scholarly journals Optimization Model and Method of Variable Speed Limit for Urban Expressway

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Shubin Li ◽  
Tao Wang ◽  
Hualing Ren ◽  
Baiying Shi ◽  
Xiangke Kong
Keyword(s):  
Traffic Flow ◽  
Traffic Safety ◽  
Control Method ◽  
Flow Simulation ◽  
Urban Traffic ◽  
Speed Limit ◽  
Variable Speed ◽  
Variable Speed Limit ◽  
Urban Expressway ◽  
Proposed Model

The urban expressway network is the main part of the urban traffic network carrying most of the city’s traffic pressure for its continuity and rapidity, but the control method of the traffic flow was too simple to other control methods in application in addition to the ramp control and the fixed speed control. In this paper, the theory of variable speed limit (VSL) was used to develop an optimal control model based on the improved traffic flow simulation model according to the characteristics of urban expressway traffic flow. The objective of the proposed model is to minimize the delay and maximize the traffic flow. It can adjust the traffic flow on the network in space time so that the whole network is in a state of equilibrium which not only is conducive to the control of the local traffic congestion and avoids the spread of congestion but also improves the traffic safety. The SPSA-based solution algorithm was proposed by taking into account the needs of real-time online applications. It can not only ensure the accuracy of the solution but also meet the requirements of the simulation time. The simulation results show that the variable speed limit can be optimized in moderate demand, and the proposed model and algorithm are effective and feasible in this paper. The conclusions are useful to help the traffic management department to formulate reasonable traffic control strategies.

Variable speed limit strategies analysis with link transmission model on urban expressway

2018 ◽  
Vol 32 (06) ◽  
pp. 1850077 ◽  
Author(s):  
Shubin Li ◽  
Danni Cao
Keyword(s):  
Traffic Safety ◽  
Traffic Congestion ◽  
Management Strategies ◽  
Simulation Method ◽  
Average Density ◽  
Transmission Model ◽  
Speed Limit ◽  
Variable Speed ◽  
Variable Speed Limit ◽  
Urban Expressway

The variable speed limit (VSL) is a kind of active traffic management method. Most of the strategies are used in the expressway traffic flow control in order to ensure traffic safety. However, the urban expressway system is the main artery, carrying most traffic pressure. It has similar traffic characteristics with the expressways between cities. In this paper, the improved link transmission model (LTM) combined with VSL strategies is proposed, based on the urban expressway network. The model can simulate the movement of the vehicles and the shock wave, and well balance the relationship between the amount of calculation and accuracy. Furthermore, the optimal VSL strategy can be proposed based on the simulation method. It can provide management strategies for managers. Finally, a simple example is given to illustrate the model and method. The selected indexes are the average density, the average speed and the average flow on the traffic network in the simulation. The simulation results show that the proposed model and method are feasible. The VSL strategy can effectively alleviate traffic congestion in some cases, and greatly promote the efficiency of the transportation system.

scholarly journals Enhancing Freeway Safety through Intervening in Traffic Flow Dynamics Based on Variable Speed Limit Control

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Jinming You ◽  
Shouen Fang ◽  
Lanfang Zhang ◽  
John Taplin ◽  
Jingqiu Guo
Keyword(s):  
Real Time ◽  
Traffic Flow ◽  
New Technologies ◽  
Flow Dynamics ◽  
Crash Risk ◽  
Speed Limit ◽  
Variable Speed ◽  
Variable Speed Limit ◽  
Traffic Conditions ◽  
Safety Research

New technologies and traffic data sources provide great potential to extend advanced strategies in freeway safety research. The High Definition Monitoring System (HDMS) data contribute comprehensive and precise individual vehicle information. This paper proposes an innovative Variable Speed Limit (VSL) based approach to manage crash risks by intervening in traffic flow dynamics on freeways using HDMS data. We first conducted an empirical analysis on real-time crash risk estimation using a binary logistic regression model. Then, intensive microscopic simulations based on AIMSUN were carried out to explore the effects of various intervention strategies with respect to a 3-lane freeway stretch in China. Different speed limits with distinct compliance rates under specified traffic conditions have been simulated. By taking into account the trade-off between safety benefits and delay in travel time, the speed limit strategies were optimized under various traffic conditions and the model with gradient feedback produces more satisfactory performance in controlling real-time crash risks. Last, the results were integrated into lane management strategies. This research can provide new ideas and methods to reveal the freeway crash risk evolution and active traffic management.

scholarly journals Predicting Traffic Dynamics with Driver Response Model for Proactive Variable Speed Limit Control Algorithm

2018 ◽  
Vol 2018 ◽  
pp. 1-10
Author(s):  
Huixuan Ye ◽  
Lili Tu ◽  
Jie Fang
Keyword(s):  
Real Time ◽  
Traffic Flow ◽  
Control Algorithm ◽  
Field Data ◽  
Speed Limit ◽  
Response Model ◽  
Variable Speed ◽  
Variable Speed Limit ◽  
Driver Response ◽  
Traffic State

Variable Speed Limit (VSL) control contributes to potential crash risk reduction by suggesting a suitable dynamic speed limit to achieve more stable and uniform traffic flow. In recent studies, researchers adopted macroscopic traffic flow models and perform prediction-based optimal VSL control. The response of drivers to the advised VSL is one of the most critical parameters in VSL-controlled speed dynamics modeling, which significantly affects the accuracy of traffic state prediction as well as the control reliability and performance. Nevertheless, the variations of driver responses were not explicitly modeled. Thus, in this research, the authors proposed a dynamic driver response model to formulate how the drivers respond to the advised VSL during various traffic conditions. The model was established and calibrated using field data to quantitatively analyze the dynamics of drivers’ desired speed regarding the advised VSL and current traffic state variables. A proactive VSL control algorithm incorporating the established driver response model was designed and implemented in field-data-based simulation study. The design proactive control algorithm modifies VSL in real-time according to the traffic state prediction results, aiming to reduce potential crash risks over the experiment site. By taking into account the real-time driver response variations, the VSL-controlled traffic state dynamics was more accurately predicted. The experimental results illustrated that the proposed control algorithm effectively reduces the crash probabilities in the traffic network.

scholarly journals Evaluation of Integrated Variable Speed Limit and Lane Change Control for Highway Traffic Flow

2021 ◽  
Vol 54 (2) ◽  
pp. 107-113
Author(s):  
Tianchen Yuan ◽  
Faisal Alasiri ◽  
Yihang Zhang ◽  
Petros A. Ioannou
Keyword(s):  
Traffic Flow ◽  
Speed Limit ◽  
Lane Change ◽  
Variable Speed ◽  
Highway Traffic ◽  
Variable Speed Limit

Variable speed limit strategies analysis with mesoscopic traffic flow model based on complex networks

2018 ◽  
Vol 29 (02) ◽  
pp. 1850014 ◽  
Author(s):  
Shu-Bin Li ◽  
Dan-Ni Cao ◽  
Wen-Xiu Dang ◽  
Lin Zhang
Keyword(s):  
Complex Networks ◽  
Traffic Flow ◽  
Traffic Management ◽  
Flow Model ◽  
Complexity Science ◽  
Control Measures ◽  
Speed Limit ◽  
Variable Speed ◽  
Variable Speed Limit ◽  
Traffic Flow Model

As a new cross-discipline, the complexity science has penetrated into every field of economy and society. With the arrival of big data, the research of the complexity science has reached its summit again. In recent years, it offers a new perspective for traffic control by using complex networks theory. The interaction course of various kinds of information in traffic system forms a huge complex system. A new mesoscopic traffic flow model is improved with variable speed limit (VSL), and the simulation process is designed, which is based on the complex networks theory combined with the proposed model. This paper studies effect of VSL on the dynamic traffic flow, and then analyzes the optimal control strategy of VSL in different network topologies. The conclusion of this research is meaningful to put forward some reasonable transportation plan and develop effective traffic management and control measures to help the department of traffic management.

scholarly journals Traffic Flow Modeling of Freeway Variable Speed Limit Control Based on the Big Data of Driving Behavior

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Xu Qu ◽  
Linheng Li ◽  
Ziwei Yi ◽  
Peipei Mao ◽  
Mofeng Yang
Keyword(s):  
Cellular Automaton ◽  
Traffic Flow ◽  
Flow Characteristics ◽  
Driving Behavior ◽  
Cellular Automaton Model ◽  
Speed Limit ◽  
Variable Speed ◽  
Variable Speed Limit ◽  
Flow Models ◽  
Variable Speed Limit Control

Variable speed limit (VSL) control is a flexible restriction on the rate at which motorists can drive on a given stretch of road. Effective VSL control can increase safety and provide clear guidance for motorists. Previous traffic flow models of VSL control were mostly based on the influence of VSL on average speed (macro) or driver’s expected speed (micro). Few models considered the influence of VSL on driver’s actual driving behavior. In this paper, we first briefly introduce the big traffic data involved in this study and explain the mapping relationship between the data and driving behavior. Then, we analyze the driver’s actual driving behavior under the VSL control. Then, an improved single-lane cellular automaton model is established based on the driving behavior characteristics under VSL control. After that, we calibrate the parameters of the single-lane cellular automaton model with the left lane as the calibration object. Finally, this paper uses the proposed single-lane cellular automaton model to simulate the traffic flow characteristics under VSL control. The numerical simulation results show that the simulation of the variable speed limit in different density intervals presents different results, but these results are consistent with the actual situation of variable speed limit control, which verifies the validity of the proposed model.

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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