Calibration of Vissim Models for Rural Freeway Lane Closures: Novel Approach to the Modification of Key Parameters

2019 ◽  
Vol 2673 (5) ◽  
pp. 574-583 ◽  
Author(s):  
Nicholas L. Jehn ◽  
Rod E. Turochy
Keyword(s):  
Traffic Flow ◽  
Discharge Rate ◽  
The United States ◽  
Simulation Software ◽  
Work Zone ◽  
Analysis Tool ◽  
Time Headway ◽  
Novel Approach ◽  
Microsimulation Models ◽  
Lane Closures

The definition of freeway work zone capacity has been a topic of debate for several decades, leaving agencies with limited guidance on predicting the behavior of traffic flow at given volumes for various work zone configurations. The methodology presented in the recently published 6th edition of the Highway Capacity Manual (HCM) is a substantial improvement over historical guidance and provides estimates of the mean queue discharge rate under a variety of prevailing site conditions. However, it is limited by the fact that its outputs are deterministic, while traffic flow and breakdown are stochastic phenomena. Recently, well-calibrated microsimulation models have shown promise as a freeway work zone traffic analysis tool, but most guidance is focused on site-specific modeling. This research aimed to address these shortcomings by presenting a novel approach to developing and calibrating generalizable microsimulation models for rural freeway lane closures in Vissim, a traffic simulation software package developed by the PTV Group. Specifically, it was determined that such models may best replicate field conditions at rural freeway work zones when time headway is described by a field-measured distribution and truck characteristics are representative of the United States (U.S.) fleet. The results suggested that the default desired acceleration for heavy trucks should be set between 2 and 3 ft/s2 and that separate time headway distributions should be constructed for passenger cars and trucks. The methodology presented herein may be extended to obtain stochastic estimates of capacity for sites exhibiting a variety of geometric, traffic, and environmental characteristics.

Development of Breakdown Probability Models and Heavy Vehicle Passenger Car Equivalents for Rural Freeway Work Zones

2020 ◽  
Vol 2674 (12) ◽  
pp. 144-154
Author(s):  
Nicholas L. Jehn ◽  
Rod E. Turochy
Keyword(s):  
Discharge Rate ◽  
Risk Tolerance ◽  
Work Zone ◽  
Work Zones ◽  
Probability Models ◽  
Passenger Car ◽  
Breakdown Probability ◽  
Freeway Work Zones ◽  
The Impact ◽  
Lane Closures

With nearly nine million lane-miles of public roadway and an economy driven by the automobile, interruptions to normal traffic operations for construction and maintenance are inevitable in the U.S.A., but the substantial safety and mobility impacts associated with queueing at freeway lane closures are mitigable. The current freeway work zone capacity methodology in the 6th edition of the Highway Capacity Manual is a vast improvement over historical guidance but still approaches the issue differently than research suggests agencies and practitioners should. Namely, a capacity defined by the mean queue discharge rate is deterministic and fails to account for the stochastic nature of traffic flow and breakdown. These core issues were addressed in this research by developing a methodology for obtaining probabilistic estimates of rural freeway work zone capacity from simulated data in PTV Vissim. Results for a two-to-one lane closure were presented as a series of breakdown probability distributions to demonstrate the viability of this methodology. The data indicated that the impact of trucks on freeway capacity is exacerbated in the presence of lane closures and led to the development of work zone capacity-based passenger car equivalents. Such a procedure may be extended to freeway facilities exhibiting different geometric, traffic, and environmental characteristics and utilized by agencies to make data-driven, risk tolerance-based planning, design, and operations decisions at freeway work zones.

Survey of Work Zone Practices and Validation of Highway Capacity Manual Work Zone Capacity Model

2021 ◽  
pp. 036119812110145
Author(s):  
Raju Thapa ◽  
Julius Codjoe ◽  
Amanua Osafo
Keyword(s):  
The United States ◽  
The State ◽  
Work Zone ◽  
Work Zones ◽  
Highway Capacity ◽  
Local Data ◽  
Highway Capacity Manual ◽  
Capacity Model ◽  
Minimum Capacity ◽  
Lane Closures

Capacity at work zones is one of the major factors affecting queueing at work zones. Different states within the United States use their own methodology in determining work zone capacities and when to implement lane closures at work zones. The objective of this study was two-fold: first, to provide a synthesis of work zone lane closure procedures practiced by the various Departments of Transportation (DOTs) nationwide; and secondly, to validate the Highway Capacity Manual 6th edition’s (HCM 6) work zone capacity model using field-collected data in the state of Louisiana. The first objective was met by administering a survey to DOTs nationwide. The survey revealed that half of the states that responded to the survey require minimum capacity for short-term work zone lane closures, with minimum capacity ranging from 1100 to 1900 passenger cars per hour per lane. In addition, most of the states reported implementing consistent policies across various district offices. The survey findings provide a good source of information on queue analysis and work zone lane closure policies adopted across different DOTs. The second objective was met by collecting traffic flow data from 10 work zone sites within the state of Louisiana and validating the capacity model in the HCM 6. Results showed the HCM 6 model slightly overestimating the average field-observed capacity by 6%. In the absence of local data, the HCM 6 model provides a great tool to estimate work zone capacities in Louisiana.

Forecasting Interconnections in International Housing Markets: Evidence from the Dynamic Model Averaging Approach

2020 ◽  
Vol 42 (1) ◽  
pp. 37-103
Author(s):  
Hardik A. Marfatia
Keyword(s):  
Dynamic Model ◽  
Model Averaging ◽  
Housing Markets ◽  
The United States ◽  
Forecasting Model ◽  
Change Over Time ◽  
The United Kingdom ◽  
Novel Approach ◽  
Dynamic Model Averaging ◽  
Over Time

In this paper, I undertake a novel approach to uncover the forecasting interconnections in the international housing markets. Using a dynamic model averaging framework that allows both the coefficients and the entire forecasting model to dynamically change over time, I uncover the intertwined forecasting relationships in 23 leading international housing markets. The evidence suggests significant forecasting interconnections in these markets. However, no country holds a constant forecasting advantage, including the United States and the United Kingdom, although the U.S. housing market's predictive power has increased over time. Evidence also suggests that allowing the forecasting model to change is more important than allowing the coefficients to change over time.

scholarly journals Orexin receptor antagonists reverse aberrant dopamine neuron activity and related behaviors in a rodent model of stress-induced psychosis

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hannah B. Elam ◽  
Stephanie M. Perez ◽  
Jennifer J. Donegan ◽  
Daniel J. Lodge
Keyword(s):  
United States ◽  
Sensorimotor Gating ◽  
The United States ◽  
Dopamine Neuron ◽  
Neuron Activity ◽  
Sprague Dawley ◽  
Post Traumatic Stress ◽  
Neuron Population ◽  
Population Activity ◽  
Novel Approach

AbstractPost-traumatic stress disorder (PTSD) is a prevalent condition affecting approximately 8% of the United States population and 20% of United States combat veterans. In addition to core symptoms of the disorder, up to 64% of individuals diagnosed with PTSD experience comorbid psychosis. Previous research has demonstrated a positive correlation between symptoms of psychosis and increases in dopamine transmission. We have recently demonstrated projections from the paraventricular nucleus of the thalamus (PVT) to the nucleus accumbens (NAc) can regulate dopamine neuron activity in the ventral tegmental area (VTA). Specifically, inactivation of the PVT leads to a reversal of aberrant dopamine system function and psychosis-like behavior. The PVT receives dense innervation from orexin containing neurons, therefore, targeting orexin receptors may be a novel approach to restore dopamine neuron activity and alleviate PTSD-associated psychosis. In this study, we induced stress-related pathophysiology in male Sprague Dawley rats using an inescapable foot-shock procedure. We observed a significant increase in VTA dopamine neuron population activity, deficits in sensorimotor gating, and hyperresponsivity to psychomotor stimulants. Administration of selective orexin 1 receptor (OX1R) and orexin 2 receptor (OX2R) antagonists (SB334867 and EMPA, respectively) or the FDA-approved, dual-orexin receptor antagonist, Suvorexant, were found to reverse stress-induced increases in dopamine neuron population activity. However, only Suvorexant and SB334867 were able to reverse deficits in behavioral corelates of psychosis. These results suggest that the orexin system may be a novel pharmacological target for the treatment of comorbid psychosis related to PTSD.

scholarly journals The use of simulation modelling for determining the capacity of railway lines in the Czech conditions

2020 ◽  
Vol 10 (1) ◽  
pp. 224-231
Author(s):  
Erik Tischer ◽  
Petr Nachtigall ◽  
Jaromír Široký
Keyword(s):  
Czech Republic ◽  
Traffic Flow ◽  
Software Tool ◽  
Simulation Modelling ◽  
Energy Performance ◽  
Simulation Software ◽  
The Czech Republic ◽  
Railway Line ◽  
Specialized Software ◽  
Railway Infrastructure

AbstractSimulation modelling is one way to determine the capacity of railway lines. The specialized software tool OpenTrack was used for simulation. The aim of this paper was to find out whether the OpenTrack simulation software can be used for the calculation of headway, and to compare the results with the methodology of the Railway Infrastructure Administration (SŽDC). Using the software tool, a detailed transport network model can be created including all its important characteristics. The simulation follows the movements and behaviour of trains with predefined parameters on the modelled railway line. OpenTrack allows for monitoring a range of parameters including not only train delays, train conflicts and train traffic flow, but also for instance train energy performance and headways. During the first stage of work with OpenTrack, a simulation model was created, not reflecting any existing infrastructure but including parameters typical of railway lines in the Czech Republic, such as the configuration of gridirons, length of station tracks, size of block sections, etc. This model was subsequently used for the simulation of type train set journeys, and a headway calculator was used for the calculation of headway values. These values were compared with the methodology used by the Railway Infrastructure Administration. The paper is concluded by the comparison of the above mentioned approaches.

scholarly journals Use of Dynamic Analysis to Investigate the Behaviour of Short Neutral Sections in the Overhead Line Electrification

2021 ◽  
Vol 6 (5) ◽  
pp. 62
Author(s):  
John Morris ◽  
Mark Robinson ◽  
Roberto Palacin
Keyword(s):  
Dynamic Analysis ◽  
Dynamic Simulation ◽  
Model Simulation ◽  
Analysis Tool ◽  
Overhead Line ◽  
Element Analysis ◽  
Novel Approach ◽  
Section Model ◽  
The Uk ◽  
Neutral Section

The ‘short’ neutral section is a feature of alternating current (AC) railway overhead line electrification that is often unreliable and a source of train delays. However hardly any dynamic analysis of its behaviour has been undertaken. This paper briefly describes the work undertaken investigating the possibility of modelling the behaviour using a novel approach. The potential for thus improving the performance of short neutral sections is evaluated, with particular reference to the UK situation. The analysis fundamentally used dynamic simulation of the pantograph and overhead contact line (OCL) interface, implemented using a proprietary finite element analysis tool. The neutral section model was constructed using physical characteristics and laboratory tests data, and was included in a validated pantograph/OCL simulation model. Simulation output of the neutral section behaviour has been validated satisfactorily against real line test data. Using this method the sensitivity of the neutral section performance in relation to particular parameters of its construction was examined. A limited number of parameter adjustments were studied, seeking potential improvements. One such improvement identified involved the additional inclusion of a lever arm at the trailing end of the neutral section. A novel application of pantograph/OCL dynamic simulation to modelling neutral section behaviour has been shown to be useful in assessing the modification of neutral section parameters.

scholarly journals Performance and style in the work of Olgyay and Olgyay

2014 ◽  
Vol 18 (2) ◽  
pp. 167-176 ◽  
Author(s):  
David Leatherbarrow ◽  
Richard Wesley
Keyword(s):  
Graphical Representation ◽  
Building Design ◽  
The United States ◽  
Energy Performance ◽  
Control Device ◽  
Simulation Software ◽  
Open Architecture ◽  
Form Generation ◽  
The Difference ◽  
Building Energy Analysis

The sun control device has to be on the outside of the building, an element of the facade, an element of architecture. And because this device is so important a part of our open architecture, it may develop into as characteristic a form as the Doric column.Victor Olgyay (1910–1970), a Hungarian architect who came to the United States in 1947 with his twin brother and collaborator, Aladár (1910–1963), is best known today as the author of Design with Climate: Bioclimatic Approach to Architectural Regionalism (1963), an important book often referenced in the environmental building design field [1]. As leaders in research in bioclimatic architecture from the early 1950s to the late 1960s, the Olgyay brothers could be considered the ‘fathers’ of contemporary environmental building design. Their research and publications laid the foundation for much of the building simulation software in use today. Other than the difference between working on graph paper and using computer-generated graphics, there is little difference between Autodesk's Ecotect Analysis (simulation and building energy analysis software) and the Olgyays' techniques for the analysis of environmental factors and graphical representation of climate. The manner in which the Olgyays established connections between building design and the science of climate laid the foundation for the development of environmental simulation, one of contemporary architecture's leading methods of form generation. Victor Olgyay's teaching, however, represents another kind of thinking, a broader concern for architecture, beyond energy performance. ‘The primary task of architecture,’ Olgyay announced to his students, ‘is to act in man's favour; to interpose itself between man and his natural surroundings in order to remove the environmental load from his shoulders.

scholarly journals Pulmonary Embolism Response Teams: A Novel Approach for the Care of Complex Patients With Pulmonary Embolism

2018 ◽  
Vol 24 (9_suppl) ◽  
pp. 48S-55S ◽  
Author(s):  
Mateo Porres–Aguilar ◽  
Javier E. Anaya-Ayala ◽  
Gustavo A. Heresi ◽  
Belinda N. Rivera-Lebron
Keyword(s):  
Pulmonary Embolism ◽  
The United States ◽  
Cardiovascular Death ◽  
Pulmonary Embolectomy ◽  
Systemic Thrombolysis ◽  
Cardiopulmonary Support ◽  
Novel Approach ◽  
Adoption And Implementation ◽  
Complex Patients

Pulmonary embolism represents the third most common cause of cardiovascular death in the United States. Reperfusion therapeutic strategies such as systemic thrombolysis, catheter directed therapies, surgical pulmonary embolectomy, and cardiopulmonary support devices are currently available for patients with high- and intermediate-high–risk pulmonary embolism. However, deciding on optimal therapy may be challenging. Pulmonary embolism response teams have been designed to facilitate multidisciplinary decision-making with the goal to improve quality of care for complex cases with pulmonary embolism. Herein, we discuss the current role and strategies on how to leverage the strengths from pulmonary embolism response teams, its possible worldwide adoption, and implementation to improve survival and change the paradigm in the care of a potentially deadly disease.

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