bluuebunny/crossref_metadata_2025 huggingface dataset:
Geomechanics for the Thermal Stimulation of Heavy Oil Reservoirs–Canadian Experience
Authors: Yuan Yanguang , Xu Bin , Yang Baohong
Published: December 2011

This paper will cover both caprock integrity and reservoir deformation, drawing from our years of experience in working with the heavy oil/oilsands industry in Alberta, Canada. Theoretical principles are described, analytical derivations made and field examples given, all to help illustrate the fundamentals and summarize the learnings in proactive utilization of geomechanics to enhance the reservoir performance and proactive consideration of geomechanics to ensure the caprock integrity. Topics include dilation tendency and fracturing behaviour in the oilsands, major geomechanical work components for the caprock integrity analysis/design, mini-frac tests and nonlinear coupled thermo-hydro-mechanical processes.
Method of Minimizing Liner Expansion Issues in Horizontal Thermal Applications
Authors: Cavender Travis , Hunter Tim , Pipkin Robert
Published: December 2011

Thermal recovery methods used in the exploitation of heavy-oil and bitumen reservoirs can create severe expansion problems on liner and production tubular equipment caused by the effects of thermal expansion. This is more often the case when using horizontal sandface completion configurations in steam flood, cyclic steam, and steam-assisted gravity drainage (SAGD) applications.

Many single lateral and multi-lateral horizontal heavy-oil wells are produced initially using cold ambient reservoir heavy-oil production methodologies where liner expansion is not a concern. However, with proper up-front planning and engineering, these wells could be converted to thermal EOR producers with the addition of thermal expansion devices placed within the liner assembly when initially completed. These expansion devices are engineered to activate when exposed to elevated temperatures once the thermal operations begin and do not require mechanical activation or well intervention. Since these devices are deployed with the liner assembly, they must also be capable of handling compression, tension, and torque loading across the liner during the deployment phase.

These devices can be deployed with the slotted liner/sand screen applications or can be used with production or concentric tubing configurations. This paper will present use of this new device in different wellbore configurations found in various thermal recovery methods.
Viscosity Predictions of Kuwaiti Heavy Crudes at Elevated Temperatures
Authors: Alomair Osamah , Elsharkawy Adel , Alkandari Hassan
Published: December 2011

Viscosity is a key property for evaluation, simulation and development of petroleum reservoirs. The accurate prediction of viscosity will be helpful for, production forecasting, designing future of thermal recovery processes. Reservoir oil viscosity is usually measured isothermally at reservoir temperature. However, at temperature other than reservoir temperature these data are estimated by empirical correlations. Here, based on results of viscosity measurements of 33 heavy crude oil samples of API gravity ranging from 10° and 20° degree, at 68 °F collected from various areas of Kuwaiti oil fields, and tested at 68 to 320 °F. A new correlation has been developed. The validity and accuracy of this correlation has been confirmed by comparing the obtained results of this correlation with other ones along-with the experimental data. The result were satisfactory, in contrast to other correlations which were mostly developed for significantly lighter oils at average reservoir temperatures. Most of them cannot reasonably predict the heavy oil viscosity at elevated temperatures.
Comparative Analysis of Electromagnetic Methods for Heavy Oil Recovery
Authors: Bogdanov Igor , Torres Jose Antonio , Kamp Arjan , Corre Bernard
Published: December 2011

Energy producing companies increasingly exploit non-conventional hydrocarbon resources such as heavy oil, bitumen or shale. Because of their large viscosity, production of oil from such resources is frequently done through reservoir heating, most often via steam injection. In some cases the steam injection is not a good alternative, especially, for tar sands. A better suited technology may be electromagnetic heating (EMH) assisted oil recovery.

Different physical mechanisms underlie the heating according to the frequency of electromagnetic (EM) field. For instance, low-frequency heating (LFH) based on the Joule effect is well-known for environmental applications and has been field-tried recently. So-called inductive heating used for many years in induction furnaces is the process where Foucault (eddy) currents generated within a load result again in Joule heating. Finally, high-frequency heating (HFH) consists of in-situ dielectric heating resulted from rotation with friction of polar molecules in the EM field.

An EM field facility is installed normally in a well bore, the EM power being converted into heat inside reservoir which leads to the increase of local temperature. The conspicuous advantages of all EMH methods – avoidance of well low injectivity/connectivity and well injection pressure related problems – are complemented with in-situ heat generation and particularly, water evaporation (e.g. during HFH). Nowadays, according to literature sources, the EMH models of two types are in use. The first one is a class of analytical approaches using relatively strong assumptions mainly concerning to heating power distribution. They provided reference solutions for numerical models and an order-of-magnitude estimation procedure which is feasible for large-scale models.

Being geometrically more complex the large-scale models have been developed for simulation of more realistic EM power distribution. These models provided a framework to critically analyze the processes of oil recovery. The obtained numerical results are used for subsequent consideration of advantages and application limits for each of considered EMH methods, i.e. for low- and radio-frequency heating assisted heavy oil recovery.

The comparative analysis of different methods of EMH assisted oil production provided by this work is an important feature in process design considerations.
Optimal Voidage Replacement Ratio for Communicating Heavy Oil Waterflood Wells
Authors: Vittoratos E. Steven , Coates R. , West C. C.
Published: December 2011

Accumulated field empirical observations suggest that water injected to displace heavy oils forms in the reservoir channel-like communication paths from the injectors to the producers. The evidence comes from mass balances and, more recently, from 4D seismic monitoring of heavy oil waterfloods. The reasons for this are multifold, including unconsolidated sand formation dilation about injectors due to slow pressure diffusion in heavy oils, reservoir heterogeneities in permeability and saturation, sand production from the reservoir, and the instability of the displacement interface due to the high mobility ratio between water and heavy oil. Once formed, the channels can degrade further economic recovery of the heavy oil as the water oil ratios increase significantly. This study reports on initial results from a laboratory program to test the optimal reservoir management response upon formation of such communication paths in heavy oil waterfloods.

To physically simulate reservoir waterflood behavior under the existence of a communication path, a large scale ‘big can’, five feet long with a ten inch by ten inch cross section, was designed and constructed that allowed for the creation of a highly reproducible communication path from the injection to production end of the can. This was a mandatory requirement for accurate comparison between alternative reservoir management strategies whose differences would otherwise be hidden by variations in random communication path formation. The design has proven to be highly successful. Our first objective was to test whether the industry paradigm and the regulatory mandated practice of maintaining a voidage replacement ratio (VRR) of one throughout the entire waterflood is optimal. Live 18.6 API Alaska North slope oil was used to saturate four Darcy sand that filled the big can. Upon creation of the communication path, three VRRs were tested: 1.0 (conventional waterflood), 0.7 (hybrid waterflood/solution gas drive), and 0.0 (conventional solution gas drive). The VRR=0.7 run outperformed the conventional VRR=1.0, suggesting that periods of under injection may improve heavy oil waterflood response upon formation of injector-producer communication.
Probabilistic Forecasting and Model Validation for the 1st Eocene Large Scale Pilot (LSP) Steamflood, Partitioned Zone (PZ), Saudi Arabia and Kuwait
Authors: Osterloh W. Terry , Mims Don S. , Meddaugh W. Scott
Published: December 2011

The 1st Eocene heavy oil reservoir (1E) in the Wafra field is a candidate for steamflooding due to its world-class resource base and low estimated primary recovery. However, industry has little experience in steamflooding carbonate reservoirs, which has prompted staging of several 1E steamflood tests, the latest of which is the Large Scale Pilot (LSP) started in 2009. To assist in facilities design, help understand expected performance in a very heterogeneous reservoir, and provide input to early decision analyses, numerical thermal simulation was used to generate probabilistic forecasts. Once adequate pilot history was available, the model was validated using probabilistic methods.

The LSP model was comprised of 1.5 MM cells, which allowed maintenance of adequate resolution and proper boundary conditions in the pilot area. Parallel computation enabled a probabilistic workflow to be implemented with this large thermal model.

In this paper we highlight the methodologies and inputs used to generate the probabilistic forecasts and validate the model. Major results of this work include the following: 1) in contrast to many green-field forecasts that are often optimistic, the LSP forecasts were instead conservative, likely due to unique aspects of the forecasting methodology, proper selection of uncertainty ranges, and the relatively high density of input data for model construction, 2) wide variations in production metrics were forecast, indicative of a highly heterogeneous reservoir, and 3) despite this heterogeneity, oil recovery mechanisms and recovery levels were comparable to those observed in steamfloods in sandstone reservoirs.
High Performance Drilling Fluids Addressing the Challenges in Drilling Shallow Viscous Oil Reservoir in Kuwait
Authors: El Khateeb Samir , Ahmed Khaled , Sotomayor Ghery , Hussein Ahmed
Published: December 2011

The primary challenge in drilling shallow depth viscous oil formation in Kuwait is to achieve gauged holes while drilling in unconsolidated friable sand-shale alteration. Gauged holes are the key for the production techniques used in this field, where cement channeling and perforation effectiveness are of main concern. To achieve this, a specific drilling fluid design was necessary. Laboratory tests and extensive research were initiated to customize the drilling fluid parameters and wellbore hydraulics necessary to achieve the primary drilling objectives.

The drilling fluid design goal was to provide enhanced clay inhibition for the clay strikes, gave good lubricity and low friction coefficient to ensure the smooth drilling and tripping operations in a gauged hole profile. Additionally, the environmental advantage of avoiding the generation of drilling waste with high chloride content was achieved, therefore contributing to KOC’s HS&E goals.

Fluids viscosity and hydraulics were designed in high profile to remain completely in laminar flow while drilling to minimize washout occurrence and maximize hole cleaning at low circulation rates (140 – 150 GPM) without the use of regular sweeps. The customized drilling parameters and practices, in addition to the knowledge gained from the laboratory testing phase, were transferred to the field. This resulted in proved success with more than hundred and twenty five perfect gauge holes
The Well-Wormhole Model of Cold Production of Heavy Oil Reservoirs
Authors: Istchenko C. M. , Gates I. D.
Published: December 2011

Cold Heavy Oil Production with Sand (CHOPS) is a non-thermal heavy oil recovery technique used primarily in the heavy oil belt in eastern Alberta and western Saskatchewan. Under CHOPS, typical recovery factors are between 5 and 15% with the average being under 10%. This leaves approximately 90% of the oil in the ground after the process becomes uneconomic, making CHOPS wells and fields, prime candidates for EOR and field optimization. CHOPS wells show an enhancement in production rates compared to conventional primary production, which is explained by the formation of high permeability channels known as wormholes. The formation of wormholes has been shown to exist in laboratory experiments as well as field experiments conducted with fluorescein dyes.

The major mechanisms for CHOPS production are foamy oil flow, sand failure and sand production. Foamy oil flow aids in mobilizing sand and reservoir fluids leading to the formation of wormholes. Foamy oil behaviour cannot be effectively modeled by conventional PVT behaviour, leading to the use of a kinetic model, which can be easily implemented with the kinetic reaction features in CMG STARS. The sand is mobilized due to sand failure, determined by a minimum fluidization velocity. The individual wormholes will be modeled in CMG STARS using existing wellbore features. The ability to grow a wellbore dynamically is not built into STARS, leading to the creation of a Dynamic Wellbore Module. The module continuously restarts the STARS simulation runs and determines the growth criteria for wormhole growth. If the criterion is met, the wormhole is grown in the appropriate direction; otherwise the simulation is run again until the criterion is met.

The proposed model incorporates the major factors in CHOPS production and shows an adequate to fit to model general production trends of typical CHOPS well. The model demonstrates there is a criterion for which wormhole growth occurs as wells as limits its extent of growth in a reservoir. The model can then be used for follow-up EOR processes such as cycle solvent injection as well as field optimization.
The Characterization of Heavy Oil Reservoirs Using Downhole Fluid Analysis to Determine Fluid Type and Reservoir Connectivity
Authors: Tsiklakov A. , Weinheber P. , Wichers W. , Zimin S. , Driller A. , Oshmarin R.
Published: December 2011

The Vankor oilfield in Eastern Siberia is characterized by multiple layers of varying types of hydrocarbons, including oils ranging in viscosity from less than 1 cp to over 20 cp, the Russian regulatory cut-off for heavy oil. It is important for every reservoir penetration to determine the type of oil encountered and also to make any possible inferences about reservoir connectivity. Wireline formation testers equipped with downhole fluid analysis (DFA) sensors acquiring color and gas-oil ratio data (GOR) are used to determine the hydrocarbon type and fluid property gradients. Then, using the emerging technology of asphaltene gradient modeling and prediction for heavier oils, we are able to help support conclusions of reservoir connectivity.

In this paper we present datasets from wells where we determine the fluid type from DFA data. Additionally, we incorporate color with pressure gradient data to help build reservoir models that predict reservoir connectivity and compartmentalization.
Geomechanical Screening Criteria for Steam Injection Processes in Heavy Oil and Bitumen Reservoirs
Authors: Collins Patrick M.
Published: December 2011

Thermal recovery processes such as CSS (cyclic steam stimulation) and SAGD (steam-assisted gravity drainage) are affected and limited by reservoir geomechanics. This paper provides new thermal recovery screening criteria based on geomechanics. The purpose is to provide a means of screening prospective reservoirs to assess the practicality of using various steam injection recovery processes, and to assess their relative efficiencies in these reservoirs.

The choice of a thermal recovery process is based on the project economics, which are largely determined by the expected behaviour of the recovery process in the reservoir. Typically, geological hydraulic characteristics, such as the vertical permeability and the presence or absence of impediments to vertical flow, will be the deciding factors in the choice of the recovery process.

However, conventional reservoir characteristics are insufficient to determine the probable success of a recovery process. Reservoir geomechanics can have a significant and even dominant effect on the efficacy of recovery processes.

As a result, the same recovery process in reservoirs with identical conventional reservoir properties can have markedly different levels of success due to their differing geomechanical properties. Reservoir simulations and reserves evaluations should consider these differences, given the expected variance in performance in terms of production rates and ultimate recoveries.

Geomechanical screening provides an additional filter by which recovery processes can be assessed, and perhaps eliminated, based on their expected performance in any given reservoir. Furthermore, the valuation of the recoverable reserves of a reservoir is highly dependent on the expected efficiency of a recovery process, and if the geomechanical characteristics limit the efficiency of recovery processes, that should be known when assessing the value of the heavy oil or bitumen resource. This is essential for recovery process selection and operation.
Stability of tetracycline residues in honey
Authors: Cristina Cara , Gabriela-Alina Dumitrel , Mirel Glevitzky , Delia Perju
Published: December 2011

The problem of availability of veterinary medicines to treat honeybees is
discussed extensively worldwide. An uncontrolled administration of
antibiotics may lead to contamination of beehive products and contributes to
the problem of food safety. In this study, the kinetics of tetracycline (TC)
degradation in honey was studied for samples provided by four sideline
beekeepers located in the west region of Romania. The samples of honey were
stored in the dark at room temperature for 30 days and subsamples were
analyzed every 3 days by Elisa method. The results of the study revealed
that the level of tetracycline decreases in time for all honey samples. The
tetracycline degradation follows a first-order kinetic model with reaction
rate constants between 1.2?10-3 - 2?10-3 days-1. The half-life time of
tetracycline in monofloral honeys: acacia and lime was 251 and 232 days
respectively. Tetracycline degradation in polyfloral honey was accelerated
since ?1/2 of TC was 151 days.
Convergence Flaws
Authors: Reilly David
Published: December 2011

SYNOPSIS

The creation of a truly global set of accounting standards is a long-held dream for many. And the U.S. is inching closer to joining in that effort. Yet before signing on, regulators should consider potential flaws in the underpinnings of such a system. Namely that it will likely prove impossible to consistently enforce such rules across national borders. And even if it was, differing national views of the purpose of financial markets would still lead to varied interpretations of rules. In light of this, a global accounting language is likely to end up with some distinctly different national dialects. If so, the cost and effort associated with a U.S. switch to international standards may not be worth it.
The O*NET: A Challenging, Useful Resource for Investigating Auditing and Accounting Work
Authors: Scarlata Audrey N. , Stone Dan N. , Jones Keith T. , Chen Clement C.
Published: December 2011

The Occupational Information Network database (O*NET), a publicly available employment and occupation resource, contains considerable relevant data on accountants' and auditors' work and employment. Created and maintained by the U.S. Department of Labor, the O*NET is organized into six categories; annual updates derived from multiple sources including job analysts, surveys of employers and employees, and labor economists' employment projections. The extensive resources supporting its creation and maintenance have resulted in statistically defensible sampling methods but considerable variability in the validity of O*NET conceptual constructs and measures. Users of the O*NET include scholars, state employment agencies, employers, career counselors, and job seekers. Although we are unaware of current applications of the O*NET in professional accounting, we suggest ten applications. A small body of accounting research uses the O*NET; we suggest additional future research applications. The limitations of the O*NET include overly broad categories of accounting work, issues related to biases and construct validity, and poor organization and ease-of-use. But for scholars with patience and tenacity, the O*NET provides an important publicly available, longitudinal, and cross-sectional resource for investigating accountancy employment and work.
On parabolic Whittaker functions II
Authors: Oblezin Sergey
Published: December 2011

We propose a Givental-type stationary phase integral representation for the restricted Grm,N-Whittaker function, which is expected to describe the (S
1×U
N)-equivariant Gromov-Witten invariants of the Grassmann variety Grm,N. Our key tool is a generalization of the Whittaker model for principal series U(gl
N)-modules, and its realization in the space of functions of totally positive unipotent matrices. In particular, our construction involves a representation theoretic derivation of the Batyrev-Ciocan-Fontanine-Kim-van Straten toric degeneration of Grm,N.
Stereodynamics of chemical reactions: quasi-classical, quantum and mixed quantum-classical theories
Authors: Xu Wenwu , Zhao Guangjiu
Published: December 2011

In this review, some benchmark works by Han and coworkers on the stereodynamics of typical chemical reactions, triatomic reactions H + D2, Cl + H2 and O + H2 and polyatomic reaction Cl+CH4/CD4, are presented by using the quasi-classical, quantum and mixed quantum-classical methods. The product alignment and orientation in these A+BC model reactions are discussed in detail. We have also compared our theoretical results with experimental measurements and demonstrated that our theoretical results are in good agreement with the experimental results. Quasi-classical trajectory (QCT) method ignores some quantum effects like the tunneling effect and zero-point energy. The quantum method will be very time-consuming. Moreover, the mixed quantum-classical method can take into account some quantum effects and hence is expected to be applicable to large systems and widely used in chemical stereodynamics studies.
Growth and EPR properties of KSm(WO4)2 and KEr(WO4)2 single crystals
Authors: Leniec Grzegorz , Skibiński Tomasz , Kaczmarek Slawomir , Iwanowski Przemyslaw , Berkowski Marek
Published: December 2011

Growth conditions and electron paramagnetic resonance investigations of two well oriented KSm(WO4)2 and KEr(WO4)2 single crystals have been presented and discussed. Hyperfine structure of Sm3+ ion was detected and analyzed for angular and temperature dependences. EPR spectra of KEr(WO4)2 and its angular dependence showed the presence of 5 magnetically nonequivalent Er centers in the crystal. A change in the type of magnetic interactions was analyzed using mixed (Gaussian and Lorentzian) fits of the EPR spectra.
Study of the thermal stability of Zerodur glass ceramics suitable for a scanning probe microscope frame
Authors: Číp Ondřej , Šmíd Radek , Čížek Martin , Buchta Zdeněk , Lazar Josef
Published: December 2011

The work presents measurements of the length stability of Zerodur glass ceramic with temperature change. Measurement of this thermal characteristic is necessary for determination of the optimal temperature at which the Zerodur glass ceramic has a coefficient of thermal expansion close to zero. The principle of the measurement is to monitor the length changes using an optical resonator with a cavity mirror spacer made from the Zerodur material to be studied. The resonator is placed inside a vacuum chamber with a temperature control. A tunable laser diode is locked to a certain optical mode of the resonator to monitor the optical frequency of this mode. A beat-note signal from optical mixing between the laser and a stabilized femtosecond frequency comb is detected and processed. The temperature dependence of the glass ceramics was determined and analyzed. The resolution of the length measurement of the experimental set-up is on the order of 0.1 nm.
Characterisation and performance of three promising heterogeneous catalysts in transesterification of palm oil
Authors: Isahak Wan , Ismail Manal , Jahim Jamaliah , Salimon Jumat , Yarmo Mohd
Published: December 2011

In this work, the performance of three heterogeneous catalysts, namely potassium hydroxide/γ-alumina, bulk calcium oxide, and nano-calcium oxide, in comparison with the homogeneous potassium hydroxide was studied in the transesterification of palm oil to produce methyl esters and glycerol. The physical and chemical properties of the heterogeneous catalysts were thoroughly characterised and determined using a number of analytical methods to assess their catalytic activities prior to transesterification. The reaction products were analysed using liquid chromatography and their properties were quantified based on the American Society of Testing and Materials and United State Pharmacopoeia standard methods. At the 65°C reaction temperature, the oil-to-methanol mole ratio of 1: 15, 2.5 h of the reaction time, and catalyst (φ r = 1: 40), potassium hydroxide, potassium hydroxide/γ-alumina, nano-calcium oxide, and bulk calcium oxide gave methyl ester yields of 97 %, 96 %, 94 %, and 90 %, respectively. The impregnation of γ-alumina with potassium hydroxide displayed a catalytic performance comparable with the performance of potassium hydroxide where the former could be physically separated via filtration resulting in a relatively greater purity of products. Other advantages included the longer reusability of the catalyst and more active sites with lower by-product formation.
Impact of Gasoline Prices on Transit Ridership in Washington State
Authors: Stover Victor W. , Bae C.-H. Christine
Published: December 2011

Gasoline prices in the United States have been extremely volatile in recent years and rose to record high levels during the summer of 2008. According to the U.S. Energy Information Administration, the average U.S. gasoline price for the year 2008 was $3.26 a gallon, which was the second highest yearly average in history when adjusted for inflation. Transportation agencies reported changes in travel behavior as a result of the price spike, with transit systems experiencing record ridership and state departments of transportation reporting reductions in traffic volumes. This study examined the impact of changing gasoline prices on transit ridership in Washington State by measuring the price elasticity of demand of ridership with respect to gasoline price. Ordinary least-squares regression was used to model transit ridership for transit agencies in 11 counties in Washington State during 2004 to 2008. The price of gasoline had a statistically significant effect on transit ridership for seven systems studied, with elasticities ranging from 0.09 to 0.47. A panel data model was estimated with data from all 11 agencies to measure the overall impact of gasoline prices on transit ridership in the state. The elasticity from the panel data model was 0.17. Results indicated that transit ridership increased as gasoline prices increased during the study period. The findings were consistent with those from previous studies on the topic.
Effect of Real-Time Transit Information on Dynamic Path Choice of Passengers
Authors: Cats Oded , Koutsopoulos Haris N. , Burghout Wilco , Toledo Tomer
Published: December 2011

Real-time information (RTI) is increasingly being implemented in transit networks worldwide. The evaluation of the effect of RTI requires dynamic modeling of transit operations and of passenger path choices. The authors present a dynamic transit analysis and evaluation tool that represents timetables, operation strategies, RTI, adaptive passenger choices, and traffic dynamics at the network level. Transit path choices are modeled as a sequence of boarding, walking, and alighting decisions that passengers undertake when carrying out their journey. The model was applied to the Metro network area of Stockholm, Sweden, under various operating conditions and information provision scenarios, as a proof of concept. An analysis of results indicated substantial path choice shifts and potential time savings associated with more comprehensive RTI provision and transfer coordination improvements.
Real-Time Ridesharing
Authors: Amey Andrew , Attanucci John , Mishalani Rabi
Published: December 2011

In recent years, an innovative ridesharing service relying heavily on advanced mobile phone technologies known as real-time ridesharing or dynamic ridesharing, has gained popularity in some groups: providers, organizations, and employers. Traditionally, rideshare arrangements between two or more unrelated individuals for commuting purposes have been relatively inflexible, long-term arrangements. Real-time ridesharing attempts to add flexibility to rideshare arrangements by allowing drivers and passengers to arrange occasional shared rides ahead of time or on short notice. The addition of this service innovation presents opportunities to overcome existing rideshare challenges but also leads to new challenges. The overall goal of this study was to provide a foundation for further realtime ridesharing research. The aims of the study were to identify, highlight, and discuss the potential benefits of and obstacles to real-time ridesharing and to point to the next steps to understand better and possibly advance this mode of travel. A definition of real-time ridesharing was given, followed by a comprehensive categorization of challenges hindering greater rideshare participation. The information gathered suggested that rather than being a single challenge to be overcome, the rideshare challenge was a series of economic, behavioral, institutional, and technological obstacles to be addressed. Potential opportunities and obstacles created by real-time innovations were then highlighted. Several recommendations are provided toward next steps to understand further how rideshare participants use real-time services, focusing on the need for multiple, comprehensive trials of real-time rideshare.
Thinking outside the Box to Expand Metropolitan Travel Choices
Authors: DeCorla-Souza Patrick , Berman Wayne , Halkias John
Published: December 2011

The multimodal expressway system is a concept of introducing travel choices for suburban commuters in major metropolitan areas relatively quickly and inexpensively. The entire existing limited-access highway system would provide for free flow of carpool vehicles and buses by temporarily slowing (or stopping) and releasing excess traffic at freeway entrance ramps and on the freeway main line at a series of concentric cordon locations around the core of the metropolitan area. At these locations, travel lanes would be created on the shoulder and restricted to use by buses and high-occupancy vehicles with three or more persons and would allow them to bypass the slower moving metered general-purpose traffic. A multicentered bus rapid transit system would serve commute trips between suburban residential areas and major employment centers. The transit system would be supplemented with a flexible carpooling system. An enhanced version of the concept would introduce variable peak period tolls to encourage further mode shifts, reduce traffic demand, and help pay for system costs. Sketch planning estimates of costs for freeway, transit, and flexible carpooling investments suggested that the capital costs could be self-financed through road-pricing revenues.
Configuration of Innovative Minibus Service in the Lisbon, Portugal, Municipality
Authors: Eiró Tomás , Martínez L. Miguel , Viegas José Manuel
Published: December 2011

The viability of implementing a new alternative intermediate transport mode in the Lisbon, Portugal, metropolitan area was examined. The intention of this new system was to combine the major strengths of both public transport and private vehicles to provide a competitive transport alternative for commuters from low and intermediate density areas, who do not create enough demand to sustain a high-quality public transport service. Conventional public transport systems can provide efficient space and energy consumption, whereas private vehicles have high levels of flexibility and are fast and always available. A comprehensive methodology is presented to encompass the generation of input data of the model on the basis of transport demand data involving spatial-temporal constraints, the possible location of the service stops, and the detailed characterization of the service operation. The global objective of the model is to design a self-sustainable system that would maximize the operator's profit, not one that would satisfy all potential demand. The developed model uses supply parameters obtained through current bus operators in the region. However, the estimated values should be refined before service deployment. This assessment was performed, as an initial test bed for Lisbon and will be expanded to the whole metropolitan area. Results suggest that this service might be significantly profitable to the operator and a good alternative for single private car drivers. Implementation of this system may relieve some congestion during peak periods.
Assessing Options to Enhance Bicycle and Transit Integration
Authors: Krizek Kevin J. , Stonebraker Eric W.
Published: December 2011

Cycling continues to increase in popularity and garner attention for the ability to achieve environmental, health, and congestion-mitigation benefits for communities. Although the growth in both cycling and transit may be in small part attributed to bicycle and transit integration, the growth is difficult to measure. Which of the variety of available strategies for bicycle and transit integration–such as increased bicycle parking at stops, increased bicycle capacity on transit vehicles, and shared bicycle infrastructure–is more cost-effective? Which strategies will yield the highest number of cycle transit users? To fill a void in the literature about integrating bicycling and transit, four common bicycle and transit integration strategies were described and assessed. A framework was developed for evaluating strategies, and a preliminary cost-effectiveness assessment was conducted. Cost-effectiveness comprises costs and cyclists’ preferences for each strategy. Preferences were gathered through stated-preference surveys from focus groups in five case study communities and calculated according to the analytic hierarchy process, a multi-criterion decision-making tool. Transit with a bicycle aboard was most preferred by cyclists, whereas results of the cost-effectiveness measure suggest that enhancing bicycle parking at a transit stop proved most cost-effective when compared with the most common bicycle onboard transit configuration: front-mounted bicycle racks on buses. The limited growth potential for bicycles aboard transit requires consideration of alternatives. The overall importance that cyclists assigned to security suggested considerable room for creative solutions to improve the favorability of the other strategies while addressing some inherent capacity limitations of the most popular strategy: transporting the bicycle with the rider on transit.
Estimating Optimum Timing for Preventive Maintenance Treatment to Mitigate Pavement Roughness
Authors: Haider Syed Waqar , Dwaikat Monther B.
Published: December 2011

The evaluation of pavement preservation interventions is the most important component of a pavement management system. A rational methodology is needed to evaluate pavement preservation alternatives to maximize project- and network-level benefits. A lack of adequate guidance on the timing of preventive maintenance treatments was the main motivation for this study. On the basis of different evaluation criteria, several mathematical models to estimate optimum timing (OT) of various maintenance treatments were developed. On the basis of long-term benefits, the Area2T model was found to be a rational and practical tool to estimate OT for various maintenance treatments by adjusting the model's parameters. The sensitivity and practical use of the models are demonstrated in the paper. Although the modeling approach uses the existing understanding, the model can be used to estimate OT of a fix on the basis of the pretreatment pavement performance, jump in pavement condition just after treatment, and expected rate of deterioration after treatment application. The required data for the model can be obtained for various treatments from the existing historical performance data collected for pavement management purposes. The model can be calibrated to local needs by matching actual practice and calculated OT for different fix types.
E-Logistics Systems Applications for Service Users and Providers
Authors: Zunder Thomas H. , Islam Dewan Md Zahurul
Published: December 2011

This paper reports the findings of a second-round Delphi study (interactive forecasting method) that explored the issues surrounding integrated e-logistics systems, applications, and policy for varying stakeholders. A three-stage qualitative research approach began with a literature survey, which was followed by a first-round online Delphi survey in the second stage. The first-round Delphi generated some ideas and statements that were used in the second-round Delphi survey (third and final stage). In this survey, the participants were given three choices: agree, disagree, and no comment. The achievement of majority agreement or disagreement on these statements was a central point. For this research, the majority agreement–disagreement was sought at three levels: simple majority, significant majority, and vast majority. The research verifies the applicability of a definition of e-logistics established in the first-round Delphi. The study also identifies the fields of cost-effective e-logistics applications for logistics companies. The research suggests ways to develop an integrated e-logistics system and associated European Union policies.
Using Traffic Simulation Software to Manage Recreational River Boats on Public Lands
Authors: Lowry Michael B. , Laninga Tamara , Zimmerman Monica , Kingsbury Kevin T.
Published: December 2011

This paper describes a novel use of traffic simulation software to model and manage recreational river use. River tourism usually benefits the local economy, but the influx of visitors can also burden the other functions of a river such as agricultural irrigation and critical habitat for flora and fauna. The management of boats on a river is very similar to the management of cars on a freeway. This paper describes how these similarities were modeled with the software package VISSIM. The paper elaborates on the differences encountered, including a discussion about the underlying differences between a traffic engineer's concept of capacity and that of a recreational manager. The model was used to evaluate three management strategies for dealing with future growth: (a) do nothing, (b) build and improve boat ramps, and (c) issue limited boat launch reservations. The three strategies were evaluated on the basis of density (boats per mile) and boat ramp delay (excess minutes because of queuing). The input for the model included nearly 600 boats and 1,200 visitors. The results suggest that lower density and delay are best achieved by issuing limited reservations. The paper is intended for managers of public lands who may not be familiar with traffic simulation software. The approach could be extended to the management of other recreation facilities, such as bike paths and hiking trails. The paper is also useful for traffic engineers interested in new perspectives on capacity and congestion.
Calibration Strategies to Correct Nonresponse in a National Travel Survey
Authors: Roux Sophie , Armoogum Jimmy
Published: December 2011

Nonresponse results in a reduced sample size, but a more important concern of researchers is the possible impact of nonresponse bias. Bias is introduced when those who do not respond to the survey are systematically different from those who do respond on key variables of interest. The response mechanism is defined as “ignorable” when it can be modeled with the available characteristics (e.g., from the sample base). For example, if the nonresponse mechanism depends on the level of income, the respondent sample must be reweighted according to the distribution of income to correct the nonresponse errors. For the French National Travel Survey 2007–2008, the sample was drawn directly from the census and the list of new residences built since then. Therefore, there is considerable information about respondents and nonrespondents. The response mechanism is modeled first, and then calibration strategies are discussed. The nonresponse biases are quantified by using auxiliary information in different calibration exercises.
Design of a Strategic-Tactical Stated-Choice Survey Methodology Using a Constructed Avatar
Authors: Le Vine Scott , Lee-Gosselin Martin , Sivakumar Aruna , Polak John
Published: December 2011

This paper presents findings from a small-sample qualitative study on people's activity travel behavior in the presence or absence of carsharing. A carsharing service provides its subscribers with short-term access to a fleet of shared cars. In previous research, subscribers have reported distinctive travel patterns, such as more car usage by subscribers than by non–car owners but less than by car owners. Reflexive techniques were used in which interviewees adapted a week of their recent activity travel behavior in response to stimuli. Findings from this study informed the design of a stated-choice survey that addressed three principal forms of complexity: (a) strategic-tactical choice situations, (b) situations in which respondents might select multiple interacting options in a single choice situation, and (c) situations in which sufficient knowledge of the individual survey respondent to tailor such a complex choice situation could not feasibly be gathered during a single interview. In the proposed design, the respondent indicates a strategic choice of which methods of travel to make available for use given a set of representative out-of-home activities. Accessibility to each activity by various means of travel is generated by using empirical distributions from Britain's National Travel Survey data sets to maximize plausibility of the information presented to respondents. An avatar (a virtual character for purposes of the survey) is constructed for each respondent on the basis of a small set of self-reported demographic characteristics. The use of multiday activity travel diaries would ideally involve multiple points of contact with each respondent at substantial cost. Therefore, an alternative method involving a single interview per respondent was sought.
Information Categorization Based on Driver Behavior for Urban Lane-Changing Maneuvers
Authors: Sun Daniel (Jian) , Elefteriadou Lily
Published: December 2011

During recent years, transportation researchers have developed various algorithms to model lane-changing behavior on highways and urban streets. However, most of these models were derived and validated using data such as vehicle trajectories, with no consideration of driver characteristics. Focus group studies were conducted to obtain driver-related information so that driver characteristics could be incorporated into lane-changing models. Different lane-changing scenarios on urban streets were examined and discussed during the focus group meetings. The likelihood of initiating lane changes under each scenario was determined, and participating drivers were categorized according to their background information and verbal responses. Two types of information were used to establish a relationship between driver characteristics and lane-changing behavior: quantitative and qualitative responses from participants. Recommendations are provided for the implementation of study findings.
Safety Effectiveness of Actuated Advance Warning Systems
Authors: Appiah Justice , Naik Bhaven , Wojtal Remigiusz , Rilett Laurence R.
Published: December 2011

Driver behavior within the dilemma zone can be a major safety concern at high-speed signalized intersections. The Nebraska Department of Roads (DOR) has developed and implemented an actuated advance warning dilemma zone protection system. This paper investigates the impact that system has had on safety at high-speed signalized intersections. The operating algorithm has been designed such that the system continually monitors an upstream detector, as well as traffic at the intersection, to predict the onset of the yellow signal indication. Flashing beacons are used to warn drivers of the impending end of the green indication. Although these systems have received positive reviews from the public—and commercial vehicle operators in particular—there has been no comprehensive analysis of their effect on safety. The focus of this research was to address this evaluative need and provide answers about the effectiveness of the Nebraska DOR system in improving safety. Crash records from before and after the implementation of the system at 26 intersections were compared. In addition, 29 control intersections were used to compare crash rates over time, and a fully Bayesian technique was employed to ensure that no exogenous variables affected the study. Results of the analysis were promising (an overall crash reduction rate of 8%) and suggested that the use of the system should be encouraged as an effective safety treatment for the dilemma zone problem at high-speed signalized intersections.
Evaluation of Lighted Pavement Marker Stop Bars at Intersections with Light Rail Lines
Authors: Tydlacka Jonathan , Voigt Anthony P. , Langford Walter C.
Published: December 2011

This paper presents an evaluation of the use of lighted pavement markers parallel to an intersection stop bar for three treatment intersections in Houston, Texas. The line of pavement markers was active, with a red light displayed from each marker during the red interval of the traffic signal. Each lighted pavement marker contained multiple LEDs, which operated such that each marker displayed an alternating wigwag pattern. The intended impact of the pavement markers was to reduce red light running violations and crashes on the intersection approach to an arterial that had an at-grade light rail line within its median. A before-and-after study was conducted to determine changes in crashes, red light running violations, and right turn on red violations at the study sites (right turns on red are prohibited at all the study sites). The analysis results showed that the lighted pavement markers reduced red light running violations at all three treatment sites, with two of the three reductions being statistically significant. Right turn on red violations were also reduced, and the reduction was statistically significant at all three treatment sites. A fourth site was chosen as a comparison (nontreatment) site, and the before-and-after study showed no notable change in the number of red light running violations or right turn on red violations at this site.