Download or read book Validating Traffic Simulation Models to Inclement Weather Travel Conditions with Applications to Arterial Coordinated Signal Systems in Northern New England written by Seli James Agbolosu-Amison and published by . This book was released on 2004 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Validating Traffic Simulation Models to Inclement Weather Travel Conditions with Applications to Arterial Coordinated Signal Systems written by Adel Wadid Sadek and published by . This book was released on 2004 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Traffic Simulation and Data written by Winnie Daamen and published by CRC Press. This book was released on 2014-09-17 with total page 261 pages. Available in PDF, EPUB and Kindle. Book excerpt: A single source of information for researchers and professionals, Traffic Simulation and Data: Validation Methods and Applications offers a complete overview of traffic data collection, state estimation, calibration and validation for traffic modelling and simulation. It derives from the Multitude Project-a European Cost Action project that incorpo
Download or read book Modelling Simulation and Control of Signalized Intersections Under Adverse Weather Conditions written by Zhengyang Lu and published by . This book was released on 2016 with total page 98 pages. Available in PDF, EPUB and Kindle. Book excerpt: Adverse winter weather has always been a cause of traffic congestion and road collisions. To mitigate the negative impacts of winter weather, transportation agencies have been introducing weather responsive traffic management strategies such as adaptive control of signalized intersections and variable speed limits. Currently, most traffic signal control systems are designed for normal weather conditions and are therefore suboptimal in terms of efficiency and safety for controlling traffic during winter snow events due to the changing traffic patterns and driver behavior. There is a lack of systemic guidance on weather responsive signal control from signal design manuals and guide books. Existing guidelines do not provide methodical approaches to help traffic operators determine how to deploy weather-responsive signal control strategies for a local network. Additionally, the magnitude of the benefits of implementing weather-responsive signal control strategies is largely unknown due to the lack of reliable evaluation tools. The main objectives of this thesis are therefore to develop quantitative understanding of the effects of winter weather on several key traffic parameters and to investigate the methods and potential of implementing weather-responsive signal control strategies during inclement winter weather conditions. This thesis research consists of three main components. First, we have examined the impacts of winter weather on two key traffic parameters, namely, saturation flow rate and start-up lost time. Field data including traffic video and road weather and surface conditions were collected in the winter of 2015, from which various traffic parameters were extracted from vehicle trajectories. Extensive statistical analyses, including categorical analysis, non-linear regression, and multivariate regression, were followed to develop models for the relationship between each traffic parameter and various influencing factors such as visibility, precipitation and road surface conditions. Second, we have focused on calibrating a microscopic simulation model that can be used to simulate traffic operations under adverse winter weather conditions. A video-based approach was proposed to calibrate three important driver behavior parameters, i.e., mean desired speed, median desired acceleration rate at speed 0, and a parameter reflecting mean safe following distance. This approach is more robust and reliable than the traditional calibration methods due to the fact that the individual parameters are estimated directly from field data in a physically consistent way as opposed to the traditional trial-and-error process. At last, we have investigated the potential benefits of implementing weather-specific signal control plans for isolated intersections as well as arterial corridors based on two case studies. For both case studies, three traffic demand scenarios, i.e., high, medium, and low, were considered. Evaluation results from both deterministic and simulation models show that implementing weather specific signal plans is most beneficial for intersections with a medium level of traffic demand. When the demand is very low or very high, such strategies has little benefit in terms of reducing traffic delay. It has also been found that the benefit of implementing weather-responsive plans is more compelling at an arterial-corridor level with signal coordination than at an isolated-intersection level.
Download or read book Federally Coordinated Program of Highway Research and Development written by United States. Federal Highway Administration and published by . This book was released on with total page 516 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Evaluation of Traffic Simulation Models for Supporting ITS Development written by Sharon Adams Boxill and published by . This book was released on 2000 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt: Tools to evaluate networks under information supply are a vital necessity in light of the systems being implemented as part of the Intelligent Transportation Systems (ITS) deployment plan. One such tool is the traffic simulation model. This report presents an evaluation of the existing traffic simulation models to identify the models that can be potentially applied in ITS equipped networks. The traffic simulation models are categorized according to type (macroscopic, microscopic or mesoscopic), as well as functionality (highway, signal, integrated). The entire evaluation is conducted through two steps: initial screening and in-depth evaluation. The initial step generates a shorter but more specific list of traffic simulation models based on some pre-determined criteria. The in-depth evaluation identifies which model on the shorter list is suitable for a specific area of ITS applications. It is concluded from this research that presently CORSIM and INTEGRATION appear to have the highest probability of success in real-world applications. It is also found that by adding more calibration and validation in the U.S., the AIMSUN 2 and PARAMICS models will be brought to the forefront in the near term for use with ITS applications.
Download or read book Application of Traffic Simulation Models written by and published by . This book was released on 1982 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Master s Theses Directories written by and published by . This book was released on 2005 with total page 316 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Education, arts and social sciences, natural and technical sciences in the United States and Canada".
Download or read book Where the Weather Meets the Road written by National Research Council (U.S.). Committee on Weather Research for Surface Transportation: The Roadway Environment and published by . This book was released on 2004-04-14 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt: Weather has broad and significant effects on the roadway environment. Snow, rain, fog, ice, freezing rain, and other weather conditions can impair the ability of drivers to operate their vehicles safely, significantly reduce roadway capacity, and dramatically increase travel times. Multiple roadway activities, from roadway maintenance and construction to shipping, transit, and police operations, are directly affected by inclement weather. Some road weather information is available to users currently, however a disconnect remains between current research and operations, and additional research could yield important safety and economic improvements for roadway users. Meteorology, roadway technology, and vehicle systems have evolved to the point where users could be provided with better road weather information through modern information technologies. The combination of these technologies has the potential to significantly increase the efficiency of roadway operations, road capacity, and road safety. Where the Weather Meets the Road provides a roadmap for moving these concepts to reality.
Download or read book Development and Evaluation of Model based Adaptive Signal Control for Congested Arterial Traffic written by Gang Liu and published by . This book was released on 2015 with total page 139 pages. Available in PDF, EPUB and Kindle. Book excerpt: Under congested conditions, the road traffic states of different arterial links will interact with each other; therefore, it is necessary to understand the behavior of traffic corridors and to investigate corridor-wide traffic coordinated control strategies. In order to achieve this, traffic flow models are applied in signal control to predict future traffic states. Optimization tools are used to search for the best sequence of future control decisions, based on predictions by traffic flow models. A number of model-based adaptive control strategies have been presented in the literature and have been proved effective in practice. However, most studies have modeled the traffic dynamic either at a link-based level or at an individual movement-based level. Moreover, the efficiency of corridor-wide coordination algorithms for congested large-scale networks still needs to be further improved. A hierarchical control structure is developed to divide the complex control problem into different control layers: the highest level optimizes the cycle length, the mid layer optimizes the offsets, and the Model Predictive Control (MPC) procedure is implemented in the lowest layer to optimize the split. In addition, there is an extra multi-modal priority control layer to provide priority for different travel modes. Firstly, MPC is applied to optimize the signal timing plans for arterial traffic. The objectives are to increase the throughput. A hybrid urban traffic flow model is proposed to provide relatively accurate predictions of the traffic state dynamic, which is capable of simulating queue evolutions among different lane groups in a specific link. Secondly, this study expands the dynamic queue concept to the corridor-wide coordination problem. The ideal offset and boundary offsets to avoid spillback and starvation are found based on the shockwave profiles at each signalized intersection. A new multi-objective optimization model based on the preemptive goal programming is proposed to find the optimal offset. Thirdly, the priority control problem is formulated into a multi-objective optimization model, which is solved with a Non-dominated Sorting Genetic Algorithm. Pareto-optimal front results are presented to evaluate the trade-off among different objectives and the most appropriate solution is chosen with high-level information. Performance of the new adaptive controller is verified with software-in-the-loop simulation. The applied simulation environment contains VISSIM with the ASC/3 module as the simulation environment and the control system as the solver. The simulation test bed includes two arterial corridors in Edmonton, Alberta. The simulation network was well calibrated and validated. The simulation results show that the proposed adaptive control methods outperform actuated control in increasing throughput, decreasing delay, and preventing queue spillback.
Download or read book Identifying and Assessing Key Weather related Parameters and Their Impacts on Traffic Operations Using Simulation written by Li Zhang and published by . This book was released on 2004 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Methodology for Traffic Signal Timing in Oversaturated Arterial Networks written by Gye-Hyeong Ahn and published by . This book was released on 1997 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt: A traffic simulation model was developed to provide a methodology for traffic signal timing in oversaturated urban arterial networks. Two control objectives of traffic signal timing in oversaturated conditions were taken into consideration. One was to maximize the number of vehicles processed in an arterial network, which has an oversaturated traffic demand at the entry of the arterial street and moderate traffic demands at the entry of cross streets. The other was to prevent queue spillback or to minimize the occurrence of queue spillback if inevitable. Signal timing offset was the dominant factor affecting system performance; although, link length was also important. When link length is short, the optimum offset is approximately zero, regardless of the cycle length. As link length increases beyond the minimum 200 ft (61 m) tested, for highest efficiency, downstream intersection greens should begin before upstream intersection greens. This relationship, opposite to conventional progression greens, moves downstream queues before incoming platoon arrival. Cross street traffic operations can have significant effects upon arterial performance and system efficiency. System efficiency rapidly deteriorates when any cross street green becomes too short for the link length. Therefore, a "practical" minimum green interval for cross streets is necessary to accommodate upstream cross street through traffic and turning vehicles from the arterial. When the cross street green is shorter than the minimum, even with the best offset combination, queue spillbacks occur on the cross streets and system efficiency deteriorates.
Download or read book R D Network Shadow Advanced Traffic Operations Center to Model Signal Timing for Severe Weather Conditions written by Peter T. Martin and published by . This book was released on 2000 with total page 85 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Modeling Estimation and Control of Traffic written by Dongyan Su and published by . This book was released on 2014 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation studies a series of freeway and arterial traffic modeling, estimation and control methodologies. First, it investigates the Link-Node Cell Transmission Model's (LN-CTM's) ability to model arterial traffic. The LN-CTM is a modification of the cell transmission model developed by Daganzo. The investigation utilizes traffic data collected on an arterial segment in Los Angeles, California, and a link-node cell transmission model, with some adaptations to the arterial traffic, is constructed for the studied location. The simulated flow and the simulation travel time were compared with field measurements to evaluate the modeling accuracy. Second, an algorithm for estimating turning proportions is proposed in this dissertation. The knowledge about turning proportions at street intersections is a frequent input for traffic models, but it is often difficult to measure directly. Compared with previous estimation methods used to solve this problem, the proposed method can be used with only half the detectors employed in the conventional complete detector configuration. The proposed method formulates the estimation problem as a constrained least squares problem, and a recursive solving procedure is given. A simulation study was carried out to demonstrate the accuracy and efficiency of the proposed algorithm. In addition to addressing arterial traffic modeling and estimation problems, this dissertation also studies a freeway traffic control strategy and a freeway and arterial coordinated control strategy. It presents a coordinated control strategy of variable speed limits (VSL) and ramp metering to address freeway congestion caused by weaving effects. In this strategy, variable speed limits are designed to maximize the bottleneck flow, and ramp metering is designed to minimize travel time in a model predictive control frame work. A microscopic simulation based on the I-80 at Emeryville, California was built to evaluate the strategy, and the results showed that the traffic performance was significantly improved . Following the freeway control study, this dissertation discusses the coordinated control of freeways and arterials. In current practice, traffic controls on freeways and on arterials are independent. In order to coordinate these two systems for better performance, a control strategy covering the freeway ramp metering and the signal control at the adjacent intersection is developed. This control strategy uses upstream ALINEA, which is a well-known control algorithm, for ramp metering to locally maximize freeway throughput. For the intersection signal control, the proposed control strategy distributes green splits by taking into account both the available on-ramp space and the demands of all intersection movements. A microscopic simulation of traffic in an arterial intersection with flow discharge to a freeway on-ramp, which is calibrated using the data collected at San Jose, California, is created to evaluate the performance of the proposed control strategy. The results showed that the proposed strategy can reduce intersection delay by 8%, compared to the current field-implemented control strategy. Transportation mobility can be improved not only by traffic management strategies, but also through the deployment of advanced vehicle technologies. This dissertation also investigates the impact of Adaptive Cruise Control (ACC) and Cooperative Adaptive Cruise Control (CACC) on highway capacity. A freeway microscopic traffic simulation model is constructed to evaluate how the freeway lane flow capacity change under different penetration rates of vehicles equipped with either ACC or CACC system. This simulation model is based on a calibrated driver behavioral model and the vehicle dynamics of the ACC and CACC systems. The model also utilizes data collected from a real experiment in which drivers' selections of time gaps are recorded. The simulation shows that highway capacity can be significantly increased when the CACC vehicles reach a moderate to high market penetration, as compared to both regular manually driven vehicles and vehicles equipped with only ACC.
Download or read book Validation of Arterial Travel time Estimation Models Using Field Data and Simulation written by Michael P. Dixon and published by . This book was released on 2007 with total page 54 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Selection of a Simulation Software to Model a Small Signalized System of a Multilane Arterial in the Southeastern US written by Elsa Gebru Tedla and published by . This book was released on 2009 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt: Employment of traffic simulation tools has become a popular practice in traffic operations analyses as the transportation system has become more complex and more frequently congested. Most of the commercially available traffic simulation models work best for free-flow or unsaturated conditions. Depending on the type of traffic condition and type of analysis, the performance of simulation models varies and there is little information available to help the analyst to select the most appropriate and accurate model for a given analysis. To address this need, two traffic simulation tools, SimTraffic and AIMSUN, were evaluated and compared for a congested arterial segment. Both simulation packages are designed to model almost any combination of surface street and freeway facilities. In this paper, an arterial segment in Tuscaloosa, Alabama (McFarland Boulevard) between 13th street and 31st street was coded and simulated for AM, Mid day, and PM peak periods. The network was simulated 10 times for each peak period using both simulation models, and average values were taken for comparison. Then the network was evaluated using output measures of effectiveness (MOE) such as Vehicle Hours Travel (VHT), Vehicle Miles Travel (VMT), average speed, and flow rate at the network level, along with delay, travel time, and average speed at the arterial level, and delay and traffic volume at a link level. Using statistical methods and graphical plots for comparison, each simulation model was evaluated for its capability to replicate existing field conditions using default and calibrated traffic parameters. In addition to accuracy, the models were also compared with respect to ease of coding, and quality/usefulness of output. This report documents relevant results and calibration processes used for employing the models in future studies and practices regarding congested arterials.
Download or read book Investigation of traffic simulation models for a signalised street network written by and published by . This book was released on 1967 with total page 522 pages. Available in PDF, EPUB and Kindle. Book excerpt:
