Proactive Strategy for Variable Speed Limit Operations on Freeways Under Foggy Weather Conditions

2016 ◽  
Vol 2551 (1) ◽  
pp. 29-36 ◽  
Author(s):  
Saerona Choi ◽  
Cheol Oh
Keyword(s):  
Weather Conditions ◽  
Speed Limit ◽  
Variable Speed ◽  
Variable Speed Limit

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.

Safety Effectiveness of Variable Speed Limit System in Adverse Weather Conditions on Challenging Roadway Geometry

2015 ◽  
Vol 2521 (1) ◽  
pp. 45-53 ◽  
Author(s):  
Promothes Saha ◽  
Mohamed M. Ahmed ◽  
Rhonda Kae Young
Keyword(s):  
Quantitative Measure ◽  
Weather Conditions ◽  
Speed Limit ◽  
Variable Speed ◽  
Variable Speed Limit ◽  
Explanatory Variables ◽  
Safety Performance Function ◽  
Distinct Variable ◽  
Adverse Weather Conditions ◽  
Adverse Weather

This paper examined the interaction between roadway geometric characteristics and adverse weather conditions and their impact on crash occurrence on rural variable speed limit freeway corridors through mountainous terrain. As a quantitative measure of the effect of geometrics in adverse weather conditions, a crash frequency safety performance function that used generalized linear regression was developed with explanatory variables including snow, ice, frost, wind, horizontal curvature, and steep grades. This research concluded that the interaction between grades and horizontal curves with weather variables had a significant impact on crash occurrence. The research suggested that distinct variable speed limit strategies should be implemented on segments with challenging roadway geometry.

Cycle-based variable speed limit methodology for improved freeway merging

2017 ◽  
Vol 11 (10) ◽  
pp. 632-640 ◽  
Author(s):  
Li Zhang ◽  
Lei Zhang ◽  
David K. Hale ◽  
Jia Hu ◽  
Zhitong Huang
Keyword(s):  
Speed Limit ◽  
Variable Speed ◽  
Variable Speed Limit

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.

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