Author: Zhibin LiPublisher:
ISBN:
Category :
Languages : en
Pages : 46
Book Description
Enhancing Safe Traffic Operations Using Connected Vehicles Data and Technologies
Author: Zhibin LiEnhanced Traffic Signal Operation Using Connected Vehicle Data
Author: Ehsan BagheriPublisher:
ISBN:
Category : Intelligent transportation systems
Languages : en
Pages : 168
Book Description
As traffic on urban road network increases, congestion and delays are becoming more severe. At grade intersections form capacity bottlenecks in urban road networks because at these locations, capacity must be shared by competing traffic movements. Traffic signals are the most common method by which the right of way is dynamically allocated to conflicting movements. A range of traffic signal control strategies exist including fixed time control, actuated control, and adaptive traffic signal control (ATSC). ATSC relies on traffic sensors to estimate inputs such as traffic demands, queue lengths, etc. and then dynamically adjusts signal timings with the objective to minimize delays and stops at the intersection. Despite, the advantages of these ATSC systems, one of the barriers limiting greater use of these systems is the large number of traffic sensors required to provide the essential information for their signal timing optimization methodologies. A recently introduced technology called connected vehicles will make vehicles capable of providing detailed information such as their position, speed, acceleration rate, etc. in real-time using a wireless technology. The deployment of connected vehicle technology would provide the opportunity to introduce new traffic control strategies or to enhance the existing one. Some work has been done to-date to develop new ATSC systems on the basis of the data provided by connected vehicles which are mainly designed on the assumption that all vehicles on the network are equipped with the connected vehicle technology. The goals of such systems are to: 1) provide better performance at signalized intersections using enhanced algorithms based on richer data provided by the connected vehicles; and 2) reduce (or eliminate) the need for fixed point detectors/sensors in order to reduce deployment and maintenance costs. However, no work has been done to investigate how connected vehicle data can improve the performance of ATSC systems that are currently deployed and that operate using data from traditional detectors. Moreover, achieving a 100% market penetration of connected vehicles may take more than 30 years (even if the technology is mandated on new vehicles). Therefore, it is necessary to provide a solution that is capable of improving the performance of signalized intersections during this transition period using connected vehicle data even at low market penetration rates. This research examines the use of connected vehicle data as the only data source at different market penetration rates aiming to provide the required inputs for conventional adaptive signal control systems. The thesis proposes various methodologies to: 1) estimate queues at signalized intersections; 2) dynamically estimate the saturation flow rate required for optimizing the timings of traffic signals at intersections; and 3) estimate the free flow speed on arterials for the purpose of optimizing offsets between traffic signals. This thesis has resulted in the following findings: 1. Connected vehicle data can be used to estimate the queue length at signalized intersections especially for the purpose of estimating the saturation flow rate. The vehicles' length information provided by connected vehicles can be used to enhance the queue estimation when the traffic composition changes on a network. 2. The proposed methodology for estimating the saturation flow rate is able to estimate temporally varying saturation flow rates in response to changing network conditions, including lane blockages and queue spillback that limit discharge rates, and do so with an acceptable range of errors even at low level of market penetration of connected vehicles. The evaluation of the method for a range of traffic Level of Service (LOS) shows that the maximum observed mean absolute relative error (6.2%) occurs at LOS F and when only 10% of vehicles in the traffic stream are connected vehicles. 3. The proposed method for estimating the Free Flow Speed (FFS) on arterial roads can provide estimations close to the known ground truth and can respond to changes in the FFS. The results also show that the maximum absolute error of approximately 4.7 km/h in the estimated FFS was observed at 10% market penetration rate of connected vehicles. 4. The results of an evaluation of an adaptive signal control system based on connected vehicle data in a microsimulation environment show that the adaptive signal control system is able to adjust timings of signals at intersections in response to changes in the saturation flow rate and free flow speed estimated from connected vehicle data using the proposed methodologies. The comparison of the adaptive signal control system against a fixed time control at 20% and 100% CV market penetration rates shows improvements in average vehicular delay and average number of stops at both market penetration rates and though improvements are larger for 100% CV LMP, approximately 70% of these improvements are achieved at 20% CV LMP.
Using Connected Vehicles in Variable Speed Limit Systems:
Author: Ellen F. GrumertPublisher: Linköping University Electronic Press
ISBN: 9176853411
Category :
Languages : en
Pages : 93
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.
ITS Sensors and Architectures for Traffic Management and Connected Vehicles
Author: Lawrence A. KleinPublisher: CRC Press
ISBN: 1351800965
Category : Technology & Engineering
Languages : en
Pages : 518
Book Description
An intelligent transportation system (ITS) offers considerable opportunities for increasing the safety, efficiency, and predictability of traffic flow and reducing vehicle emissions. Sensors (or detectors) enable the effective gathering of arterial and controlled-access highway information in support of automatic incident detection, active transportation and demand management, traffic-adaptive signal control, and ramp and freeway metering and dispatching of emergency response providers. As traffic flow sensors are integrated with big data sources such as connected and cooperative vehicles, and cell phones and other Bluetooth-enabled devices, more accurate and timely traffic flow information can be obtained. The book examines the roles of traffic management centers that serve cities, counties, and other regions, and the collocation issues that ensue when multiple agencies share the same space. It describes sensor applications and data requirements for several ITS strategies; sensor technologies; sensor installation, initialization, and field-testing procedures; and alternate sources of traffic flow data. The book addresses concerns related to the introduction of automated and connected vehicles, and the benefits that systems engineering and national ITS architectures in the US, Europe, Japan, and elsewhere bring to ITS. Sensor and data fusion benefits to traffic management are described, while the Bayesian and Dempster–Shafer approaches to data fusion are discussed in more detail. ITS Sensors and Architectures for Traffic Management and Connected Vehicles suits the needs of personnel in transportation institutes and highway agencies, and students in undergraduate or graduate transportation engineering courses.
Connected Vehicle Systems
Author: Yunpeng WangPublisher: CRC Press
ISBN: 1351869515
Category : Computers
Languages : en
Pages : 298
Book Description
Connected vehicles and intelligent vehicles have been identified as key technologies for increasing road safety and transport efficiency. This book presents and discusss the recent advances in theory and practice in connected vehicle systems. It covers emerging research that aims at dealing with the challenges in designing the essential functional components of connected vehicles. Major topics include intra- and inter-vehicle communications, mobility model of fleet and ramp merging, trace and position data analysis, security and privacy.
Potential Connected Vehicle Applications to Enhance Mobility, Safety, and Environmental Security
Author: Xiaosi ZengPublisher:
ISBN:
Category : Intelligent transportation systems
Languages : en
Pages : 94
Book Description
Proceedings of the Twelfth International Conference on Management Science and Engineering Management
Author: Jiuping XuPublisher: Springer
ISBN: 3319933515
Category : Technology & Engineering
Languages : en
Pages : 1752
Book Description
This proceedings book is divided in 2 Volumes and 8 Parts. Part I is dedicated to Decision Support System, which is about the information system that supports business or organizational decision-making activities; Part II is on Computing Methodology, which is always used to provide the most effective algorithm for numerical solutions of various modeling problems; Part III presents Information Technology, which is the application of computers to store, study, retrieve, transmit and manipulate data, or information in the context of a business or other enterprise; Part IV is dedicated to Data Analysis, which is a process of inspecting, cleansing, transforming, and modeling data with the goal of discovering useful information, suggesting conclusions, and supporting decision-making; Part V presents papers on Operational Management, which is about the plan, organization, implementation and control of the operation process; Part VI is on Project Management, which is about the initiating, planning, executing, controlling, and closing the work of a team to achieve specific goals and meet specific success criteria at the specified time in the field of engineering; Part VII presents Green Supply Chain, which is about the management of the flow of goods and services based on the concept of “low-carbon”; Part VIII is focused on Industry Strategy Management, which refers to the decision-making and management art of an industry or organization in a long-term and long-term development direction, objectives, tasks and policies, as well as resource allocation.
Traffic Operations Assessment
Author: Andalib ShamsPublisher:
ISBN: 9780438386204
Category : Automobiles
Languages : en
Pages : 76
Book Description
As traffic congestion increases day by day, it becomes necessary to improve the existing roadway facilities to maintain satisfactory operational and safety performances. Moreover, Deployment of Connected and Autonomous Vehicles (CAV) will increase roadway capacity, but their induced demand may lead to further congestion. Increasing roadway capacity can reduce traffic congestion up to a certain extent, but it can be very costly and sometimes conventional methods are not suitable enough. Using innovative intersection designs, such as the Continuous Flow Intersection (CFI), instead of conventional four-legged intersections, have proven to be beneficial in increasing capacity and reducing congestion. Public transit systems that run in mixed traffic also experience increased travel times and reduction in reliability due to the increased levels of congestion. Implementing transit preferential treatments, often in conjunction with rapid transit modes, is a proven way to improve transit operations along congested corridors. This study focuses on assessing future traffic and transit conditions in year 2040, and potential improvement alternatives along sections of Redwood Road in Salt Lake and Utah Counties, Utah through VISSIM traffic simulation. In addition to the models of existing conditions, five scenarios were developed for 2040: Do-Nothing, Street Widening, implementation of a CFI, Transit Exclusive Lanes, and implementation of Transit Signal Priority (TSP) in conjunction with exclusive lanes. Among the developed scenarios, CFI scenario have been implemented only at the intersection of 9000 S and Redwood Road. Results suggests that, without any improvement, it would be impossible to maintain a satisfactory level of performance in 2040. In the street widening scenario number of lane have been updated to four. This street widening scenario is a possible improvement option, but still underperforms along certain segments and intersections. The conventional four-legged intersection of Redwood Road and 9000 S was replaced with a CFI, which helped in reducing the total delay for both passenger cars and transit. In the Transit Exclusive Lane scenario a lane have been added over the street widening scenario exclusively for transits. So, in this scenario four lanes are for vehicles and one lane is dedicated for transits. Transit exclusive lanes reduced the total intersection transit delay by 20% compared to Do-Nothing. The Transit Signal Priority scenario have been included over the Transit Exclusive Lane scenario. Combining TSP with transit exclusive lanes resulted in a 61% reduction in transit delays, while the vehicular traffic along the corridor also benefited from it. The cross street traffic mostly benefited from street widening, while it experienced some impact with TSP, although it was not statistically significant. TSP also performed well at the introduced CFI, where transit experienced 42% reduction in delay, with an improved performance for vehicular traffic compared to Do-Nothing. In the recent years, improvements in vehicular technology has been significant. Even after this improvement, right now it is only a fraction of what is being expected in the future. Vehicles in the future will be able to sense its environment and navigate the surroundings without any sort of human input. Moreover, vehicles will be able to communicate with other vehicles, infrastructures, pedestrians, and the cloud. These vehicles are introduced as Connected and Autonomous Vehicles. Driving behavior of these vehicles will be different than conventional vehicles. With the help of automation, these vehicles will have a shorter headway, faster perception-reaction time and more uniform speed than conventional vehicles. Using connected technology, vehicles will be able to form platoons and optimize their speed profile and routing decisions. Though it is known that CAV will act more cooperatively than conventional vehicles, there is little development in the improvement of driving behaviors or intersection control strategies to make them more cooperative. Considering these issues, this study developed signalized intersection control strategy algorithm based on TSP and tested the performance of the Intelligent Driver Model which does not consider the human-reaction time along with the developed algorithm. For the developed algorithms it has been assumed that vehicles are fully connected and the automation level is at least four. Alternative scenarios have been developed over the 2040 Do-Nothing scenario with 25%, 50%, 75% and 100% CAV penetration. CAV’s performance has also been assessed in comparison with the Transit Signal Priority scenario which includes all the traditional and innovative improvement strategies implemented in this study. Results suggest that travel delay at intersections and travel time at road segment would decrease with the increase in CAV penetration. Overall network delay and travel time would also decrease with increased CAV penetration. Though initially number of stops increased and average speed decreased, with more penetration both of the parameter performs better.
ITS Sensors and Architectures for Traffic Management and Connected Vehicles
Author: Lawrence A. KleinPublisher: CRC Press
ISBN: 1351800973
Category : Technology & Engineering
Languages : en
Pages : 574
Book Description
An intelligent transportation system (ITS) offers considerable opportunities for increasing the safety, efficiency, and predictability of traffic flow and reducing vehicle emissions. Sensors (or detectors) enable the effective gathering of arterial and controlled-access highway information in support of automatic incident detection, active transportation and demand management, traffic-adaptive signal control, and ramp and freeway metering and dispatching of emergency response providers. As traffic flow sensors are integrated with big data sources such as connected and cooperative vehicles, and cell phones and other Bluetooth-enabled devices, more accurate and timely traffic flow information can be obtained. The book examines the roles of traffic management centers that serve cities, counties, and other regions, and the collocation issues that ensue when multiple agencies share the same space. It describes sensor applications and data requirements for several ITS strategies; sensor technologies; sensor installation, initialization, and field-testing procedures; and alternate sources of traffic flow data. The book addresses concerns related to the introduction of automated and connected vehicles, and the benefits that systems engineering and national ITS architectures in the US, Europe, Japan, and elsewhere bring to ITS. Sensor and data fusion benefits to traffic management are described, while the Bayesian and Dempster–Shafer approaches to data fusion are discussed in more detail. ITS Sensors and Architectures for Traffic Management and Connected Vehicles suits the needs of personnel in transportation institutes and highway agencies, and students in undergraduate or graduate transportation engineering courses.
Deep Learning Based on Connected Vehicles
Author: Jiajie HuPublisher:
ISBN:
Category : Automated vehicles
Languages : en
Pages : 143
Book Description
The connected vehicle is an emerging technology aimed at deploying and developing a fully connected transportation system which allows the vehicles to dynamically transmit messages between the vehicles (V2V), infrastructure (V2I), Cloud (V2C) and everything (V2X). The connected vehicles can provide an unprecedented amount of data even in the traffic network with a low market penetration rate, which can provide new solutions to transportation issues. This study focuses on micromodeling and quantitatively assessing the potential benefits of the connected vehicles on safety, mobility, and energy efficiency perspectives. In this dissertation, we proposed deep-learning based systems to solve different transportation problems under the environment of connected vehicles. The crash risk prediction system can identify crash-prone intersections and guide the deployment of safety measures to prevent potential crashes. The pothole detection system provides a cost-effective strategy to map the road conditions, which will be beneficial to road maintenance especially when municipal budgets are limited. The slippery condition surveillance system achieves real-time monitoring of pavement slippery conditions impacted by adverse weather and promotes cautious driving behaviors. The adaptive traffic signal control system provides an adaptive, efficient and optimized traffic signal control agent, which can reduce vehicle delay and emissions, improve mobility and energy efficiency. Overall, connected vehicle technology shows great potential in the field of transportation. The safety, mobility and energy efficiency will be further improved with the widespread deployment of connected vehicles and increase of market penetration rate, which is achievable in the near future.