scholarly journals VMT-Mix Modeling for Mobile Source Emissions Forecasting: Formulation and Empirical Application

Author(s):  
Chandra R. Bhat ◽  
Harikesh S. Nair

A fractional split model is proposed and implemented that predicts the vehicle miles traveled (VMT) mix on links as a function of the functional roadway classification of the link, the physical attributes of the link, the operating conditions on the link, and the attributes of the traffic analysis zone in which the link lies. The fractional split model is a useful formulation for VMT-mix analysis because it accommodates boundary values of fractional VMT in a vehicle class, is easy to estimate using commonly available econometric software, and is easy to apply in forecasting mode to predict the VMT mix on each link of a network. The empirical analysis applies the fraction split model structure to estimate a VMT-mix model for the Dallas–Fort Worth metropolitan region in Texas. The results of model evaluation also are presented.

Author(s):  
Daivamani Sivasailam ◽  
Jon Williams

States and metropolitan areas are under increasing pressure to implement transportation control measures (TCMs) to reduce mobile source emissions. Many of these TCMs are aimed at commute trips (i.e., trips from home to work and back). A number of techniques are used to analyze the TCMs. Models use home-based work (HBW) trip tables as input; these consist of the trip from home to work and the trip from work to home, which account for 25 to 30 percent of all trips in a region. However, analysis of the Home Interview Survey data for Washington, D.C., indicates a large number of the nonwork trips were actually taking place either as part of the trip from home to work or from work to home, or during the workday. If a TCM is analyzed using only the HBW trip table, it is implicitly assumed that there will be no impact on the trip from home to work with an intermediate stop. However, it is possible that the TCM could alter the behavior of the person making the home-to-work trip with an intermediate stop. If this is not accounted for, the results of the analysis underestimate the impact of the TCM. Research undertaken for two distinct but related subjects is summarized. The amount of work-related nonwork travel in the Washington, D.C., metropolitan region is estimated, and the methodology developed to account for the effect of TCMs on total work is described.


Author(s):  
Tom Kear ◽  
Deb Niemeier

In the California Air Resources Board’s newest model of mobile-source emissions, EMFAC 2002, vehicle population and mileage accrual data have been revised such that regional vehicle miles traveled (VMT) are calculated from vehicle population and accrual data [rather than directly, using metropolitan planning organization (MPO) estimates]. Calculated VMT is forced to match the MPO VMT estimate by scaling the mileage accrual rates and altering vehicle population data. Vehicle population and mileage accrual data also determine how VMT is allocated across the vehicle model years present in the vehicle fleet; thus, modification of these data also changes the fraction of the VMT associated with each model year in the vehicle fleet. Composite emissions rates were estimated based on various vehicle population and mileage accrual data. Small perturbations in age distributions and accrual data have a larger-than-expected impact on the composite emissions rates for light-duty automobiles. For example, total organic gas emissions varied by nearly a factor of 3 between the lowest and highest estimated emissions rates, and either emissions rate could justifiably be used in an inventory. Recommendations for VMT and accrual data in subsequent release of EMFAC 2002 are provided, giving preference to the methods used by the U.S. Environmental Protection Agency.


Author(s):  
William Bachman ◽  
Wayne Sarasua ◽  
Randall Guensler

Because vehicle activities and the emissions associated with them can be correlated with specific points in time and space, the modeling capabilities of a geographic information system (GIS) are well suited to the modeling of mobile-source emissions. A GIS-based modeling approach can provide emissions estimates for both on-network and off-network vehicle activities on a modal basis (as a function of various vehicle operating modes that significantly affect vehicle emission rates). An entire metropolitan region can be modeled on a zone, link, and point basis. Vehicle subfleet composition can be tracked or estimated and combined with estimates of vehicle activity and characteristic operating modes to provide emissions estimates in a spatial and temporal context. Emissions from various modal activities are aggregated into grid cells to be used as input to an airshed model. Identifying spatial and temporal distributions of these activities adds to a greater understanding of emissions impacts. A research prototype of this modeling concept was produced to illustrate its capabilities and identify difficulties that must be addressed in the development of a fully functional model. The GIS-based displays and hard-copy maps that present the spatial variability of emissions levels help improve the communication of research findings to decision makers and the public. The effort being undertaken at Georgia Institute of Technology in conjunction with the Environmental Protection Agency to develop a next-generation modal emissions model within a GIS framework is described.


Author(s):  
Simona Babiceanu ◽  
Sanhita Lahiri ◽  
Mena Lockwood

This study uses a suite of performance measures that was developed by taking into consideration various aspects of congestion and reliability, to assess impacts of safety projects on congestion. Safety projects are necessary to help move Virginia’s roadways toward safer operation, but can contribute to congestion and unreliability during execution, and can affect operations after execution. However, safety projects are assessed primarily for safety improvements, not for congestion. This study identifies an appropriate suite of measures, and quantifies and compares the congestion and reliability impacts of safety projects on roadways for the periods before, during, and after project execution. The paper presents the performance measures, examines their sensitivity based on operating conditions, defines thresholds for congestion and reliability, and demonstrates the measures using a set of Virginia safety projects. The data set consists of 10 projects totalling 92 mi and more than 1M data points. The study found that, overall, safety projects tended to have a positive impact on congestion and reliability after completion, and the congestion variability measures were sensitive to the threshold of reliability. The study concludes with practical recommendations for primary measures that may be used to measure overall impacts of safety projects: percent vehicle miles traveled (VMT) reliable with a customized threshold for Virginia; percent VMT delayed; and time to travel 10 mi. However, caution should be used when applying the results directly to other situations, because of the limited number of projects used in the study.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Atie Rachmiatie ◽  
Fitri Rahmafitria ◽  
Karim Suryadi ◽  
Ajeng Ramadhita Larasati

Purpose The research aims to classify halal hotels based on Islamic values as embodied in both physical and non-physical attributes. Design/methodology/approach This study explores the perceived values of business owners of the halal hotels. Findings Perceptions of hotel owners are divided into three types: those who view the value of halal hotel only in terms of branding and attracting consumers; those who consider the ideology behind halal hotels based on strong Islamic values; and those who avoid halal branding but implement Islamic values in their hotels. For the hotel industry, halal certification is not a priority because a minimum effort at implementing halal standards can already attract Muslim customers. This case is especially true for countries where Muslims make up the majority of the population. Research limitations/implications This study was limited to a case study in Bandung and Bangkok as a representative of halal tourism in Asia. Hence, it could be extended by conducting comparative studies with other cities in Association of South East Asian Nation which already declare to develop halal tourism. Practical implications The findings of this research show that there is a large variety of halal hotel products, depending on the Islamic values upheld, which is causing difficulties for the government in creating standards. Then the result can help inform the government in establishing the strategic framework of halal tourism development, more particularly in the formulation of policy for industrial actors. Originality/value The findings contribute to the concept of product-centered business, in which it is generally assumed that industrial actors are frequently focused on the mere label of “halal” and ignore the true values. However, the research shows that some industrial actors put Islamic values first instead of the mere halal label, and another case shows that some of them implement Islamic values in their business but avoid halal branding. This empirical evidence shows that in halal hotels, the concept of product-centered is not always proper. The quality of halal hotel products depends on the Islamic value of the owner, not always influenced by business imperatives.


1999 ◽  
Vol 10 (3) ◽  
pp. 203-208 ◽  
Author(s):  
I.C.B. Campos ◽  
A.S. Pimentel ◽  
S.M. Corrêa ◽  
G. Arbilla

Author(s):  
Y. A. Sekretarev ◽  
D. A. Menyaikin

Reliability of power supply of consumers is an important task in the process of transmission and distribution of electric energy. The paper proposes a method for assessing the consequences of power failures of monoconsumers of electric energy on the example of an oil company and an adjacent power grid company. The uniqueness of the developed technique lies in the possibility of reliable calculation of reliability of power supply of complex branched electric networks without taking into account the specific scheme of power supply. The accuracy of calculations is increased due to the use of data directly studied power system, taking into account the specifics and operating conditions of specific equipment, instead of the average information. Classification of failures on the main reasons in electric networks of the oilproducing enterprise of the far North that allowed to develop actions for increase of level of reliability of power supply is made.


2021 ◽  
Vol 11 (4) ◽  
pp. 557-567
Author(s):  
A.A. Dobrodeev ◽  
◽  
K.E. Sazonov ◽  

In the modern world, it is already difficult to imagine the creation of a significant engineering structure without modeling its external and internal appearance, the operation modeling of the main mechanisms, operating conditions and many other design features and emerging phenomena at the design stage. The paper interprets modeling and simulation as one of the computational methods that allow us to obtain quantitative results when studying ice impact on marine structures, for e.g. icebreakers and transport vessels, platform substructures, hydro-technical installations. In connection with the above, from the existing classification of modeling methods, the authors consider the physical and mathematical ones in the work. They present comparative advantages of both methods in their application in the problems of marine ice engineering, as well as the prospects for their development for solving a wide range of scientific problems aimed at the development of Arctic shipbuilding.


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