scholarly journals Analyzing the Safety Impacts of Variable Speed Limit Control on Aggregated Driving Behavior Based on Traffic Big Data

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Xu Qu ◽  
Mofeng Yang ◽  
Junyi Ji ◽  
Linheng Li ◽  
Bin Ran
Keyword(s):  
Big Data ◽  
Traffic Safety ◽  
Weather Conditions ◽  
Driving Behavior ◽  
Speed Limit ◽  
Variable Speed ◽  
Small Space ◽  
Real World Data ◽  
Variable Speed Limit ◽  
Speed Difference

Variable speed limit (VSL) control dynamically adjusts the displayed speed limit to harmonize traffic speed, prevent congestions, and reduce crash risks based on prevailing traffic stream and weather conditions. Previous research studies examine the impacts of VSL control on reducing corridor-level crash risks and improving bottleneck throughput. However, less attention focuses on utilizing real-world data to see how compliant the drivers are under different VSL values and how the aggregated driving behavior changes. This study aims to fill the gap. With the high-resolution lane-by-lane traffic big data collected from a European motorway, this study performs statistical analysis to measure the difference in driving behavior under different VSL values and analyze the safety impacts of VSL controls on aggregate driving behaviors (mean speed, average speed difference, and the percentage of small space headway). The data analytics show that VSL control can effectively decrease the mean speed, the speed difference, and the percentage of small space headways. The safety impacts of VSL control on aggregated driving behavior are also discussed. The aggregated driving behavior variables follow a trend of first decreasing and then increasing with the continuous decrease in VSL values, indicating that potential traffic safety benefits can be achieved by adopting suitable VSL values that match with prevailing traffic conditions.

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.

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.

Q-Learning-Based Coordinated Variable Speed Limit and Hard Shoulder Running Control Strategy to Reduce Travel Time at Freeway Corridor

2020 ◽  
Vol 2674 (11) ◽  
pp. 915-925
Author(s):  
Weiyi Zhou ◽  
Mofeng Yang ◽  
Minha Lee ◽  
Lei Zhang
Keyword(s):  
Travel Time ◽  
Control Strategy ◽  
Dynamic Traffic Assignment ◽  
Control Strategies ◽  
Speed Limit ◽  
Variable Speed ◽  
Real World Data ◽  
Variable Speed Limit ◽  
Q Learning ◽  
Freeway Corridor

To increase traffic mobility and safety, several types of active traffic management (ATM) strategies, such as variable speed limit (VSL), ramp metering, dynamic message signs, and hard shoulder running (HSR), are adopted in many countries. While all kinds of ATM strategies show promise in releasing traffic congestion, many studies indicate that stand-alone strategies have very limited capability. To remedy the defects of stand-alone strategies, cooperative ATM strategies have caught researchers’ attention and different combinations have been studied. In this paper, a coordinated VSL and HSR control strategy based on a reinforcement learning technique—Q-learning—is proposed. The proposed control strategy bridges up a direct connection between the traffic flow data and the ATM control strategies via intensive self-learning processes, thus reducing the need for human knowledge. A typical congested interstate highway, I-270 in Maryland, United States, was selected as the study area to evaluate the proposed strategy. A dynamic traffic assignment simulation model was introduced to calibrate the network with real-world data and was used to evaluate the regional impact of the proposed algorithm. Simulation results indicated that the proposed coordinated control could reduce corridor travel time by up to 27%. The performance of various control strategies were also compared. The results suggested that the proposed strategy outperformed the stand-alone control strategies and the traditional feedback-based VSL strategy in mitigating congestion and reducing travel time on the freeway corridor.

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.

scholarly journals Integrated variable speed limit and ramp metering control study on flow interaction between mainline and ramps

2019 ◽  
Vol 11 (3) ◽  
pp. 168781401983191 ◽  
Author(s):  
Xu Wang ◽  
Lei Niu
Keyword(s):  
Traffic Safety ◽  
Integrated Control ◽  
Simulation Models ◽  
Ramp Metering ◽  
Speed Limit ◽  
Variable Speed ◽  
Variable Speed Limit ◽  
Error Sources ◽  
Prediction And Simulation ◽  
Varying Demand

During peak periods, bottlenecks are often triggered by excessive demand from both on-ramp and mainline input flows. To relieve bottleneck severity and improve traffic safety, ramp metering and variable speed limit are implemented to control the on-ramp and mainline input flows, and sometimes they are integrated. This article presents a proactive integrated control, with goals to save network-wide travel time and increase traffic flow. A METANET-based macroscopic traffic model was adopted as a prediction model. Micro-simulation tests were performed to evaluate and compare the control approaches among integrated and isolated control scenarios. By decoupling the traffic prediction and simulation models, the control error sources were analyzed. The evaluation revealed that both isolated and integrated controls benefit the traffic network to different extents under varying demand scenarios. Under proactive integrated control, ramp metering is activated solely during slight congestion; or it is activated during high-congestion periods to assist variable speed limit and thus integration maximizes the infrastructure utility.

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