Stop Sign Gap Assist Application in a Connected Vehicle Simulation Environment

2021 ◽  
pp. 036119812110061
Author(s):  
Mahmoud Arafat ◽  
Mohammed Hadi ◽  
Thodsapon Hunsanon ◽  
Kamar Amine
Keyword(s):  
Simulation Models ◽  
Utilization Rate ◽  
Connected Vehicle ◽  
Acceptance Probability ◽  
Vehicle Simulation ◽  
Unsignalized Intersections ◽  
Trade Offs ◽  
Stop Sign ◽  
Study Results ◽  
Gap Time

Assessment of the safety and mobility impacts of connected vehicles (CVs) and cooperative automated vehicle applications is critical to the success of these applications. In many cases, there may be trade-offs in the mobility and safety impacts depending on the setting of the parameters of the applications. This study developed a method to evaluate the safety and mobility benefits of the Stop Sign Gap Assist (SSGA) system, a CV-based application at unsignalized intersections, which utilizes a calibrated microscopic simulation tool. The study results confirmed that it was critical to calibrate the drivers’ gap acceptance probability distributions in the utilized simulation model to reflect real-world driver behaviors when assessing SSGA impacts. The simulation models with the calibrated gap parameters were then used to assess the impacts of the SSGA. The results showed that SSGA can potentially improve overall minor approach capacity at unsignalized intersections by approximately 35.5% when SSGA utilization reaches 100%. However, this increase in capacity depended on the setting of the minimum gap time in the SSGA and there was a clear trade-off between capacity and safety. The analysis indicated that as the minimum gap time used in the SSGA increased, the safety of the intersection increased, showing for example that with the utilization of an 8-s gap at a 750 vph main street flow rate, the number of conflicts could decrease by 30% as the SSGA utilization rate increased from 0% to 100%.

Evaluating the Benefits of Red-Light Violation Warning System in a Connected Vehicle Simulation Environment

2021 ◽  
pp. 036119812110266
Author(s):  
Mohammed Hadi ◽  
Kamar Amine ◽  
Thodsapon Hunsanon ◽  
Mahmoud Arafat
Keyword(s):  
Rapid Development ◽  
Red Light ◽  
Warning System ◽  
Simulation Models ◽  
Signalized Intersections ◽  
Utilization Rate ◽  
Connected Vehicle ◽  
Microscopic Simulation ◽  
Vehicle Simulation ◽  
Study Results

The rapid development of connected vehicle (CV) and cooperative automated vehicle (CAV) technologies in recent years calls for the assessment of the impacts of these technologies on system performance. Microscopic simulation can play a major role in assessing these impacts, particularly during the early stages of the adoption of the technologies and associated applications. This study develops a method to evaluate the safety benefits of red-light violation warning (RLVW), a CV-based vehicle-to-infrastructure (V2I) application at signalized intersections, utilizing simulation. The study results confirm that it is critical to calibrate the probability to stop on amber in the utilized simulation model to reflect real-world driver behaviors when assessing RLVW impacts. Without calibration, the model is not able to assess the benefits of RLVW in reducing RLR and right-angle conflicts. Based on a surrogate safety assessment, the calibrated simulation models result shows that the CV-based RLVW can enhance the safety at signalized intersections by approximately 50.7% at 100% utilization rate of the application, considering rear-end, and right-angle conflicts.

Understanding Gap Acceptance Behavior at Unsignalized Intersections using Naturalistic Driving Study Data

2021 ◽  
pp. 036119812110071
Author(s):  
Yingfeng (Eric) Li ◽  
Haiyan Hao ◽  
Ronald B. Gibbons ◽  
Alejandra Medina
Keyword(s):  
Road Traffic ◽  
Wait Time ◽  
Study Data ◽  
Gap Acceptance ◽  
Factors Affecting ◽  
Unsignalized Intersections ◽  
Research Activities ◽  
Stop Sign ◽  
Naturalistic Driving Study ◽  
Naturalistic Driving

Even though drivers disregarding a stop sign is widely considered a major contributing factor for crashes at unsignalized intersections, an equally important problem that leads to severe crashes at such locations is misjudgment of gaps. This paper presents the results of an effort to fully understand gap acceptance behavior at unsignalized intersections using SHPR2 Naturalistic Driving Study data. The paper focuses on the findings of two research activities: the identification of critical gaps for common traffic/roadway scenarios at unsignalized intersections, and the investigation of significant factors affecting driver gap acceptance behaviors at such intersections. The study used multiple statistical and machine learning methods, allowing a comprehensive understanding of gap acceptance behavior while demonstrating the advantages of each method. Overall, the study showed an average critical gap of 5.25 s for right-turn and 6.19 s for left-turn movements. Although a variety of factors affected gap acceptance behaviors, gap size, wait time, major-road traffic volume, and how frequently the driver drives annually were examples of the most significant.

scholarly journals Decision Support for the (Inter-)Basin Management of Water Resources Using Integrated Hydro-Economic Modeling

Hydrology ◽  
2021 ◽  
Vol 8 (1) ◽  
pp. 42
Author(s):  
Gerald Norbert Souza da Silva ◽  
Márcia Maria Guedes Alcoforado de Moraes
Keyword(s):  
Decision Support ◽  
Water Resources ◽  
Water Allocation ◽  
Hydrological Modeling ◽  
Well Being ◽  
Water Transfer ◽  
Economic Modeling ◽  
Trade Offs ◽  
Study Results

The development of adequate modeling at the basin level to establish public policies has an important role in managing water resources. Hydro-economic models can measure the economic effects of structural and non-structural measures, land and water management, ecosystem services and development needs. Motivated by the need of improving water allocation using economic criteria, in this study, a Spatial Decision Support System (SDSS) with a hydro-economic optimization model (HEAL system) was developed and used for the identification and analysis of an optimal economic allocation of water resources in a case study: the sub-middle basin of the São Francisco River in Brazil. The developed SDSS (HEAL system) made the economically optimum allocation available to analyze water allocation conflicts and trade-offs. With the aim of providing a tool for integrated economic-hydrological modeling, not only for researchers but also for decision-makers and stakeholders, the HEAL system can support decision-making on the design of regulatory and economic management instruments in practice. The case study results showed, for example, that the marginal benefit function obtained for inter-basin water transfer, can contribute for supporting the design of water pricing and water transfer decisions, during periods of water scarcity, for the well-being in both basins.

Capturing Effects of Maintenance Practices in Highway Asset Valuation: Replacement-Cost Approach Versus Book-Value Method

2003 ◽  
Vol 1824 (1) ◽  
pp. 57-65 ◽  
Author(s):  
Poovadol Sirirangsi ◽  
Adjo Amekudzi ◽  
Pannapa Herabat
Keyword(s):  
Pavement Management ◽  
Added Value ◽  
Replacement Cost ◽  
Asset Valuation ◽  
Book Value ◽  
Cost Approach ◽  
Trade Offs ◽  
Study Results ◽  
Asset Value ◽  
The Impact

The replacement-cost approach and the book-value method as decision support tools for selecting maintenance alternatives under budget constraints and for capturing the effects of maintenance practices on highway asset value are investigated. By using a case study based on the Thailand Pavement Management System, the replacement-cost approach and the book-value method are applied to analyze maintenance alternatives for selected highways. The versatility of these asset-valuation methods is explored for capturing trade-offs in the type and timing of maintenance and for incorporating the added value of effective maintenance practices and the impact of deferred maintenance in the overall asset value. The study demonstrated that the replacement-cost approach is a more versatile tool for considering the maintenance-related value of highways in maintenance decision making, whereas the book value may be a simpler financial accounting tool. The two approaches may be used together to clarify how maintenance expenditures are being translated into facility replacement value or how the overall value of the infrastructure is being preserved. The study results are potentially useful to agencies interested in capturing the added value of effective maintenance practices in the overall value of their asset base.

Clonal testing efficiency: the trade-offs between clones tested and ramets per clone

1986 ◽  
Vol 16 (5) ◽  
pp. 925-930 ◽  
Author(s):  
J. H. Russell ◽  
W. J. Libby
Keyword(s):  
Clonal Selection ◽  
Simulation Models ◽  
Radiata Pine ◽  
Fixed Number ◽  
Broad Sense ◽  
Optimum Level ◽  
Broad Sense Heritability ◽  
Selection Intensity ◽  
Trade Offs ◽  
Clonal Testing

Three contrasting simulation models were developed to investigate testing efficiencies in a clonal selection program. The variables investigated were number of total plants tested, number of candidate clones tested, number of ramets per clone, number of clones selected, selection intensity, and broad-sense heritability. The model deemed appropriate to most clonal forestry situations selected a fixed number of clones in an experiment with the total number of plants in the test held constant. In this model, as the number of ramets per clone was varied, the number of candidate clones tested and the selection intensity necessarily also varied. This model indicates that cloning individuals for testing is useful when selection is based on a characteristic or index with broad-sense heritability less than about 0.6. At the lower heritabilities, two to six ramets per clone per site usually produces the optimum level of cloning, the exact number depending upon the selection intensity and heritability. Predictions generated by this fixed number of selected clones model were compared with average phenotypic values of selections using different subsamples of data for 8-year height and for 8-year diameter in a radiata pine (Pinusradiata D. Don) clonal experiment. Agreement between predictions and average phenotypic values in both these two comparisons was close.

scholarly journals The Risks and Benefits of Providing HIV Services during the COVID-19 Pandemic

2021 ◽  
Author(s):  
John Stover ◽  
Sherrie L. Kelly ◽  
Edinah Mudimu ◽  
Dylan Green ◽  
Tyler Smith ◽  
...  
Keyword(s):  
Health Services ◽  
Health Workers ◽  
Diagnostic Testing ◽  
Simulation Models ◽  
Hiv Infections ◽  
Early Response ◽  
Voluntary Medical Male Circumcision ◽  
Medical Male Circumcision ◽  
Hiv Services ◽  
Trade Offs

AbstractIntroductionThe COVID-19 pandemic has caused widespread disruptions including to health services. In the early response to the pandemic many countries restricted population movements and some health services were suspended or limited. In late 2020 and early 2021 some countries re-imposed restrictions. Health authorities need to balance the potential harms of additional SARS-CoV-2 transmission due to contacts associated with health services against the benefits of those services, including fewer new HIV infections and deaths. This paper examines these trade-offs for select HIV services.MethodsWe used four HIV simulation models (Goals, HIV Synthesis, Optima HIV and EMOD) to estimate the benefits of continuing HIV services in terms of fewer new HIV infections and deaths. We used three COVID-19 transmission models (Covasim, Cooper/Smith and a simple contact model) to estimate the additional deaths due to SARS-CoV-2 transmission among health workers and clients. We examined four HIV services: voluntary medical male circumcision, HIV diagnostic testing, viral load testing and programs to prevent mother-to-child transmission. We compared COVID-19 deaths in 2020 and 2021 with HIV deaths occurring now and over the next 50 years discounted to present value. The models were applied to countries with a range of HIV and COVID-19 epidemics.ResultsMaintaining these HIV services could lead to additional COVID-19 deaths of 0.002 to 0.15 per 10,000 clients. HIV-related deaths averted are estimated to be much larger, 19 - 146 discounted deaths per 10,000 clients.DiscussionWhile there is some additional short-term risk of SARS-CoV-2 transmission associated with providing HIV services, the risk of additional COVID-19 deaths is at least 100 times less than the HIV deaths averted by those services. Ministries of Health need to take into account many factors in deciding when and how to offer essential health services during the COVID-19 pandemic. This work shows that the benefits of continuing key HIV services are far larger than the risks of additional SARS-CoV-2 transmission.

Assessment and design of real world driving cycles targeted to the calibration of vehicles with electrified powertrain

2021 ◽  
pp. 146808742110387
Author(s):  
Stylianos Doulgeris ◽  
Zisimos Toumasatos ◽  
Maria Vittoria Prati ◽  
Carlo Beatrice ◽  
Zissis Samaras
Keyword(s):  
Real World ◽  
Simulation Models ◽  
Cost Effective ◽  
Operational Parameters ◽  
Virtual Design ◽  
Passenger Cars ◽  
Real World Data ◽  
Vehicle Simulation ◽  
Driving Cycles ◽  
The Impact

Vehicles’ powertrain electrification is one of the key measures adopted by manufacturers in order to develop low emissions vehicles and reduce the CO2 emissions from passenger cars. High complexity of electrified powertrains increases the demand of cost-effective tools that can be used during the design of such powertrain architectures. Objective of the study is the proposal of a series of real-world velocity profiles that can be used during virtual design. To that aim, using three state of the art plug-in hybrid vehicles, a combined experimental, and simulation approach is followed to derive generic real-world cycles that can be used for the evaluation of the overall energy efficiency of electrified powertrains. The vehicles were tested under standard real driving emissions routes, real-world routes with reversed order (compared to a standard real driving emissions route) of urban, rural, motorway, and routes with high slope variation. To enhance the experimental activities, additional virtual mission profiles simulated using vehicle simulation models. Outcome of the study consists of specific driving cycles, designed based on standard real-world route, and a methodology for real-world data analysis and evaluation, along with the results from the assessment of the impact of different operational parameters on the total electrified powertrain.

Behavior Selection Using Utility-Based Reinforcement Learning in Irregular Warfare Simulation Models

2013 ◽  
Vol 4 (3) ◽  
pp. 61-78 ◽  
Author(s):  
Sotiris Papadopoulos ◽  
Francisco Baez ◽  
Jonathan Alt ◽  
Christian Darken
Keyword(s):  
Reinforcement Learning ◽  
Adaptive Learning ◽  
Simulation Models ◽  
The Body ◽  
Irregular Warfare ◽  
Agent Based ◽  
Body Of Knowledge ◽  
Learning Techniques ◽  
Study Results ◽  
The Impact

The Theory of Planned Behavior (TPB) provides a conceptual model for use in assessing behavioral intentions of humans. Agent based social simulations seek to represent the behavior of individuals in societies in order to understand the impact of a variety of interventions on the population in a given area. Previous work has described the implementation of the TPB in agent based social simulation using Bayesian networks. This paper describes the implementation of the TPB using novel learning techniques related to reinforcement learning. This paper provides case study results from an agent based simulation for behavior related to commodity consumption. Initial results demonstrate behavior more closely related to observable human behavior. This work contributes to the body of knowledge on adaptive learning behavior in agent based simulations.

3-D Data Processing to Extract Vehicle Trajectories from Roadside LiDAR Data

2018 ◽  
Vol 2672 (45) ◽  
pp. 14-22 ◽  
Author(s):  
Yuan Sun ◽  
Hao Xu ◽  
Jianqing Wu ◽  
Jianying Zheng ◽  
Kurt M. Dietrich
Keyword(s):  
High Resolution ◽  
Data Processing ◽  
Extraction Procedure ◽  
Estimation Method ◽  
Connected Vehicle ◽  
Vehicle Trajectories ◽  
Vehicle Data ◽  
Stop Sign ◽  
Processing Procedure ◽  
Data Processing Procedure

High-resolution vehicle data including location, speed, and direction is significant for new transportation systems, such as connected-vehicle applications, micro-level traffic performance evaluation, and adaptive traffic control. This research developed a data processing procedure for detection and tracking of multi-lane multi-vehicle trajectories with a roadside light detection and ranging (LiDAR) sensor. Different from existing methods for vehicle onboard sensing systems, this procedure was developed specifically to extract high-resolution vehicle trajectories from roadside LiDAR sensors. This procedure includes preprocessing of the raw data, statistical outlier removal, a Least Median of Squares based ground estimation method to accurately remove the ground points, vehicle data clouds clustering, a principle component-based oriented bounding box method to estimate the location of the vehicle, and a geometrically-based tracking algorithm. The developed procedure has been applied to a two-way-stop-sign intersection and an arterial road in Reno, Nevada. The data extraction procedure has been validated by comparing tracking results and speeds logged from a testing vehicle through the on-board diagnostics interface. This data processing procedure could be applied to extract high-resolution trajectories of connected and unconnected vehicles for connected-vehicle applications, and the data will be valuable to practices in traffic safety, traffic mobility, and fuel efficiency estimation.

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