu ◽  
Pravin Varaiya ◽  
Roberto Horowitz ◽  
Dongyan Su ◽  
Steven E. Shladover
Keyword(s):  
Traffic Control ◽  
Ramp Metering ◽  
Speed Limit ◽  
Variable Speed ◽  
Variable Speed Limit ◽  
Freeway Traffic

scholarly journals A Study on the Merits for Coordinated Use of Ramp Metering and Variable Speed Limit Traffic Control Systems

2018 ◽  
Vol 12 (1) ◽  
pp. 230-245
Author(s):  
Mehdi Fallah Tafti
Keyword(s):  
Control Systems ◽  
Traffic Control ◽  
Network Performance ◽  
Synergistic Effects ◽  
Ramp Metering ◽  
Speed Limit ◽  
Variable Speed ◽  
Microscopic Simulation ◽  
Variable Speed Limit ◽  
Simulated Network

Aim:The aim of this research was to investigate the merits for further improvements of traffic operation on freeways and expressways through coordinated use of Ramp Metering and Variable Speed limit (VSL) control systems.Methods:In this research, the widely used ALINEA Ramp Metering strategy was coordinated with a rule-based VSL strategy so that the total flow entered from the upstream freeway and entry ramp is maintained below the merge downstream capacity. The developed algorithm was then examined on a freeway network comprising two merge and one diverge sections, using VISSIM microscopic simulation model. The performance of the simulated network was examined under three scenarios namely, No-control, Ramp Metering only and Ramp Metering plus VSL controls. The network performance under each scenario was then assessed and compared using three measures of performance namely, average travel time, overall delay and freeway throughput. The ANOVA test was used to analyze and compare the impacts of specified scenarios.Results:The results indicated that the best performance is achieved under coordinated Ramp Metering plus VSL scenario as it produced a significantly better performance in comparison with the other two scenarios.Conclusion:The results can be attributed to the synergistic effects of coordinated and integrated use of these control systems on the freeway network and therefore, coordination of such systems is recommended.

Assessing the mobility benefits of proactive optimal variable speed limit control during recurrent and non-recurrent congestion

2015 ◽  
Vol 42 (7) ◽  
pp. 477-489 ◽  
Author(s):  
Ying Luo ◽  
M. Hadiuzzaman ◽  
Jie Fang ◽  
Tony Z. Qiu
Keyword(s):  
Traffic Control ◽  
Propagation Speed ◽  
Speed Limit ◽  
Variable Speed ◽  
Variable Speed Limit ◽  
Detection Delay ◽  
Traffic Performance ◽  
Total Travel Time ◽  
Variable Speed Limit Control ◽  
The Impact

Over the past few decades, several active traffic control methods have been proposed to improve freeway efficiency at bottleneck locations. Variable speed limit (VSL) is one of these effective controls. Previous studies have evaluated VSL control, but primarily during recurrent congestion only. This study focuses on evaluating the performance of VSL control for both recurrent and non-recurrent congestion. To assess the effectiveness of a previously proposed VSL control in a real-world situation, this study has three evaluation objectives: (1) examine the control performance when recurrent and (or) non-recurrent congestion occurs; (2) assess the effectiveness of the control when a queue encounters the VSL sign; and (3) consider the impact of system detection delay in VSL control. Comparative experiments for Whitemud Drive in Edmonton, Alberta, Canada, are simulated in the VISSIM platform, and traffic performance is compared among scenarios with and without control. The simulation results show that VSL improves mobility for both recurrent and non-recurrent congestion. The VSL control reduces total travel time, and improves total travel distance and total flow. Furthermore, it slows down the shockwave propagation speed, improves the average speed on most of the freeway segments, and reduces the duration of traffic recovery.

Simulation and Analysis of the Variable Speed Limit Controls on Highway Maintenance

2011 ◽  
Vol 97-98 ◽  
pp. 435-439 ◽  
Author(s):  
Bai Ying Shi ◽  
Xue Yu Gao ◽  
Zhi Ge ◽  
Xue Ping Ma
Keyword(s):  
Traffic Safety ◽  
Traffic Control ◽  
Simulation Software ◽  
Speed Limit ◽  
Variable Speed ◽  
Work Zones ◽  
Microscopic Simulation ◽  
Variable Speed Limit ◽  
Control Zone ◽  
Organization And Management

Despite of the fact that the traffic control zone for maintenance work (work zone) has been recognized as one of major priorities to guarantee the traffic safety, only one conventional posted speed limit (PSL) strategy is applied into the organization and management. This article presents the strategy of the variable speed limit (VSL) on highway work zones that brings about gradual deceleration and low speed variance. To evaluate the safety of the proposed VSL strategy, this study uses the microscopic simulation software VISSM to estimate the traffic flow and adopt transversal and longitudinal coefficients of safety (MSDE and cv) to compare the different speed limit strategies. The results of simulation and analysis confirm that VSL yield a substantial decrease the traffic turbulence caused by speed limit and increase the traffic safety throughout work zones.

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