bluuebunny/crossref_metadata_2025 huggingface dataset:
Elevated polycyclic aromatic hydrocarbons in a river floodplain soil due to coal mining activities
Authors: Hofmann T. , Pies C. , Yang Y.
Published: November 2007

Elevated PAH concentrations were found in soil samples collected along the Mosel River. These contaminations were associated with the occurrence of coal particles found in the soil. The majority of the PAH contamination in the soils was linked to coal mining activities in the Saar region. Density and grain size separation showed a similar PAH distribution pattern in all of the fractions, indicating a uniform origin of PAHs. Together with coal petrography a good correlation between TOC and PAHs concentration confirmed the impact of former coal mining activity on the PAHs distribution in study area.
Chemistry and treatment of ground water in the Vojvodina
Authors: Stauder S.
Published: November 2007

Due to the geological and hydrochemical characteristics, the majority of the ground waters in the Vojvodina possess an unusual chemistry. Mainly this concerns their high alkalinity, low hardness and high contents in natural organic matter. Moreover the concentrations of arsenic, boron, ammonia and methane are elevated in many waters. Arsenic is present in the inorganic species arsenate(III) and arsenate(V), which are toxic to humans. Complex and expensive technology is required for these types of waters to produce drinking water for the public supply. Amongst others, the treatment process would have to include flocculation with high dosages of chemicals and for some waters also reverse osmosis, resulting in waste water amounts of up to 30%. The latter is critical since the exploited aquifer recharges very slowly. The Tisza River is an alternative resource, especially in the case that bank filtrate extraction could be implemented.
Groundwater protection and diffuse nitrogen emissions to surface waters – which catchment areas have to be considered?
Authors: Schilling C. , Zessner M. , Blaschke A.P. , Gutknecht D. , Kroiss H.
Published: November 2007

Two Austrian case study regions within the Danube basin have been selected for detailed investigations of groundwater and surface water quality at the catchment scale. Water balance calculations have been performed using the conceptual continuous time SWAT 2000 model to characterise catchment hydrology and to identify individual runoff components contributing to river discharge. Nitrogen emission calculations have been performed using the empirical emission model MONERIS to relate individual runoff components to specific nitrogen emissions and for the quantification of total nitrogen emissions to surface waters. Calculated total nitrogen emissions to surface waters using the MONERIS model were significantly influenced by hydrological conditions. For both catchments the groundwater could be identified as major emission pathway of nitrogen emissions to the surface waters. Since most of the nitrogen is emitted by groundwater to the surface water, denitrification in groundwater is of considerable importance reducing nitrogen levels in groundwater along the flow path towards the surface water. An approach was adopted for the grid-oriented estimation of diffuse nitrogen emissions based on calculated groundwater residence time distributions. Denitrification in groundwater was considered using a half life time approach. It could be shown that more than 90% of the total diffuse nitrogen emissions were contributed by areas with low groundwater residence times and short distances to the surface water. Thus, managing diffuse nitrogen emissions the location of catchment areas has to be considered as well as hydrological and hydrogeological conditions, which significantly influence denitrification in the groundwater and reduce nitrogen levels in groundwater on the flow path towards the surface water.
Diagrams for evaluating groundwater quality
Authors: Fiorucci A.
Published: November 2007

Some special diagrams for evaluating the chemical properties of groundwater intended for human consumption are introduced, in accordance with the Italian legislation assimilating EEC Directive 91/271 concerning the treatment of urban waste water and EEC Directive 91/676 related to the protection of waters against contamination by nitrates from agricultural sources. Although the limits imposed by the legislation reflect the Italian situation, they do however conform to directives concerning the whole European Community and offer a response to international guidelines promulgated by, for example, the World Health Organization so they are also suitable for use in national contexts other than Italy. Moreover, a diagram is introduced for monitoring the quality of water destined for agriculture, in particular for irrigation and the special issue of soil protection. In this case, in the absence of specific national and/or European laws and/or Directives, reference was made to the standards of the California Water Quality Control Board. The parameters and the relative limits have been taken from such standards, to identify three quality classes of water for agricultural use with evaluation of use. Plotting such diagrams is very simple: they can be used for improving presentation and interpretation of chemical data and, most of all, to provide comparisons between different water resources or to evaluate possible changes over time. Some examples, reported in the text, will aid understanding their use and interpretation.
Risks for groundwater contamination from domestic waste water: tracers, model applications and quality criteria
Authors: Zessner M. , Blaschke A.P. , Farnleitner A.H. , Fenz R. , Kavka G.G. , Kroiss H.
Published: November 2007

Infiltration of municipal or domestic waste water happens as unwanted or even planned form of waste water disposal as: infiltration of septic tank effluents, leakage from pits in rural areas, exfiltration from sewer systems and infiltration of biologically treated waste water in regions with lack of receiving surface waters. Suitable markers for domestic waste water in groundwater are boron (low dilution) and carbamazepine (high dilution). Pathogens and oxygen depletion represent the main risk for drinking water quality arising from domestic waste water in groundwater. Even infiltration of biologically very well treated waste water will cause zones in groundwater where drinking water standards cannot be met. The extent of these zones may vary between <20 m and several kilometres from the point of infiltration depending on the local situation.
A novel approach in numerical simulation of contaminant removal by air sparging
Authors: Jacimovic N. , Hosoda T. , Ivetic M. , Kishida K.
Published: November 2007

The paper presents a mechanistic/deterministic model for simulation of mass removal during air sparging. From the point of numerical modeling, there are two issues considering air sparging: modeling of air flow and distribution and modeling of mass transport and transfer. Several processes, which are commonly neglected, such as air channeling and pollutant advection by the water phase, are taken into account. The numerical model presented in this paper considers all relevant for mass transfer during the air sparging. Model includes hydrodynamics of air and water phase; calculated air volume content is divided into a number of air channels surrounded by the water phase, which is divided into two compartments. First compartment is immobile and it is in contact with air phase, while the second compartment is mobile. This “mobile-immobile” formulation is a common approach for description of solute transport by groundwater. Mass transfer between two water compartments is modeled as a first order kinetic, where the mass transfer coefficient, representing diffusion and advection in the water phase towards the air channels, is parameter needed to be calibrated. Sorption for both water compartments is considered.

The adopted model of contaminant evaporation at the air-water interface is verified by comparison with experimental results available from published sources. Model is used for simulation of two-dimensional air sparging laboratory experiment. Good overall agreement is observed. It is showed that the efficiency of air sparging can be influenced by natural groundwater flow.
Towards a global multi objective optimization of wastewater treatment plant based on modeling and genetic algorithms
Authors: Béraud B. , Steyer J.P. , Lemoine C. , Latrille E. , Manic G. , Printemps-Vacquier C.
Published: November 2007

The optimization of the Benchmark Simulation Model 1 (BSM1) through a multi objective genetic algorithm (MOGA) is studied in this paper. First, the optimization of the set points of the two Proportional Integral (PI) controllers proposed in BSM1 is performed. Then, a new controller layout composed of three PI controllers is proposed and the set points are also optimized. Among all performance indexes proposed in BSM1, only the effluent quality and the energy consumption for pumping and aeration were taken into account in both optimization problems. Since these two objectives are conflicting, the use of the MOGA allows in both cases a direct visualization of the possible trade-offs through a Pareto curve. These two case studies showed the feasibility of such optimizations even when dealing with computing intensive model like the full scale waste water treatment plant (WWTP) model.
Operationalising uncertainty in data and models for integrated water resources management
Authors: Blind M.W. , Refsgaard J.C.
Published: November 2007

Key sources of uncertainty of importance for water resources management are (1) uncertainty in data; (2) uncertainty related to hydrological models (parameter values, model technique, model structure); and (3) uncertainty related to the context and the framing of the decision-making process. The European funded project ‘Harmonised techniques and representative river basin data for assessment and use of uncertainty information in integrated water management (HarmoniRiB)’ has resulted in a range of tools and methods to assess such uncertainties, focusing on items (1) and (2). The project also engaged in a number of discussions surrounding uncertainty and risk assessment in support of decision-making in water management. Based on the project's results and experiences, and on the subsequent discussions a number of conclusions can be drawn on the future needs for successful adoption of uncertainty analysis in decision support. These conclusions range from additional scientific research on specific uncertainties, dedicated guidelines for operational use to capacity building at all levels. The purpose of this paper is to elaborate on these conclusions and anchoring them in the broad objective of making uncertainty and risk assessment an essential and natural part in future decision-making processes.
Algebraic solution of the mass balanced ADM1 to predict the steady state and to optimise the design of the anaerobic digestion of sewage sludge
Authors: de Gracia M. , Huete E. , García-Heras J.L. , Ayesa E.
Published: November 2007

This paper proposes an algebraic solution of the mass and charge balanced ADM1 model to predict the steady state performance of an anaerobic digester for sewage sludge treatment. The algebraic solution consists of three sequential stages: a kinetic stage that considers only the slowest transformations of the model, a stoichiometric stage based on the complete mass fluxes of the biological process and a physicochemical stage from which some digester outputs are calculated. The predictive capacity and the applicability of this model solution are corroborated by its comparison to the differential equation's model solution and the experimental data of a real case study. The algebraic solution is used to explore the digester response under different operational conditions. An example of application is used to verify the potential of the algebraic solution to be used, together with optimisation algorithms, for optimising the design of the digester and the operational conditions for specified performance criteria, such as effluent quality.
Elemental balance based methodology to establish reaction stoichiometry in environmental modeling
Authors: Takács I. , Vanrolleghem P.A. , Wett B. , Murthy S.
Published: November 2007

Kinetic models in activated sludge, anaerobic digestion and other environmental modeling fields rely on the proper formulation of stoichiometric coefficients. Elemental balancing provides a simple and rigorous way to establish the stoichiometric coefficients of reactions represented in the Gujer matrix. The deduction of these coefficients is frequently trivial, from basic mass balancing considerations. In more complex cases, such as the Anammox growth reaction, rigorous elemental balancing is required to establish the proper formulation. This paper demonstrates the methodology based on a simple aerobic heterotrophic growth reaction where stoichiometry coefficients (such as the (1-YH)/YH term for oxygen) are well known. In the second step the methodology is applied for the Anammox growth reaction. The fraction of N2 gas in current models originates from the NH4+ and the NO2− electron donor/acceptor pair in equal proportion. This paper demonstrates that this stoichiometry is a simplification leading to elemental balance errors. The proper stoichiometric coefficients are derived.
Kinetics of autothermal thermophilic aerobic digestion – application and extension of Activated Sludge Model No 1 at thermophilic temperatures
Authors: Kovács R. , Miháltz P. , Csikor Zs.
Published: November 2007

The application of an ASM1-based mathematical model for the modeling of autothermal thermophilic aerobic digestion is demonstrated. Based on former experimental results the original ASM1 was extended by the activation of facultative thermophiles from the feed sludge and a new component, the thermophilic biomass was introduced. The resulting model was calibrated in the temperature range of 20–60 °C. The temperature dependence of the growth and decay rates in the model is given in terms of the slightly modified Arrhenius and Topiwala-Sinclair equations. The capabilities of the calibrated model in realistic ATAD scenarios are demonstrated with a focus on autothermal properties of ATAD systems at different conditions.
Effect of urban drainage on bioavailability of heavy metals in recipient
Authors: Kominkova D. , Nabelkova J.
Published: November 2007

Heavy metals comprise one of the most hazardous groups of pollutants entering the aquatic environment. Their behaviour and ecotoxicological effects are not well understood especially if they are occur as a mix of metals. Drawing on data from three Prague creeks, the paper illustrates changes in heavy metals bioavailability resulting from different environmental conditions and related differences in urban drainage types. Heavy metals in sediment from creeks impacted by stormwater drain discharges are more bioavailable and accumulate in organisms to higher concentrations than in organisms from creeks affected by combined sewer overflows. The results also show that bioassay levels of lead in fish from the creeks exceed acceptable concentrations for human consumption (EC 466/2001) and therefore represent a potential health risk for humans. The results demonstrate the importance of providing improved interception efficiency in the drainage system structures. In particular, a higher level of interception of fine particles is critical, because of their higher metal adsorption capacity than for coarser particles.
Bioassessment of wet-weather pollution impacts on fine sediments in urban waters by benthic indices and the sediment quality triad
Authors: Lafont M. , Grapentine L. , Rochfort Q. , Marsalek J. , Tixier G. , Breil P.
Published: November 2007

Benthic invertebrate assessments can be used to gauge the impact of urban wet-weather flows in receiving waters. Experiences from Cemagref in France have shown that standardized benthic indices (e.g. Oligochaete Index of Sediment Bioindication - IOBS) can be used to reliably determine the ecological status of urban streams and can be incorporated into the new European Water Framework Directive. The Canadian studies on streams and stormwater ponds using chemical analyses, benthic toxicity testing and benthic invertebrate community structure (i.e. the sediment quality triad) comparisons have shown that toxicity was more likely to occur in ponds at sites with higher concentrations of heavy metals and heavier polycyclic aromatic hydrocarbons, and at greater water depths, where fine sediments from urban runoff accumulated. A more comprehensive evaluation of wet-weather flow impacts could be obtained by combining approaches from both countries.
Clinical characteristics and mode of inheritance of familial focal seizures in Standard Poodles
Authors: Licht Barbara G. , Lin Shili , Luo Yuqun , Hyson Linda L. , Licht Mark H. , Harper Kathleen M. , Sullivan Stacey A. , Fernandez Soledad A. , Johnston Eric V.
Published: November 2007

Objective—To determine clinical characteristics and mode of inheritance of seizures in a family of Standard Poodles.

Design—Case series.

Animals—90 Standard Poodles descended from the same maternal bloodline (30 with probable idiopathic epilepsy [PIE] and 60 without any history of seizures).

Procedures—Researchers contacted owners to determine whether dogs had ever had any seizures and, if so, the nature of any such seizures and any potential underlying causes. Dogs were considered to have PIE if they were between 6 months and 7.5 years old at the time of seizure onset and had no evidence of any underlying cause. To determine the mode of inheritance, segregation analyses were designed to allow the family to be analyzed as a whole, as opposed to as nuclear families. Competing models of inheritance were compared statistically for their ability to explain the data.

Results—Of the dogs with PIE, 28 (93%) had focal onset seizures with or without secondary generalization. Median age of onset was 3.7 years; 6 dogs were > 5 years old at the onset of seizures. Segregation analyses strongly suggested that PIE was inherited as a simple recessive autosomal trait with complete or almost complete penetrance.

Conclusions and Clinical Relevance—Results suggested that in this family of Standard Poodles, PIE was inherited as a simple recessive autosomal trait with complete or almost complete penetrance. Seizures often had focal, as opposed to generalized, onsets, and it was not uncommon for seizures to begin after 5 years of age.
A follow-up study of neurologic and radiographic findings in working German Shepherd Dogs with and without degenerative lumbosacral stenosis
Authors: Steffen Frank , Hunold Katharina , Scharf Gernot , Roos Malgorzata , Flückiger Mark
Published: November 2007

Objective—To identify radiographic abnormalities associated with degenerative lumbosacral stenosis (DLSS) in German Shepherd Dogs (GSDs) and determine whether specific radiographic abnormalities could be used to identify dogs at risk of developing DLSS.

Design}Cohort study.

Animals—33 GSDs working as police dogs.

Procedures—Results of physical, neurologic, and orthopedic examinations were used to identify dogs with DLSS. Survey radiography of the lumbosacral junction was performed, and radiographs were compared with radiographs obtained 3 years earlier.

Results—DLSS was diagnosed in 15 of the 33 (45%) dogs. Thirteen of the 15 dogs with DLSS and 14 of the 18 dogs without DLSS had radiographic abnormalities of the lumbosacral junction. Twenty-two (67%) dogs were able to perform unrestricted duties, including 3 dogs with suspected DLSS. Six (18%) dogs had been excluded from active duty during the period of surveillance because of DLSS. Significant progression in specific clinical and radiographic signs was detected, but multiple logistic regression analysis did not identify any radiographic signs that could be used to predict the development of DLSS.

Conclusions and Clinical Relevance—Results suggested that survey radiography cannot be used to predict development of DLSS in working GSDs.
Evaluation of total and ionized calcium status in dogs with blastomycosis: 38 cases (1997–2006)
Authors: Crews Laura J. , Sharkey Leslie C. , Feeney Daniel A. , Jessen Carl R. , Ruska Tammy
Published: November 2007

Objective—To determine blood ionized calcium (iCa) and serum total calcium (tCa) concentrations in dogs with blastomycosis and to evaluate whether serum tCa concentration, albumin-adjusted serum calcium concentration (AdjCa-Alb), and total protein–adjusted serum calcium concentration (AdjCa-TP) accurately predict iCa status.

Design—Retrospective case series.

Animals—38 client-owned dogs with a cytologic diagnosis of blastomycosis.

Procedures—Dogs were classified as hypocalcemic, normocalcemic, or hypercalcemic on the basis of blood iCa concentration, serum tCa concentration, AdjCa-Alb, and AdjCa-TP; classification on the basis of serum tCa concentration, AdjCa-Alb, and AdjCa-TP was compared with blood iCa concentration.

Results—Except for 2 hypercalcemic dogs, all dogs had blood iCa concentrations within the reference interval. Use of serum tCa concentration overestimated hypocalcemia in 57.9% (22/38) of dogs and underestimated hypercalcemia in 1 dog. Use of AdjCa-Alb correctly reclassified all dogs as normocalcemic that were classified as hypocalcemic on the basis of serum tCa concentration, but failed to predict hypercalcemia in 1 dog. Use of AdjCa-TP correctly reclassified all but 2 dogs as normocalcemic that were classified as hypocalcemic on the basis of serum tCa concentration, and failed to predict hypercalcemia in 1 dog. No correlation was found between blood iCa concentration and serum concentrations of tCa, total protein, and albumin; AdjCa-Alb; or AdjCa-TP.

Conclusions and Clinical Relevance—High blood iCa concentration was uncommon in dogs with blastomycosis. Hypoalbuminemia contributed to a low serum tCa concentration despite a blood iCa concentration within reference limits. The use of serum tCa concentration, AdjCa-Alb, and AdjCa-TP may fail to identify a small number of dogs with high blood iCa concentrations.
An outbreak of cryptosporidiosis among alpaca crias and their human caregivers
Authors: Starkey Simon R. , Johnson Amy L. , Ziegler Peter E. , Mohammed Hussni O.
Published: November 2007

Case Description—6 alpaca crias from a single farm were examined because of diarrhea (n = 4) or decreased fecal production (n = 2).

Clinical Findings—Cryptosporidium parvum was identified by means of fecal flotation in samples from 5 of the 6 crias, and a diagnosis of cryptosporidiosis was made. In the remaining cria, a presumptive diagnosis of cryptosporidiosis was made. Three people involved in caring for the crias from this farm were subsequently confirmed to have cryptosporidiosis, and 3 other people were suspected to have cryptosporidiosis. Sequence analysis of the ssu rDNA gene loci confirmed C parvum as the causative agent in 4 of the 6 crias. Subsequent evaluation of the farm revealed 2 additional crias confirmed to have cryptosporidiosis. Stocking densities on the farm were high, with approximately 20 adults/acre in some pastures.

Treatment and Outcome—All 6 hospitalized crias were given supportive treatment consisting of antimicrobials, gastroprotectants, and fluids. All but 1 survived. Farm owners were advised to decrease stocking density on the farm.

Clinical Relevance—Findings suggested that zoonotic transmission of C parvum from alpacas to humans can occur.
Polarization and coherence for vectorial electromagnetic waves and the ray picture of light propagation
Authors: Luis Alfredo
Published: November 2007

We develop a complete geometrical picture of paraxial light propagation including coherence phenomena. This approach applies both for scalar and vectorial waves via the introduction of a suitable Wigner function and can be formulated in terms of an inverted Huygens principle. Coherence is included by allowing the geometrical rays to transport generalized Stokes parameters. The degree of coherence for scalar and vectorial light can be expressed as simple functions of the corresponding Wigner function.
Some Explicit Krein Representations of Certain Subordinators, Including the Gamma Process
Authors: Donati-Martin Catherine , Yor Marc
Published: November 2007

We give a representation of the Gamma subordinator as a Krein functional of Brownian motion, using the known representations for stable subordinators and Esscher transforms. In particular, we have obtained Krein representations of the subordinators which govern the two parameter Poisson–Dirichlet family of distributions [23].
Infrared Catastrophe for Nelson’s Model—Non-Existence of Ground State and Soft-Boson Divergence
Authors: Hirokawa Masao
Published: November 2007

We mathematically study the infrared catastrophe for the Hamiltonian of Nelson’s model when it has the external potential in a general class. For the model, we prove the pull-through formula on ground states in operator theory ﬁrst. Based on this formula, we show both non-existence of any ground state and divergence of the total number of soft bosons.
ConnectOregon Program for Funding Multimodal Transportation Projects
Authors: Rodwell Julie F. , Jackley John L. , Kale Steven R.
Published: November 2007

In 2005, the Oregon legislature passed a transportation funding law providing $100 million of state lottery bonding revenues to invest in aviation, marine, rail, and transit infrastructure through a multimodal transportation fund. Known as ConnectOregon, the program focuses on improving connections among roads and other modes to integrate components of the transportation system better, improve the flow of commerce, and reduce delays. Of the $100 million, a minimum of $15 million will be distributed to each of five regions established in the legislation, with the remaining $25 million allocated competitively across regions. A total of 103 applications were submitted for funding. Before the applications were reviewed by regional and modal review groups, staff from the Oregon Department of Transportation reviewed the applications for completeness, and a consultant team reviewed the applications for technical feasibility. A consensus committee reviewed the regional and modal review group recommendations and developed a consensus recommendation to the Oregon Transportation Commission (OTC). On July 19, 2006, OTC approved 43 projects totaling just under $100 million to enter negotiations for funding.
Decision Support System for Combined Transportation and Utility Construction Strategy
Authors: Chou Chien-Cheng , Caldas Carlos H. , O'Connor James T.
Published: November 2007

Highway projects often require that adjacent utilities be adjusted to make room for new or expanded highway facilities. As an increasing number of highway projects are constructed in congested, interference-prone environments, timely completion of utility adjustment work is more critical than ever. The conventional strategy used by state departments of transportation demands that each utility owner involved complete its respective adjustments before highway construction. This strategy may present numerous challenges and can carry with it serious consequences for state departments of transportation, utility owners, and the traveling public. One major new strategic approach sporadically used by state departments of transportation within the past decade is to combine utility adjustment work with the highway contractor's scope of work and theoretically to reduce some associated complications and risks. This strategy is called combined transportation and utility construction (CTUC), and it offers many benefits while presenting its own set of disadvantages and challenges. Hence, it is necessary to design a decision support system (DSS) for use during the highway planning and design phases. Such a DSS could help both state transportation and utility decision makers determine when to use the CTUC strategy. Results of the CTUC DSS's verification and validation show that the CTUC DSS can facilitate communication and coordination throughout the entire CTUC decision-making process.
Benchmarking of Large Design–Build Highway Projects
Authors: Shrestha Pramen Prasad , Migliaccio Giovanni Ciro , O'Connor James T. , Gibson G. Edward
Published: November 2007

For generations, highway projects in the United States have been delivered with the traditional design–bid–build (DBB) project delivery method. In 1990, FHWA introduced Special Experimental Project Number 14 (SEP-14) to encourage state agencies to use more efficient alternative methods for delivering projects. As of 2002, approximately 140 SEP-14 projects have been built according to the design–build (DB) delivery method. Although the use of the DB method for transportation projects has increased noticeably in the past decade, attempts to measure project performance under DB as against DBB have been limited to small projects. To fill this research gap, an input-versus-output benchmarking approach was used to assess the performance of large DB highway projects. By means of this approach, factors that could affect performance of highway projects were identified, and a comprehensive methodology for benchmarking was developed. A sample of four DB projects (with contract amounts ranging from $126 million to $1.4 billion) was analyzed to determine how project characteristics and DB practices (inputs) affect project performance in terms of cost and schedule (outputs). Project cost and schedule performance show clear trends against 15 input factors. More data points are needed to determine correlations between these inputs and outputs. In addition, 11 DBB projects (with contract amounts ranging from $50 million to $100 million) were selected for a statistical comparison with DB projects.
Performance in the Project Trailer
Authors: Murdough Ginger , Drecksel Debra , Sharp Gary , Ernzen Jim
Published: November 2007

It is a well-established fact that construction is a complex process that involves technical and personal skills and requires many entities to work together to achieve a successful result. For that reason, formal partnering on construction projects in recent years throughout the United States has become a popular approach to total quality management. Although most owners and contractors agree that partnering is a benefit to project performance, sometimes project participants go through the motions without really committing to the process. The Arizona Department of Transportation has developed a sophisticated partnering evaluation system that can measure the performance of its project teams relative to their ability to work together. The result is an accurate assessment tool that can be used by all members of the project team to determine at any time during the project if a performance problem is brewing and that thereby allows the team leadership to react and take corrective action.
Safety Impacts of Access Management Techniques in Utah
Authors: Schultz Grant G. , Lewis Jeff S. , Boschert Tim
Published: November 2007

Traffic volumes and congestion across Utah have continued to increase in recent years, particularly on arterial streets. This increased traffic volume has amplified the emphasis on implementing access management techniques (i.e., raised medians or driveway consolidation) to alleviate some of the safety concerns associated with access on arterial streets. To determine the safety benefits provided by access management techniques in Utah, an evaluation of the safety performance of arterials in which access management techniques have been implemented within the state was performed. To complete the evaluation, a unique, yet proven, tool available through the Utah Department of Transportation was used. This tool is a geographic information system–enabled, web-delivered data almanac that allows researchers to establish specific filters that can be used to sort crash data, identifying high crash locations and establishing crash trends. Several locations where access management techniques have been implemented in Utah were selected for the safety analysis. Although crash rates were not reduced in every case as a result of the access management techniques, other safety improvements were observed. For example, the access management techniques generally reduced the more serious collision types; this resulted in a decrease in the crash severity. Because the overall severity of crashes decreased, the overall economic cost of crashes was reduced. The cost of installing the access management techniques was more than offset by this reduction in the cost of crashes.
What is at Stake?
Authors: Kastenhofer Ilona O.
Published: November 2007

This study investigated ways to improve the effectiveness of the Virginia Department of Transportation's (VDOT's) participation in the land development process. The implications of land development for transportation cannot be overstated, because all transportation demand is based on land use. Understanding how VDOT participates in this process and any current inefficiencies in the process is critical for improving decision making related to land use, which affects the amount of transportation improvements provided by developers in the commonwealth. Increased contributions by developers can substantially increase mobility in the commonwealth. Transportation improvements related to land use are committed and completed development by development. Their combined value, in the range of billions of dollars per year in the commonwealth, is not immediately obvious. VDOT has the opportunity to affect this multibillion-dollar business to maximize the outcome for Virginia. Although localities have all rezoning and site plan approval authority, and accepting VDOT's recommendations is optional, VDOT can maximize its positive impact when supporting localities in their land development processes. This requires acquiring state-of-the-art knowledge about land use issues, building highly collaborative relationships with localities, applying solid technical analysis, and using effective negotiation skills. This study recommends that VDOT improve its effectiveness in the land development review processes in three areas: (a) implement organizational changes to enhance support for land development activities, (b) improve business practices regarding land development, and (c) improve VDOT's ability to participate more effectively in the land development process to maximize the outcome for the commonwealth.
Factors Affecting Worksite Mode Choice
Authors: Dill Jennifer , Wardell Erin
Published: November 2007

Transportation demand management (TDM) programs at employer worksites have been used with varying success across the United States since the 1970s. The overall purpose of these programs is for employers to encourage their employees to commute in modes other than a single-occupancy vehicle. Although employee commute options mandates have disappeared from many localities, the need to manage the demand for travel has not. Understanding what influences work trip mode choices can help transportation and planning agencies implement more effective TDM programs. Data from large worksites in the Portland, Oregon, region were used to evaluate how employer TDM programs, worksite characteristics, and location influence commute mode choice. Many factors contribute to the success of programs at different worksites. Success was measured in the percentage of commute trips made by transit and by walking and bicycling. Regression models showed that although subsidizing transit cost is effective, the choice of commute is also influenced by land use and transit access. Nonfinancial incentives, which can include flex time and a guaranteed ride home program, can also have a significant positive effect.
Wasatch Choices 2040
Authors: Burbidge Shaunna K. , Knowlton Ted , Matheson Alan
Published: November 2007

Wasatch Choices 2040 was a partnership between Envision Utah and the two major metropolitan planning organizations along Utah's Wasatch Front. The purpose of the partnership was to involve the public through a scenario planning process and to consider the role of land use in developing the region's long-range transportation plan. Through 13 public workshops and 5 open houses held in 2005, members of the public expressed their preferences for transportation and land use in their communities. The input from the public informed the development of regional growth principles that have since been adopted by elected officials and will guide transportation and land use decisions in Wasatch Front communities. In addition, results from the public process were used to create four regional transportation and land use scenarios that ultimately led to the creation of a regional vision. Each scenario was tested by using the CentreSim forecasting model, and a vision scenario was created to depict one version of how the Wasatch Front could develop if guided by regional growth principles. Modeling of the regional vision demonstrates that it performs significantly better than the existing long-range plan for several quality-of-life measures, including traffic congestion. This process proved groundbreaking by reminding both land use and transportation professionals that futures cannot be planned in isolation. Transportation affects land use just as much as land use affects transportation. It is a circular relationship that must be accounted for. This process focuses on bringing all interests to the table concurrently to plan for a better future.
Intelligent Transportation Systems for Operation of Roadway Segments in High-Wind Conditions
Authors: Young Rhonda Kae , Liesman Joel
Published: November 2007

Truck safety in high-wind conditions–in particular, the use of intelligent transportation system technology for operating roadway segments during high-wind conditions–is examined. The frequent high-wind conditions in Wyoming cause trucks to overturn and often lead to the closure of a road, resulting in delays, economic impact, and a loss of system reliability. This paper addresses how critical weather conditions can be identified; what the various levels of operations can be, depending on these conditions; the means for identifying at-risk vehicles; and the benefits of implementing an advanced system for operating these high-hazard roadway segments.
Extending Adaptive Cruise Control to Adaptive Driving Strategies
Authors: Kesting Arne , Treiber Martin , Schönhof Martin , Helbing Dirk
Published: November 2007

An adaptive cruise control (ACC) strategy is presented in which acceleration characteristics, that is, driving styles, automatically adapt to different traffic situations. The three components of the concept are the ACC itself, implemented in the form of a car-following model; an algorithm for the automatic real-time detection of the traffic situation based on local information; and a driving strategy matrix to adapt the driving characteristics–that is, the parameters of the ACC controller–to the traffic conditions. As an option, intervehicle and roadside-to-car communication can be used to improve the accuracy for determining the local traffic states. The complete concept was simulated microscopically on a road section with an on-ramp bottleneck by using real loop-detector data for an afternoon peak period as input for the upstream boundary. A small percentage of traffic-adaptive ACC vehicles, a relatively modest local change in the maximum free flow, improves traffic stability and performance significantly. Although the traffic congestion in the reference case was completely eliminated when a proportion of 25% of ACC vehicles was simulated, travel times for the drivers were reduced in a relevant way for much lower penetration rates. The presented results are largely independent of details of the model, the boundary conditions, and the type of road inhomogeneity.
Urban Expressway-Arterial Corridor On-Line Control System Based on Advanced Traveler Information System
Authors: Meng Qiang , Khoo Hooi Ling , Cheu Ruey Long
Published: November 2007

A novel on-line dynamic traffic control strategy for an urban expressway-arterial corridor system is proposed. The corridor system comprises an expressway mainline, on and off-ramps, and surface streets (arterial roads). The ramps are not subjected to any ramp metering control. Assuming that the real-time vehicle arrival and departure can be obtained from the loop detectors on the expressway, the proposed traffic control strategy aims to maintain a predetermined level of service on a congested expressway section by disseminating the congestion information to drivers through various advanced traveler information system means. This strategy consists of three components: expressway mainline control (EMC), on-ramp control (OnC), and off-ramp control (OffC) mechanisms. The EMC mechanism is the major component that diverts vehicles from the expressway to the surface streets, and the OnC and OffC procedures protect the ramps and surface streets from excessive flow. This is because diverting the vehicles without taking into consideration the surface street capacity may cause the overall performance of the corridor system to deteriorate. A simulation-based modeling methodology is developed to evaluate the on-line dynamic traffic control strategy. The evaluation is carried out by performing sensitivity analysis tests of the control parameters used in the strategy. A case study based on a corridor system in Singapore has shown that the traffic control strategy is effective.
Quantifying Reductions in Commute Disutility from Traveler Information Services
Authors: Vasudevan Meenakshy , Wunderlich Karl E.
Published: November 2007

An approach is presented for quantifying commute disutility measures. The approach was demonstrated through a case study conducted for the Washington, D.C., metropolitan area by using an analytical technique called the heuristic on-line web-linked arrival time estimation. “Commute disutility” was defined as having pretrip, en route, and posttrip components on the assumption that there is disutility associated with a commuter's expectation of the trip before trip start, the en route trip experience, and the actual outcome of the trip. Three types of regular commuters were modeled: the nonuser who does not use any traveler information and two kinds of traveler information user–the radio listener who listens to commercial broadcast traffic advisories and the advanced traveler information service user who uses a notification-based service that provides route-specific travel time estimates. Analysis showed that compared to nonusers, traveler information users had lower commute disutility. They had fewer late arrivals at their destinations, and in fewer instances their trip expectation before trip start did not match their actual trip experience. They had fewer instances of feeling at intermediate waypoints along a trip that they were running behind schedule. They modified their trip start times or took alternate routes on more than 65% of the trips. This may have resulted in some disutility because of changes to the regular commute behavior, but they are more informed and therefore more confident of the potential trip outcome than is a nonuser.
Investigation into Shadow Removal from Traffic Images
Authors: Avery Ryan P. , Zhang Guohui , Wang Yinhai , Nihan Nancy L.
Published: November 2007

Traffic surveillance cameras are becoming a viable replacement for inductive loop detectors. The effectiveness of these cameras, however, depends on video image processing algorithms that can alleviate common problems such as shadows, vehicle occlusion, reflection, and camera shake. Shadows have proved to be a major source of error in the detection and classification of vehicles. Three algorithms of increasing complexity are proposed to address the shadow problem. The algorithms each address the need to remove cast shadows from vehicles while preserving self-shadows, or those areas of a vehicle that are hidden from illumination. They are also geared toward real-time analysis, which requires that they can be implemented efficiently and cannot have complex training or learning requirements. The dual-pass Otsu method of shadow removal was the simplest in application but had the poorest performance. The proposed region growing technique, though showing considerable promise, failed when the pixel intensity varied widely in the shadow region. The last technique used edge imaging to recognize shadows as areas with few edges or with edges substantially similar to the background. This method clearly outperformed the other methods and was subsequently proved in a separate paper describing a prototype vehicle detection and classification system.
Adaptive Route Choice Model for Intelligent Route Guidance Using a Rule-Based Approach
Authors: Park Kyounga , Bell Michael G. H. , Kaparias Ioannis , Bogenberger Klaus
Published: November 2007

A route choice model was devised for personalized route guidance; it can adaptively change its routing function according to the demands of the user. A strategy for personalized route guidance is to incorporate an adaptation process into the route selection rules. In a study, regularities in route selection were discovered by using a rule-based approach, the C4.5 algorithm, which had advantages over other methods because of its comprehendible model structure. The route choice model is combined with a user interface, enabling the efficient collection of user feedback. To examine the adaptability of the model, experiments in which user preferences are predefined and later changed during the tests were carried out. The results of the experiments indicate the applicability of the model in personalized route guidance.
Clustering-Based Methodology for Determining Optimal Roadway Configuration of Detectors for Travel Time Estimation
Authors: Bartin Bekir , Ozbay Kaan , Iyigun Cem
Published: November 2007

The problem of finding the optimal roadway segment configuration for road-based surveillance technologies to estimate route travel times accurately is addressed. This problem is inherently a space discretization problem regardless of which travel time estimation function is used. Its ad hoc solution is the equidistant segment configuration, such as every half mile or every 1 mi. It is shown that the space discretization problem can be expressed as the common clustering problem. The novelty of the proposed approach is the use of preliminary vehicle trajectory data to obtain statistically significant traffic regime at the study route. Clustering of sample space-time trajectory data is proposed as a viable methodology for solving the optimal roadway segment configuration problem.