Improving Intersection Safety Through Variable Speed Limits for Connected Vehicles PDF Download

Author: Michael W. Levin
Publisher:
ISBN:
Category : Automated vehicles
Languages : en
Pages : 34

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Book Description
Autonomous vehicles create new opportunities for innovative intelligent traffic systems. Variable speed limits, which is a speed management systems that can adjust the speed limit according to traffic condition or predefined speed control algorithm on different road segments, can be better implemented with the cooperation of autonomous vehicles. These compliant vehicles can automatically follow speed limits. However, non-compliant vehicles will attempt to pass the moving bottleneck created by the compliant vehicle. This project builds a multi class cell transmission model to represent the relation between traffic flow parameters. This model can calculate flows of both compliant and non-compliant vehicles. An algorithm is proposed to calculate variable speed limits for each cell of the cell transmission model. This control algorithm is designed to reduce the stop-and-go behavior of vehicles at traffic signals. Simulation is used to test the effects of VSLs on an example network. The result shows that VSL is effective at reducing the energy consumption of the whole system and reduce the likelihood of crash occurrence.

Author: Ellen F. Grumert
Publisher: Linköping University Electronic Press
ISBN: 9176853411
Category :
Languages : en
Pages : 93

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Book Description
Motorway traffic management systems are useful for improving the traffic conditions on urban motorways. One of the most common motorway traffic management systems are variable speed limit systems. These systems adapt the speed limits based on the prevailing traffic conditions measured by roadside detectors and recommended or compulsory speed limits are shown on variable message signs installed on gantries over the road.Thesystems consist of three parts; the control algorithm used to determine which speed limit to be displayed, a method for estimating the traffic conditions to be used as input for the control algorithm and the infrastructure for application of the variable speed limits. The goal of the systems is often to increase safety or efficiency. Recent development in the field of connected vehicles have opened up for a new type of data source, as the status of a connected vehicle and its surroundings can be communicated at arbitrary locations. Hence, by the use of connected vehicles in variable speed limit systems there is a potential of reducing the amount of roadside equipment. It is even possible to control the connected vehicles towards the current speed limit without the use of variable message signs. This allows for the application of variable speed limits at arbitrary locations. The aim of this thesis is to examine how connected vehicles can be used to improve the efficiency of variable speed limit systems. The thesis contribute with new and improved methods using connected vehicles in all three parts of a variable speed limit system. The suggested methods are evaluated by microscopic traffic simulation. The overall conclusion is that the use of connected vehicles in variable speed limit systems can contribute to improvements in traffic efficiency compared to existing systems. The six papers included in the thesis can be summarized as follows. First, it is shown that traditional variable speed limit systems can be effective for improving the traffic conditions on the motorway and the results can be comparable to more costly alterations by reconstruction of the infrastructure to increase the capacity. Next, the usefulness of connected vehicles for application and control of the speed limits in an existing variable speed limit system is investigated. It is concluded that the design of the control algorithm and the accuracy of the estimated traffic conditions have a great effect on the final outcome of the system. The design of the control algorithm is then examined by evaluation of a number of control algorithms with respect to safety, efficiency and environmental impacts. The main benefits and drawbacks of the algorithms are highlighted and desirable characteristics to include when designing a control algorithm are identified. In two studies, methods making use of connected vehicles for estimating the traffic conditions are proposed. The results show that connected vehicles are useful for improving the accuracy of the estimated traffic conditions through the inclusion of more detailed information and information at locations where detector measurements are not available. Finally, a variable speed limit system is proposed in which connected vehicles play a central role in the estimation of the traffic conditions, as well as in the control algorithm and for application of the speed limit. The system is shown to be useful for improving traffic efficiency during an incident at an arbitrary location along the controlled road.

Author: European Conference of Ministers of Transport
Publisher: OECD Publishing
ISBN: 9282103781
Category :
Languages : en
Pages : 286

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Book Description
Speeding is the number one road safety problem in a large number of OECD/ECMT countries. It is responsible for around one third of the current, unacceptably high levels of road fatalities. Speeding has an impact not only on accidents but also on the ...

Author: András Hegyi
Publisher:
ISBN:
Category : Express highways
Languages : en
Pages : 236

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Author:
Publisher: Transportation Research Board
ISBN: 9780309065023
Category : Business & Economics
Languages : en
Pages : 444

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Book Description
TRB Special Report 254 - Managing Speed: Review of Current Practices for Setting and Enforcing Speed Limits reviews practices for setting and enforcing speed limits on all types of roads and provides guidance to state and local governments on appropriate methods of setting speed limits and related enforcement strategies. Following an executive summary, the report is presented in six chapters and five appendices.

Author: Vijay Kumar Sabawat Krishna
Publisher:
ISBN: 9781303633812
Category : Intelligent transportation systems
Languages : en
Pages : 198

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Book Description
Variable Speed Limit (VSL) systems are an innovative way of managing traffic using Intelligent Transportation Systems (ITS). Unlike the traditional static speed limit signs, VSLs are speed limit signs with a capability of changing regulatory speed limits according to changing real time weather and traffic conditions. VSLs are primarily used to reduce traffic congestion and improve safety along roadways. Wyoming weather is highly variable and often severe, in the absence of recommended speed limits for such conditions drivers select their own safe driving speed leading to high variance among vehicles. This high speed variance, results in high crash rates and frequent road closures. Currently Wyoming Department of Transportation (WYDOT) using an interim manual protocol to deploy speed limits on VSL corridors. A new automated self-learning methodology for deploying VSL is described in this dissertation. As a first step in this project, weather variables that have a significant effect on vehicle speeds during bad weather conditions were identified using a robust regression statistical procedure. Second, an automated control strategy was designed that uses real time weather and observed speed variables. Third, a statistical model called decision trees was used in control strategy to enhance the performance of the automated control strategy. Fourth, a self-learning component is added to the control strategy to address concerns about the high variability of different storm events in this region. The proposed automated self-learning algorithm was tested on previous storm event datasets and results from the simulation indicate that the new system is more efficient than the current manual protocol of deploying speed limits. Finally, the transferability of the proposed control strategy was evaluated by applying the self-learning control strategy that was developed based on the storm data available at the Elk Mountain corridor to the storm data available at Laramie-Cheyenne corridor.

Author: Lee August Rodegerdts
Publisher: Transportation Research Board
ISBN: 0309155118
Category : Technology & Engineering
Languages : en
Pages : 407

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Book Description
TRB's National Cooperative Highway Research Program (NCHRP) Report 672: Roundabouts: An Informational Guide - Second Edition explores the planning, design, construction, maintenance, and operation of roundabouts. The report also addresses issues that may be useful in helping to explain the trade-offs associated with roundabouts. This report updates the U.S. Federal Highway Administration's Roundabouts: An Informational Guide, based on experience gained in the United States since that guide was published in 2000.

Author: Gereon Meyer
Publisher: Springer
ISBN: 3319948962
Category : Technology & Engineering
Languages : en
Pages : 247

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Book Description
This is the fifth volume of a sub series on Road Vehicle Automation published within the Lecture Notes in Mobility. Like in previous editions, scholars, engineers and analysts from all around the world have contributed chapters covering human factors, ethical, legal, energy and technology aspects related to automated vehicles, as well as transportation infrastructure and public planning. The book is based on the Automated Vehicles Symposium which was hosted by the Transportation Research Board (TRB) and the Association for Unmanned Vehicle Systems International (AUVSI) in San Francisco, California (USA) in July 2017.

Author: Wuhong Wang
Publisher: Springer Nature
ISBN: 9811956154
Category : Technology & Engineering
Languages : en
Pages : 719

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Book Description
These proceedings gather selected papers from the 12th International Conference on Green Intelligent Transportation Systems and Safety, held in Beijing, China on November 17-19, 2021. The book contains cutting-edge research on Green Intelligent Mobility Systems, with the goal of achieving "green, intelligent, and safe transportation systems" as the guiding slogan. The contributions offered here can aid in the advancement of green mobility and intelligent transportation technology by increasing interconnectivity, resource sharing, flexibility, and efficiency. Researchers and engineers in the areas of Transportation Technology and Traffic Engineering, Automotive and Mechanical Engineering, Industrial and System Engineering, and Electrical Engineering will all benefit from the book's scope.

Author: Abdulaziz Hebni Alshehri
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Book Description
Motor vehicles are the primary source of transportation in the United States. While this is true for any age group, the older population tend to rely more heavily on automobiles because of easy access and availability, compared to public transportation even when it is available. Older drivers aged 65 years and older are more vulnerable to fatal crashes due to cognitive impairments and frailty. When older drivers are involved in crashes, they sustain higher injury severities compared to younger drivers. One location where older driver experience higher crash risk is intersection, due to the complexity of the situation involving multiple tasks and movements. The objectives of this study were to determine risk factors associated with intersection-related crashes involving older drivers in the Midwestern states and to provide countermeasure ideas to improve safety. Five-year fatal crash data from 2014 to 2018 from the Fatality Analysis Reporting System (FARS) database were utilized, and statistical analysis was carried out to identify characteristics of fatal crashes involving older drivers and risk factors associated with intersection crashes among this age group. Three separate binary logistic regression models were developed to identify statistically significant predictor variables. First model represents older drivers who are involved in fatal single-vehicle crashes. Second model represents fatal multi-vehicle crashes involving at least one older driver, whereas the third model represents fatal single-vehicle crashes involving drivers younger than 65 years for comparison purposes. The dependent variable is whether a fatal crash occurs at an intersection location or not. Many independent variables that include various crash, driver, vehicle, and environmental factors were considered. By considering a 95 percent confidence level, odds ratios were estimated and used to identify relative risk factors of fatal intersection crashes. Analysis showed that controlled intersections, two-way undivided highways, and roads with posted speed limits less than 55 mph increased the risk of fatal single-vehicle and multi-vehicle crashes for older drivers. Fatal single-vehicle crashes were especially prevalent for these drivers. Factors such as urban roadways, driver age older than 75 years, nighttime driving, and speeding increased the risk of single-vehicle fatal intersection crashes, while turning movements and intersecting paths, straight and level roadways, two-lanes highway, and violation of roadway rules increased the risk of multi-vehicle fatal intersection crashes for older drivers. Single-vehicle fatal intersection crash analysis also showed that controlled intersections, two-way undivided highways, roads with posted speed limits less than 55 mph, urban roadways, speeding, nighttime driving, and fixed objects increased the risk of intersection-related fatal single-vehicle crashes, especially for older drivers. However, factors such as straight and level roadways, impaired driving, driver obesity, and the operation of recreation vehicles, buses, or motorcycles increased the risk of single-vehicle fatal intersection crashes for drivers in other age categories. Based on model results, countermeasure ideas to improve the safety of older drivers at intersections as well as other road users were identified. Among suggested ideas, improving intersections designs to accommodate older driver needs is recommended, such as implementing roundabouts when it is appropriate, reach minimum of 75-degree skew angel at intersection, providing protected left turn signals, flashing yellow arrow, restricted crossing U-turn, median U-turn, using rumble stripes along the side of roadway and median, providing transverse rumble strips (TRS) at intersections, improving roadway lighting, signs and markings at intersections and interchanges, implementing roadway diet, enhancing roadway signs and retroreflective delineation, providing cable, guardrail, or concrete barriers, implementing continuous raised-curb medians, enhancing lane drop marking on interchanges, providing acceleration and deceleration lane for merging and diverging locations, providing fixed or portable changeable message signs, enhancing high friction surface treatments on risk prone locations, increasing contrast markings on concrete pavement. Beside the engineering countermeasures, using newer vehicles that equipped with many safety features is advisable to enhance older and other drivers' safety. In addition, older driver license renewal may be modified to be required yearly to overcome early signs of fatigue or cognitive decline to reduce fatal crash risks and enhance safety. Therefore, the results and suggested countermeasures can provide guidance to improve safety of older drivers and other road users.