scholarly journals Best-effort highway traffic congestion control via variable speed limits

2011 ◽  
Author(s):  
Carlos Canudas de Wit
Keyword(s):  
Congestion Control ◽  
Traffic Congestion ◽  
Variable Speed ◽  
Highway Traffic ◽  
Speed Limits ◽  
Best Effort ◽  
Variable Speed Limits ◽  
Traffic Congestion Control

An integrated control method based on the priority of ways in a freeway network

2016 ◽  
Vol 40 (3) ◽  
pp. 843-852 ◽  
Author(s):  
Minghui Ma ◽  
Shidong Liang
Keyword(s):  
Traffic Congestion ◽  
Control Method ◽  
Integrated Control ◽  
Adaptive Controller ◽  
Ramp Metering ◽  
Traffic Density ◽  
Variable Speed ◽  
Speed Limits ◽  
Variable Speed Limits ◽  
Freeway Networks

Traffic congestion is a common problem in merging regions of freeway networks. An adaptive integrated control method involving variable speed limits and ramp metering is presented with the aim of easing traffic congestion at merging regions. The problem of the imbalanced rights of ways of the upstream mainline and on-ramp at the merging region is solved by constructing the evaluation indices of congestion degree. Specifically, the traffic density and queue length of the upstream mainline and on-ramp are selected for use in the evaluation indices. Then, an adaptive controller is designed, integrating variable speed limits and ramp metering. The proposed method is tested in simulations considering a real freeway network in China calibrated by real traffic variables. The results show that the proposed adaptive integrated control method can prevent traffic flow breakdown and maintain a high outflow at the merging region during peak periods. The adaptive integrated control may lead to a 17% improvement in traffic delay.

scholarly journals Integrated Traffic Control for Freeways using Variable Speed Limits and Lane Change Control Actions

2019 ◽  
Vol 2673 (9) ◽  
pp. 602-613 ◽  
Author(s):  
Vasileios Markantonakis ◽  
Dimitrios Ilias Skoufoulas ◽  
Ioannis Papamichail ◽  
Markos Papageorgiou
Keyword(s):  
Control Strategy ◽  
Traffic Control ◽  
Traffic Congestion ◽  
Communication Systems ◽  
Feedforward Control ◽  
Control Strategies ◽  
Connected Vehicles ◽  
Variable Speed ◽  
Speed Limits ◽  
Variable Speed Limits

The wide deployment of vehicle automation and communication systems (VACS) in the next decade is expected to influence traffic performance on freeways. Apart from safety and comfort, one of the goals is the alleviation of traffic congestion which is a major and challenging problem for modern societies. The paper investigates the combined use of two feedback control strategies utilizing VACS at different penetration rates, aiming to maximize throughput at bottleneck locations. The first control strategy employs mainstream traffic flow control using appropriate variable speed limits as an actuator. The second control strategy delivers appropriate lane-changing actions to selected connected vehicles using a feedback-feedforward control law. Investigations of the proposed integrated scheme have been conducted using a microscopic simulation model for a hypothetical freeway featuring a lane-drop bottleneck. The results demonstrate significant improvements even for low penetration rates of connected vehicles.

scholarly journals Dynamic Analyses of Urban Expressway Network with Mesoscopic Traffic Flow Model Integrated Variable Speed Limits

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Shu-Bin Li ◽  
Bai-Bai Fu ◽  
Wen-Xiu Dang
Keyword(s):  
Traffic Flow ◽  
Traffic Congestion ◽  
Velocity Model ◽  
Variable Speed ◽  
Queuing Model ◽  
Movement Model ◽  
Speed Limits ◽  
Flow Models ◽  
Urban Expressway ◽  
Variable Speed Limits

Urban congestion is a major and costly problem in many cities both in China and other countries. The purpose of building urban expressway is to alleviate the growing traffic pressure. In this paper, the mesoscopic traffic flow models are improved by variable speed limits strategy for the dynamic of vehicles on urban expressway network. The models include static queuing model, the velocity model, and the movement model of the vehicle. Moreover the method of the simulation is also proposed. So that we can get the corresponding variable speed limits values and aid traffic managers in making decisions to develop a network traffic flow control strategy. In the end, the elevated expressway of Jinan city is used as a simulation example. We investigated the performance of the transport system with averaged density, speed, and flow on link. We also analysed the dynamic of the traffic system on expressway network at different demand levels. The simulation results show that the models are feasible and effective and the variable speed limits strategy can successfully alleviate the traffic congestion in some extent. The operational efficiency of the transportation system is greatly improved.

scholarly journals Integrated Variable Speed Limits Control and Ramp Metering for Bottleneck Regions on Freeway

2015 ◽  
Vol 2015 ◽  
pp. 1-17 ◽  
Author(s):  
Ming-hui Ma ◽  
Qing-fang Yang ◽  
Shi-dong Liang ◽  
Zhi-lin Li
Keyword(s):  
Traffic Flow ◽  
Traffic Congestion ◽  
Ramp Metering ◽  
Variable Speed ◽  
Speed Limits ◽  
Advanced Control ◽  
Variable Speed Limits ◽  
Travel Delay ◽  
Freeway Bottleneck

To enhance the efficiency of the existing freeway system and therefore to mitigate traffic congestion and related problems on the freeway mainline lane-drop bottleneck region, the advanced strategy for bottleneck control is essential. This paper proposes a method that integrates variable speed limits and ramp metering for freeway bottleneck region control to relieve the chaos in bottleneck region. To this end, based on the analyses of spatial-temporal patterns of traffic flow, a macroscopic traffic flow model is extended to describe the traffic flow operating characteristic by considering the impacts of variable speed limits in mainstream bottleneck region. In addition, to achieve the goal of balancing the priority of the vehicles on mainline and on-ramp, increasing capacity, and reducing travel delay on bottleneck region, an improved control model, as well as an advanced control strategy that integrates variable speed limits and ramp metering, is developed. The proposed method is tested in simulation for a real freeway infrastructure feed and calibrates real traffic variables. The results demonstrate that the proposed method can substantially improve the traffic flow efficiency of mainline and on-ramp and enhance the quality of traffic flow at the investigated freeway mainline bottleneck.

scholarly journals Optimal Coordination of Variable Speed Limits to Suppress Shock Waves

2003 ◽  
Vol 1852 (1) ◽  
pp. 167-174 ◽  
Author(s):  
A. Hegyi ◽  
B. De Schutter ◽  
J. Hellendoorn
Keyword(s):  
Shock Waves ◽  
Variable Speed ◽  
Highway Traffic ◽  
Speed Limits ◽  
Variable Speed Limits ◽  
Control Objective ◽  
Safety Constraints ◽  
Optimal Coordination ◽  
Safety Constraint ◽  
Discrete Controller

A model predictive control (MPC) approach is presented to optimally coordinate variable speed limits for highway traffic. A safety constraint incorporated in the controller is formulated that prevents drivers from encountering speed limit drops larger than, say, 10 km/h. The control objective is to minimize the total time that vehicles spend in the network. This approach results in dynamic speed limits that reduce or even eliminate shock waves. To predict the evolution of the traffic flows in the network, which is required by MPC, an adapted version of the METANET model is used that takes the variable speed limits into account. The performance of the discrete-valued and safety-constrained controllers is compared with the performance of the continuous-valued unconstrained controller. It is found that both types of controllers result in a network with less congestion, a higher outflow, and hence a lower total time spent for drivers. For the benchmark problem, the performance of the discrete controller with safety constraints is comparable with the continuous controller without constraints.

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