bluuebunny/crossref_metadata_2025 huggingface dataset:
Impact of Health Insurance Status and a Diagnosis of Serious Mental Illness on Whether Chronically Homeless Individuals Engage in Primary Care
Authors: Chwastiak Lydia , Tsai Jack , Rosenheck Robert
Published: October 2012

Objectives. We evaluated the impact of a diagnosis of serious mental illness on use of a primary care provider (vs the emergency department [ED]) as a source of care by people who were chronically homeless.

Methods. We used data from 750 chronically homeless adults enrolled in the 11-site Collaborative Initiative to Help End Chronic Homelessness and identified demographic and clinical characteristics independently associated with using a primary care provider rather than an ED.

Results. The factor most strongly associated with using the ED as a regular source of medical care was previous-year lack of health insurance. Despite high rates of serious mental illness, neither a diagnosis of serious mental illness nor increased severity of psychiatric symptoms was associated with such use.

Conclusions. Findings suggest that people who are chronically homeless and have chronic medical illness would be more likely to access care if they had health insurance. Individual states’ deciding not to expand Medicaid coverage will likely have a tremendous impact on the health outcomes and health care costs associated with this and other vulnerable populations.
Secondary Surge Capacity: A Framework for Understanding Long-Term Access to Primary Care for Medically Vulnerable Populations in Disaster Recovery
Authors: Runkle Jennifer Davis , Brock-Martin Amy , Karmaus Wilfried , Svendsen Erik R.
Published: October 2012

Disasters create a secondary surge in casualties because of the sudden increased need for long-term health care. Surging demands for medical care after a disaster place excess strain on an overtaxed health care system operating at maximum or reduced capacity. We have applied a health services use model to identify areas of vulnerability that perpetuate health disparities for at-risk populations seeking care after a disaster. We have proposed a framework to understand the role of the medical system in modifying the health impact of the secondary surge on vulnerable populations. Baseline assessment of existing needs and the anticipation of ballooning chronic health care needs following the acute response for at-risk populations are overlooked vulnerability gaps in national surge capacity plans.
Evaluation of an Education, Restraint Distribution, and Fitting Program to Promote Correct Use of Age-Appropriate Child Restraints for Children Aged 3 to 5 Years: A Cluster Randomized Trial
Authors: Keay Lisa , Hunter Kate , Brown Julie , Simpson Judy M. , Bilston Lynne E. , Elliott Maureen , Stevenson Mark , Ivers Rebecca Q.
Published: October 2012

Objectives. We evaluated an education, distribution, and fitting program for increasing age-appropriate and correct child restraint use.

Methods. We performed a cluster randomized trial involving 28 early childhood education centers in low socioeconomic status areas in Sydney, Australia. The main outcome was optimal restraint use defined as age-appropriate restraints, installed into the vehicle correctly and used correctly.

Results. One service withdrew after randomization, so data are presented for 689 child passengers, aged 3 to 5 years, from 27 centers. More children attending intervention centers were optimally restrained (43% vs 31%; P = .01; allowing for clustering). More 3-year-olds were using forward-facing seats rather than booster seats, more 4- to 5-year-olds were using booster seats instead of seat belts alone, and there were fewer errors in use at intervention centers. Among non–English-speaking families, more children attending intervention centers were optimally restrained (43% vs 17%; P = .002; allowing for clustering).

Conclusions. The program increased use of age-appropriate restraints and correct use of restraints, which translates to improved crash injury protection. Multifaceted education, seat distribution, and fitting enhanced legislation effects, and the effect size was larger in non–English-speaking families.
Influence of Herbicide and Soil Amendments on Soil Nitrogen Dynamics, Microbial Biomass, and Crop Yield in Tropical Dryland Agroecosystems
Authors: Singh Pratibha , Singh R. P. , Ghoshal Nandita
Published: October 2012

Nitrogen (N) dynamics is the key factor for designing management strategies to achieve sustained crop productivity. A 2‐yr field experiment was performed to examine the influence of herbicide (butachlor [2‐chloro 2′6′ diethyl‐n‐butoxy‐methylacetanilide]; HC) alone or in combination with soil amendments on N dynamics involving N mineralization rate (Nmin), inorganic N pool, N uptake (Nup) by plants, soil microbial biomass N, and crop yield in tropical dryland agroecosystems. The Nmin rate showed distinct seasonal patterns which decreased from rice period to summer fallow except herbicide + animal manure (farmyard manure; HC + AM) and herbicide + crop residue (wheat [Triticum aestivum L.] straw; HC + CR) treatments.The annual rate of Nmin, inorganic N pool, and crop yield were higher in HC + AM, herbicide + chemical fertilizer (NPK; HC + CF), herbicide + green manure {dhaincha [Sesbania aculeata (Willd.) Pers.] shoots; HC + GM} while comparable in HC + CR and HC treatments relative to control (CO). Soil moisture content better predicted variation in Nmin rate compared to soil temperature. Plant Nup and crop yield relative to CO was higher in HC + CF, HC + GM, and HC + AM, comparable in HC + CR while lower in the HC treatment. Annual Nmin rate explained a significant part of variations in annual soil microbial biomass N, inorganic N pool, plant Nup, and crop yield. Results indicate that combined application of HC + AM result in relatively sustained availability of inorganic N and higher crop yield throughout the annual cycle.
Efficiency Comparison of Conventional and Digital Soil Mapping for Updating Soil Maps
Authors: Kempen Bas , Brus Dick J. , Stoorvogel Jetse J. , Heuvelink Gerard B.M. , de Vries Folkert
Published: October 2012

This study compared the efficiency of geostatistical digital soil mapping (DSM) with conventional soil mapping (CSM) for updating soil class and property maps of a cultivated peatland in the Netherlands. For digital soil class mapping, the generalized linear geostatistical model was used. Digital mapping of the soil organic matter (SOM) content and peat thickness was done by universal kriging. The conventional soil class map was created by free survey, while the property maps were created with the representative profile description (RPD) and map unit means (MUM) methods. For each method, we computed the effort invested in the mapping in terms of the sampling and cost densities. The accuracies of the created soil maps were estimated from independent probability sample data. The results showed that for DSM, the cost density could be reduced by a factor of three compared with CSM without compromising accuracy. The map purity of both maps was around 55%. For conventional soil property mapping, the MUM maps were more accurate than the RPD maps. For SOM, CSM‐MUM (RMSE 7.5%) performed better than DSM (RMSE 12.1%), although accuracy differences were not significant. For peat thickness, DSM (RMSE 23.3 cm) performed slightly better than CSM‐MUM (RMSE 24.9 cm). Despite the differences in accuracy being small, the digital soil property maps were produced more efficiently. The cost density was a factor of 3.5 smaller. We conclude that for updating conventional soil maps in the Dutch peatlands, geostatistical DSM can be more efficient, although not necessarily more accurate, than CSM.
Non‐Invasive In Situ Measurement Gas Diffusivity of Topsoil
Authors: Weltecke Katharina , Friedrich Martina M. , Gaertig Thorsten
Published: October 2012

A commonly accepted method to measure the in situ gas diffusivity of topsoil is based on the diffusion of a test gas from an open‐bottomed chamber that is inserted a few centimeters into the soil. The aim of this study is to develop an easy‐to‐use approach to determine the gas diffusivity of topsoil at sites where the chamber cannot be inserted into the soil. In the existing method, the diffusion of gas into the soil is a quasi‐one‐dimensional problem with an analytical solution for gas concentration in the chamber as a function of time t. This one‐dimensionality is no longer given in the case of a chamber placed on top of the soil. In the newly suggested method, simulated time series of gas concentrations in a chamber inserted into the soil (Case 1) were compared to those for a chamber placed on top of the soil (Case 2), with equal gas diffusion coefficients for the soil, Ds. We determined a relationship that can be used to convert the chamber concentration for a given Ds at each t in Case 2 to Case 1. The values of Ds can be found iteratively. The method was validated using Ds values different from those used to calculate the function parameters. Practical field measurements of gas diffusivity were also conducted, which show that, on average, both methods yield the same results for an individual site.
A Novel Method to Determine the Volume of Sensitivity for Soil Moisture Sensors
Authors: Sun Yurui , Sheng Wenyi , Cheng Qiang , Chai Jin , Yun Yuliang , Zhao Yandong , Xue Xuzhang , Lammers Peter Schulze , Damerow Lutz , Cai Xiang
Published: October 2012

This study presented a novel method to determine the volume of sensitivity (VOS) for dielectric sensors by frozen soil columns radially thawing from outside inward. The method is based on physical equivalence of the dielectric properties between soil drying–wetting and freezing–thawing transitions. We applied this method to determine/compare (i) the VOSs of two types of fringe field probes (one tube type and one cone type) with sandy silt loam samples at a middle level of soil moisture content (θv = 0.20 cm3 cm−3), (ii) the VOSs of the cone‐type probe with sandy silt loam samples at three levels (θv = 0.10, 0.20, and 0.28 cm3 cm−3), and (iii) the VOSs of the tube‐type probe with three soil textural samples (sand, sandy silt loam, and silty clay). The determined radii of the cone‐type sensor ranged from 3.0 to 4.1 cm and those of the tube‐type sensor from 5.1 to 8.5 cm. These results could be beneficial for improving the technical design of soil dielectric sensors and understanding the effect of soil physical properties on the VOS.
Accounting for Surface Cattle Slurry in Ammonia Volatilization Models: The Case of Volt'Air
Authors: Garcia L. , Génermont S. , Bedos C. , Simon N.N. , Garnier P. , Loubet B. , Cellier P.
Published: October 2012

Process based models have been developed to simulate ammonia (NH3) volatilization after surface slurry spreading, but none of them have managed to realistically represent slurry infiltration into the soil and the development of a specific slurry interface that modifies surface temperature and humidity conditions. To account for these physical effects, it is proposed to add to the model a layer of slurry on the surface of the soil. It is hypothesized that the slurry layer can be regarded as a soil layer from the hydrological point of view, characterized by its specific hydraulic parameters, and whose thickness depends on the quantity and bulk density of the slurry dry matter. An assessment was performed by comparisons with measurements of NH3 volatilization fluxes from two specific datasets. The addition of the slurry layer clearly improved the simulations of both the NH3 volatilization flux and ammoniacal nitrogen (NHX–N) distribution in the soil. This concept together with its parameterization proved to be relevant for accounting for effect of the slurry application rates on volatilization, and subsequent abatement obtained with band spreading. The efficiency factor was improved from –0.35 to 0.71. This concept also succeeded in describing the slurry layer state over the whole range from slurry ponding at the surface to the dried‐out state, via a slurry in an intermediate drying state. This was actually a prerequisite for the good simulation of NH3 volatilization over the whole volatilization event. This approach is promising for extension to various organic materials present at the soil surface.
Trace Elements in Benchmark Soils of Oklahoma
Authors: Richards Jaben R. , Schroder Jackie L. , Zhang Hailin , Basta Nicholas T. , Wang Yanling , Payton Mark E.
Published: October 2012

Natural background concentrations of trace elements in soils must be determined to establish baseline levels for soil remediation and to avoid the establishment of inaccurate or unrealistic guideline levels. The objectives of this study were to establish the background total trace element concentrations including As, Cd, Cr, Cu, Mn, Mo, Ni, Se, Pb, and Zn in 28 Oklahoma benchmark soils and to determine the relationship between soil properties and natural trace element concentrations. Soil samples were analyzed for total trace elements, pH, organic C, clay content, and oxalate‐extractable Al (Alox) and Fe (Feox). Both multiple regression and path analysis were used to examine the relationship between total trace elements and soil properties. The background concentrations of trace elements were (mg kg−1): As (0.75–33.6), Cd (0.13–0.80), Cr (4.30–69.7), Cu (1.94–32.7), Mn (27.4–2165), Mo (0.18–1.80), Ni (2.41–57.3), Pb (2.60–31.7), Se (below detection limit, i.e., <1.25), and Zn (15.3–142). Path analysis confirmed the relationships of the multiple regression but in some cases allowed us to more specifically identify the soil property most associated with the total trace element. In our study, total soil Cd, Cr, Cu, Ni, Pb, and Zn concentrations were dependent largely on clay content. Organic C content also significantly affected total soil Pb concentrations. Total soil As, Mn, and Mo concentrations were most dependent on Alox levels. Path analysis separated direct effects from indirect effects and proved to be an asset when determining which soil properties controlled total soil trace element concentrations.
Soil Accumulation of Nitrogen and Phosphorus Following Annual Fertilization of Loblolly Pine and Sweetgum on Sandy Sites
Authors: Kiser L. C. , Fox T. R.
Published: October 2012

A key question that arises following fertilization of forest plantations in the southeastern United States is whether fertilization has a long‐term effect on nutrient availability and long‐term site quality. Site quality could improve if mineral soil N and P pools are increased but is less likely if only forest floor pools are increased. Rapid forest floor decomposition and nutrient release following harvest likely lead to only rotation‐length increases in nutrient availability. To examine the impact of repeated applications of N and P, forest floor and mineral soil N and P pools were measured at a 24‐yr‐old loblolly pine (Pinus taedaL.) plantation in North Carolina (Southeast Tree Research and Education Site [SETRES]) and 13‐yr‐old loblolly pine and sweetgum (Liquidambar styracifluaL.) plantations in Georgia (Mt. Pleasant) receiving annual incremental fertilizer applications totaling >1000 kg N ha−1and >160 kg P ha−1. Mineral soil N pools varied only slightly. In contrast, fertilization increased forest floor N pools by 300 kg N ha−1at SETRES. Long‐term impacts on site N availability and site quality following these large N applications are unlikely. The forest floor P pool at SETRES was increased by 19.8 kg P ha−1. Fertilization also increased the mineral soil extractable P pool at SETRES to a depth of 1.5 m by 56 kg P ha−1but not at Mt. Pleasant where P fertilization during the previous rotation may have already increased this pool. Observed increases in mineral soil P from fertilization indicated a potential for increased long‐term site quality in terms of higher P availability for future rotations.
Predicting Soil Phosphorus‐Related Properties Using Near‐Infrared Reflectance Spectroscopy
Authors: Abdi Dalel , Tremblay Gaëtan F. , Ziadi Noura , Bélanger Gilles , Parent Léon-Étienne
Published: October 2012

Near‐infrared reflectance spectroscopy (NIRS) is a rapid, inexpensive, and accurate analysis technique for a wide variety of materials, and it is increasingly used in soil science. The objectives of our study were to examine the potential of NIRS to predict (i) soil P extracted by two methods [Mehlich 3 (M3P) and water (Cp)], soil total P (TP), annual crop P‐uptake, and annual P‐budget, and (ii) other soil chemical properties [total C (TC), total N (TN), pH, and K, Al, Fe, Ca, Mg, Mn, Cu, and Zn extracted by Mehlich 3]. Soil samples (n = 448) were taken over a 7‐yr period from an experimental site in Lévis (Québec, Canada) where timothy (Phleum pratense L.) was grown under four combinations of P and N fertilizer. The NIRS equations were developed using 80% of the samples for calibration and 20% for validation. The predictive ability of NIRS was evaluated using the coefficient of determination of validation (Rv2) and the ratio of standard error of prediction to standard deviation (RPD). Results show that M3P, Cp, crop annual P‐uptake, and annual P‐budget were not accurately predicted by NIRS (Rv2 < 0.70 and RPD < 1.75). Similar results were found for K and Cu. However, NIRS predictions were moderately useful for TP, TN, Fe, and Zn (0.70 ≤ Rv2 < 0.80 and 1.75 ≤ RPD < 2.25), moderately successful for TC and Al (0.80 ≤ Rv2 < 0.90 and 2.25 ≤ RPD < 3.00), successful for pH and Mg (0.90 ≤ Rv2 ≤ 0.95 and 3.00 ≤ RPD ≤ 4.00), and excellent for Ca and Mn (Rv2 > 0.95 and RPD > 4.00). The NIRS predictive ability of several soil properties appears to be related to their relationship with soil organic C. Although NIRS can predict several soil properties, prediction of total P was the only soil P‐related property, correlated to soil C, that was moderately useful.
Towards a new drinking water resource classification approach at a river basin scale
Authors: Piel S. , Baurès E. , Masclet S. , Perot J. , Thomas O.
Published: October 2012

This study proposes a new approach for improving resource quality management, monitoring and treatment plant management, whatever the environmental and climatic stressors. First trend analysis of water quality at a river basin scale, based on historical water quality data and multivariate exploitation (principal component analysis, PCA), led to a classification of the monitoring stations with regard to the main pressures (land use, urbanization and hydroclimatic impacts). This method was applied to the Vilaine's watershed, the largest river basin in Brittany, western France, and one which is under agricultural and urban pressure. A complementary research using a UV index was proposed for the evaluation of spatial and temporal variations of water quality. This approach may be considered as a useful and relevant tool to quickly assess the variation of water quality and the main explanatory factors. It also points out monitoring stations under specific stressors considered as outliers regarding UV parameters. Finally, PCA and UV index give complementary results. PCA allows factors influencing drinking water resource to be highlighted and the UV index allows global water quality under specific times and impacts to be reflected.
Genotoxicity and effects of nanosilver contamination in drinking water disinfection
Authors: Dobrović Slaven , Juretić Hrvoje , Ljubas Davor , Vrček Ivana Vinković , Zebić Avdičević Maja , Milić Mirta , Kopjar Nevenka , Nemet Ina
Published: October 2012

This study was conducted to examine the genotoxicity and the influence of silver nanoparticles (AgNPs) contamination when drinking water is exposed to five different disinfection treatments: chlorine, chlorine dioxide, ozone, ozone/chlorine and ozone/chlorine dioxide. Experiments were conducted with water samples of different chemical composition, from three water supply systems in Croatia. AgNPs are of interest because of their use as an antimicrobial in numerous commercial products, and as a drinking water disinfection agent. To examine possible effects of AgNP contamination, the disinfection treatments were repeated with AgNPs in the water samples. AgNP contamination generally caused a decrease in the level of trihalomethanes by up to 59%. Influence of AgNPs on bromide ion incorporation into disinfection by-products (DBPs) was also examined. The most obvious example was the Osi water where ozonation step prior to chlorination increased the bromine incorporation factor from 0.156 to 0.339, while addition of AgNPs limited the increase to 0.249. Also, AgNP presence in almost all disinfection treatments increased dicarbonyl disinfection by-products. All treated waters were tested for genotoxicity using the comet assay and showed similar genotoxic potential. The results are preliminary, but could provide a basis for further studies evaluating the environmental impact of AgNPs in natural aquatic systems.
Riverbank filtration in India – using ecosystem services to safeguard human health
Authors: Sandhu C. , Grischek T.
Published: October 2012

India has great potential to use riverbank filtration (RBF) for drinking water production as an ecosystem service for human health, principally through effective removal of common waterborne pathogens, even during monsoon. Water quality results from site investigations in North India have shown a removal of total and faecal coliform (indicator) bacteria in the range of 1.3 to >5.2 log for total coliforms and 2.3 to >4.2 log for faecal coliforms at the bank filtration schemes of Haridwar, Nainital, Patna, and Mathura. At rural RBF sites, where bank filtrate is collected and supplied by Koops (‘well’ in Hindi), a removal of 1.0–3.4 log and 0.3–2.8 log was observed for total and faecal coliforms respectively. At the RBF sites in Haridwar and Patna, there was only minimal breakthrough of coliforms during monsoon floods, for which disinfection using conventional chlorination was sufficient.
Synergistic electric field enhancement of the effectiveness of chlorine species formed during electrochemical disinfection of drinking water
Authors: Nath Hilary , Langdon Alan
Published: October 2012

In line in situ electrochemical disinfection of drinking water with chloride concentrations as low as 10 mg/L has been demonstrated at practical flow rates of at least 3 m3/day using a novel perforated electrode flow through (PEFT) cell with a 50 μm inter-electrode gap. Sufficient chlorine to achieve 6 log inactivation of Escherichia coli bacteria was produced at applied voltages as low as 5 V and with energy consumptions as low as 0.5 kWh/m3. At slightly higher applied voltages, the specific lethality of electrochemically produced chlorine was enhanced by at least two orders of magnitude to greater than 50 L/mg min. This dramatically enhanced lethality is consistent with a synergistic effect resulting from reversible electroporation when electric fields greater than 1.3 kV/cm are produced. There was no evidence for involvement of other species such as reactive oxygen species (ROSs). Disinfection of drinking water using the PEFT cell is cost competitive with other disinfection technologies and when enhanced by the electric field is much less likely to produce disinfection by products.
(Dis)functional potential of the traditional Montenegrin gender relations model in contemporary identity politics
Authors: Banovic Branko
Published: October 2012

Multiculturalism demands essentialisation of ?cultural differences?, thus
?traditional? gender relations can be recognized as ?differentia specifica?
of a particular community. Special quality of traditional Montenegrin gender
relations is that today we can only know characteristics of a traditional
model of gender relations (not characteristics of real gender relations in
the past). The practical implication in the contemporary politics of identity
can be unrecognizing (or recognizing with silence) culturally generated
disparities within gender relations recognized as the ?specific? ones. The
justification ?it is their culture/tradition? will necessarily imply the
justification for pleasant life of some people, agony of some other or even
justification for the jeopardised physical integrity of some people. If
anthropologists want to intervene in the social reality, they must manoeuvre
within strictly determinated coordinates: about ?traditional? Montenegrin
gender relations we can only know based on ?written? notions; in the politics
of identity only those ?written? notions can be recognized; traditional
notions determine contemporary social relations; they perpetuate culturally
generated disparities; in the multucultural politics of identity answer of
society could be simple - ?it is their culture/tradition?. For such a
manoeuvring, within this kind of limited space of social reality, it is
necessary in same way to harmonize post-cultural theoretical heritage of
contemporary anthropology with essentialisation of cultural differences
(contemporary anthropology have originated against this kind of
essentialisation) - which is one of the most important challenges to
contemporary anthropology.
The second Alexandrian text-type on content analysis
Authors: Ilic Vladimir
Published: October 2012

The paper is divided into three sections. The first one deals with the
problems of the reliability and validity. Second part of the text is devoted
to the discussion among qualitative vs. quantitative approaches supporters.
The issues of the using of computers and some possibilities of comparative
framework in relation to the content analysis are considered into the third
part of the paper.
Positive and negative aspects of social capital: The case of postcommunist societies
Authors: Pavicevic Olivera
Published: October 2012

The paper analyzes social capital's properties in relation with the level at
which it is generated, as a type of social capital. The second part of the
paper is dedicated to examining of possibilities for implementation of the
concept of social capital in various social and political circumstances.
Analysis of the Putnam's concept of social capital in reviewing of the
process of democratization of post-communist societies has shown that
assessment of the social capital?s role in democratic transition of these
societies must take into account specific social and political circumstances
which influenced social capital's trends and forms. In contrast to
economically developed societies with long democratic traditions, it turned
out that social capital in former communist societies developed and moved in
almost opposite directions. It is characterized by competitiveness,
non-community spirit and exclusivity. This may be explained by predominant
informal associating forms as a survival strategy in conditions of
deprivation and ideological mobilization at the time of communist party
states which during transition turned into suspicious conversions of various
capital types. It is an open issue how much the social capital concept is
applicable in post-communist societies of Eastern and Central Europe and how
it should be designed for the purpose of adequate implementation in creating
of social policies.
Citizens' participation in local environmental protection system
Authors: Cikic Jovana
Published: October 2012

Changes in theoretical approach but also practice of planning environmental
protection brought forth the issue of citizens? participation. Active
citizens? participation is particularly stressed at the local environmental
protection system because local community is considered as a framework of
citizens? everyday life. At the same, capacity for citizens? participation is
determined by interactions of three factors: a) general social conditions, b)
characteristics of environmental protection system and c) characteristics of
citizens? environmental awareness. The analysis, based on the results of the
empirical research, is focused on role of citizens as social actors in
environmental protection system at the local community level (city of Novi
Sad). The research starts from the premise that although there is an
elementary citizens? environmental awareness, its manifest dimension is not
well developed primarily due to the to lack of tradition in political
participation, but also inadequate cooperation with relevant institutions
within the system, as well as hierarchy of everyday life problems that
citizens have to deal with that, for the most of them, do not leave enough
space and motives for the engagement of this kind. The purpose of this paper
is to depict factors that stimulate or inhibit needs and capacities for
citizens? participation within the processes of defining, decision making and
implementation of decisions important for environmental protection.
Safety Evaluation of Automated Section Speed Enforcement System
Authors: Montella Alfonso , Persaud Bhagwant , D'Apuzzo Mauro , Imbriani Lella Liana
Published: October 2012

Because speeding is one of the most significant contributing factors to fatal crashes, most road agencies attempt to achieve the right operating speed by imposing speed limits. Speed limit violations are prevalent, even on motorways with speed cameras. A problem with speed camera enforcement is that some motorists brake before passing a camera location and then exceed the speed limit after passing. This sudden braking can cause dangerous situations, crashes, and traffic jams. Furthermore, safe operating speed is not achieved where there are no cameras, especially where enforcement is overt, as in Italy. A new technique to overcome these problems is an automated section speed enforcement system, Safety Tutor. Unlike conventional speed meters, which measure vehicle speed at one point, the new technique determines average speed over a long distance. This study evaluated the safety effectiveness of the Safety Tutor system installed on Italian Motorway A1 Milan–Naples in 2007. An empirical Bayes observational before-and-after study was performed. The estimate of the total crash reduction is 31.2%, with a lower 95% confidence limit of 24.3%. The greatest crash reductions were observed for severe crashes and crashes at curves. Reduction was 55.6% for severe crashes, 26.6% for nonsevere crashes, 43.4% at curves, and 28.4% at tangents. However, the system's effectiveness decreased over time. The crash reduction was 39.4% in the first semester after the system's activation and 18.7% in the fifth semester after activation. Results strongly support activation of the new automated system owing to highly significant and substantial safety effects. The decrease in system effectiveness over time may be correctible with higher levels of enforcement.
Effects of Alcohol on Speeding and Road Positioning of Young Drivers
Authors: Christoforou Zoi , Karlaftis Matthew G. , Yannis George
Published: October 2012

Young people who drink and drive have a relatively higher risk of crash involvement for all breath alcohol concentration (BrAC) ranges. However, not all aspects of the effect of alcohol consumption on the behavior of young drivers have been sufficiently addressed—especially the differentiated effect of alcohol on their driving performance. The behavior of young drivers under the influence of alcohol is explored within this research in a driving simulator experiment in which participants were subjected to a common predefined dose of alcohol consumption. Comparing behavior before and after consumption as well as across individuals and different BrAC levels allows for useful insights into driver behavior, as well as for suggestions on policy interventions. Results indicate strong differences in individuals, mainly because of differentiated driving experience and baseline driving skills. The results also designate reaction time and speeding as the most robust alcohol impairment indicators that affect driver choices directly. Most important, results suggest that the BrAC–speed curve across individuals is not monotonic over all BrAC intervals.
Influence of Cannabis on Fatal Traffic Crashes
Authors: Van Elslande Pierre , Fournier Jean-Yves , Jaffard Magali
Published: October 2012

The influence of cannabis on traffic crashes is a growing concern. Experimental studies provide ample evidence of cannabis influence on psychomotor and cognitive performances. Epidemiological works describe the excess crash risk that this substance causes. Yet this psychotropic drug's influence in causing crashes is still at the center of many discussions. The present analysis exploits crash data in detail to obtain a more precise understanding of the failures that drivers are subject to when they have consumed cannabis, depending on the level of tetrahydrocannabinol (THC) measured in blood samples. Two groups representative of fatal crashes in France were studied: a cannabis group (n = 174) and a control group (n = 174) involving use of neither cannabis nor alcohol. Results of this analysis notably showed that cannabis consumption significantly increased the rate of generalized failures by the driver, reflecting an alteration of all sensorial, motor, and cognitive functions, specifically for high blood levels of THC (>5 ng/mL). At lower levels of intoxication, cannabis leads to a poor diagnosis of driving difficulties.
Child Car Restraints
Authors: Johns Melissa , Lennon Alexia , Haworth Narelle
Published: October 2012

Road trauma is a leading cause of child injury worldwide. In highly motorized countries, injury as a passenger represents a major proportion of all child road deaths and hospitalizations. Australia is no exception, particularly because there are high levels of travel by private motor vehicle to school in most Australian states. Recently, the legislation in Australia governing the type of car restraints required for children younger than 7 years of age has changed and has aligned requirements better with accepted best practice. However, it is unclear what effect these changes have had on children's seating positions or the types of restraints used. A mixed-methods evaluation of the impact of the new legislation on compliance was conducted at three times: baseline (Time 1), after announcement that changes were going to be implemented but before enforcement began (Time 2), and after enforcement commenced (Time 3). Measures of compliance were obtained by two methods: roadside observations of vehicles with child passengers and parental self-report (intercept interviews conducted at Times 2 and 3 only). Results from the observations suggested an overall positive effect. Proportions of children occupying front seats decreased overall, and use of dedicated child seats increased to almost 40% of the observed children by Time 3. However, almost a quarter of the children observed still occupied front seats. These results differed from those of the interview study, in which almost no children were reported as usually traveling in the front seat, and reported use of dedicated restraints with children was almost 90%, more than twice that of the rate in observations.
Moped Rider Violation Behavior and Moped Safety at Intersections in China
Authors: Wang Xuesong , Xu Yilun , Tremont Paul J. , Yang Dongyuan
Published: October 2012

The study identified moped rider violation behavior leading to conflicts and crashes to help guide future countermeasure development. Mopeds (electric bicycles and light motorcycles) are a commonly used personal transportation mode in China, and moped crashes are increasing rapidly. This increase in crashes may be attributable to certain traffic behavior of moped riders. Video recordings were used to acquire data on moped riders' violation behavior and the violation behavior of bicycle, tricycle, and motorcycle riders at signalized intersections. One hundred twenty-five min of video were recorded from 10 intersections, and rider behavior was coded from 1,455 vehicles. Video data showed that moped riders committed more violations than did riders of bicycles, tricycles, and electric bicycles and that moped riders who engaged in violation behavior at intersections were involved in more frequent and more severe conflicts than were moped riders who did not engage in violation behavior. Typical moped violation behavior included running red lights, riding in improper directions, waiting at improper positions, riding in improper lanes, and overloading. Violation behavior was closely associated with the traffic environment (traffic facilities, traffic flow, traffic signal status, and other riders' behavior), but not with either the vehicle's characteristics or the rider's characteristics. This difference suggests that countermeasures related to the traffic environment would be more effective than those related to either vehicle or rider characteristics. Countermeasures within the areas of traffic regulation, traffic management, traffic facilities, vehicle management, and rider education are proposed.
Impact of Environmental Site Location and Groundwater Table Depth on Thickness of Flexible Airfield Pavements
Authors: Zapata Claudia E. , Salim Ramadan A.
Published: October 2012

This comprehensive sensitivity study of a newly developed computer code at Arizona State University incorporates the influence of environmental site factors and the groundwater table depth on flexible airfield pavement design and performance. The newly developed code, called ZAPRAM, is a mechanistically based pavement model based on limiting strain criteria. The completed study used the newly revised U.S. Army Corps of Engineers failure criteria for subgrade shear deformation. The experimental factorial conducted comprised three aircraft types, three levels of as-compacted (optimum) subgrade condition, two levels of design aircraft passes, and an environmental combination of six groundwater table depths and five environmentally different city locations. The methodology used in this study applied the same analytical method to achieve real-time environmental effects on unbound layer modulus as the new AASHTO Mechanistic–Empirical Pavement Design Guide. The results of this effort showed for the first time the quantitative impact of the significant effects of climatic conditions at the design site, coupled with the importance of the depth of the groundwater table, on the predicted design thicknesses. Significant cost savings appear to be quite reasonable by using the principles of unsaturated soil mechanics in the new airfield pavement design procedure in ZAPRAM.
Performance Comparison of Diamond-Enhanced and Tungsten Carbide Teeth for Road Milling
Authors: Dixon Paul A. , Crockett Jeffrey , Jepson Jeffrey
Published: October 2012

When deteriorating asphalt roads are reconstructed or downgraded to gravel roads, the old pavement is ground into reclaimed asphalt pavement by machines conventionally fitted with tungsten carbide teeth for grinding. Tungsten carbide milling teeth must be changed frequently because they sometimes last only 1 or 2 days. Diamond-enhanced milling teeth have been developed as a more durable alternative. The durability of tungsten carbide milling teeth was compared with that of diamond-enhanced milling teeth, and the effect of tooth type on fuel efficiency and machine vibrations was measured. In the tests conducted, on average, the diamond-enhanced milling teeth lasted 40 times longer, improved fuel consumption by 14.3% and 29.9%, and reduced the maximum vibration in a milling machine 79% over tungsten carbide milling teeth.
Performance Evaluation of Uncrushed Aggregates in Unsurfaced Road Applications through Accelerated Pavement Testing
Authors: Mishra Debakanta , Tutumluer Erol , Heckel Gregory
Published: October 2012

The design of low-volume roads and unsurfaced pavements traditionally involves covering prepared subgrade with an aggregate layer of sufficient thickness such that traffic-induced loads are adequately distributed and stresses on the subgrade can be tolerated. Aggregate gradation and field density requirements are commonly the only considerations for constructing acceptable aggregate layers. Aggregate quality aspects and properties often are not considered in detail when aggregate sources with the lowest material hauling and transportation costs are selected. An approach based solely on economic considerations may result in the selection of locally available material for routine use as the primary load-bearing pavement layer. Full-scale test sections were constructed at the University of Illinois at Urbana–Champaign with aggregate materials of different types and qualities over a weak subgrade of controlled strength and tested to failure with the use of an accelerated transportation loading assembly. Pavement performance under near-optimum and flooded aggregate moisture conditions was monitored by measuring the surface profile. In addition, transverse trench sections were excavated to determine the mechanisms contributing to failure. Accelerated testing of a pavement test cell constructed with an uncrushed gravel with high amounts of nonplastic fines showed excessive rut accumulation through internal shear failure of the aggregate layer under near-optimum aggregate moisture conditions. Excavated trench sections clearly indicated the development of a shear surface within the gravel layer that caused a lateral offset in the subgrade deformation with respect to the wheel path. However, under flooded conditions, excessive subgrade movement was found to be the primary mechanism contributing to pavement failure.
Generalized Profitable Tour Problems for Online Activity Routing System
Authors: Chow Joseph Y. J. , Liu Hang
Published: October 2012

A next-generation system for online route guidance and activity recommendations was studied to support decisions that considered multiple activity itineraries whose utilities account for their spatial proximities for a user. For the solution of the underlying problem, the problem of the profitable tour and the problem of the prize-collecting traveling salesman were extended to generalized cases with the expansion of single nodes to clusters to handle various activity types. The generalized formulations addressed several uses, including routing with refueling, the pub crawl problem, and the romantic date problem. Test cases compared an insertion heuristic and a multisolution genetic algorithm with exact solutions. Both algorithms worked well even with the constraints of time windows and with the fast computational times that are necessary for online decision support. The multisolution genetic algorithm tended to be slower than the insertion heuristic was, but the multisolution algorithm could handle a wider variety of problems and could provide a set of solutions from which a user could browse to account for unobserved preferences.
Bilevel Optimization Approach to Design of Network of Bike Lanes
Authors: Mesbah Mahmoud , Thompson Russell , Moridpour Sara
Published: October 2012

A bike lane is an effective way to improve cycling safety and to decrease greenhouse gas emissions with the promotion of cycling. Improvements include high-quality off-road facilities and on-road bike lanes. Whereas construction of off-road lanes is not always possible because of urban land constraints and construction costs, on-road lanes can be a cost-effective alternative. An optimization framework for the design of a network of bike lanes in an urban road network was proposed. This framework identified links on which a bike lane could be introduced. Allocation of a lane to cyclists would increase the use of cycling, although it could disadvantage auto traffic. The presented approach balances the effects of a bike lane for all stakeholders. A bilevel optimization was proposed to encompass the benefits of cyclists and car users at the upper level and a model for traffic and bike demand assignment at the lower level. The objective function was defined by a weighted sum of a measure for private car users (total travel time) versus a measure for bike users (total travel distance on bike lanes). A genetic algorithm was developed to solve the bilevel formulation, which included introduction of a special crossover technique and a mutation technique. The proposed optimization will help transport authorities at the planning stage to quantify the outcomes of various strategies for active transport.
Intermodal Path Algorithm for Time-Dependent Auto Network and Scheduled Transit Service
Authors: Khani Alireza , Lee Sanggu , Hickman Mark , Noh Hyunsoo , Nassir Neema
Published: October 2012

A simple but efficient algorithm is proposed for finding the optimal path in an intermodal urban transportation network. The network is a general transportation network with multiple modes (auto, bus, rail, walk, etc.) divided into the two major categories of private and public, with proper transfer constraints. The goal was to find the optimal path according to the generalized cost, including private-side travel cost, public-side travel cost, and transfer cost. A detailed network model of transfers between modes was used to improve the accounting of travel times during these transfers. The intermodal path algorithm was a sequential application of specific cases of transit and auto shortest paths and resulted in the optimal intermodal path, with the optimal park-and-ride location for transferring from private to public modes. The computational complexity of the algorithm was shown to be a significant improvement over existing algorithms. The algorithm was applied to a real network within a dynamic traffic and transit assignment procedure and integrated with a sequential activity choice model.
Cost Functions for Strategies in Schedule-Based Transit Networks with Limited Vehicle Capacities
Authors: Rochau Normen , Nökel Klaus , Bell Michael G. H.
Published: October 2012

Passengers in congested transit networks need to understand capacity constraints of vehicles when network congestion prevents boarding a vehicle. A strategy concept was developed for schedule-based networks. The passenger is assumed to know the schedule, to be aware of the capacity constraints, and to realize the possibility of being unable to board a vehicle. Therefore, the passenger must plan for several what-if scenarios at each decision point of the trip. The concept of strategies in networks with capacity constraints was extended in a study. The strategy costs were defined in terms of a random variable. Properties of this random variable, mean value and variance, for example, were used to define new types of cost functions. This approach accounts for passengers' aversion to travel time variability and risk. In the literature, these ideas were originally developed for path choice models in private traffic but had not yet been applied to public transport. In the current study, the developed mean excess approach was adjusted so that it could be applied to public transport.
Gradient Projection Method for Simulation-Based Dynamic Traffic Assignment
Authors: Yang Inchul , Jayakrishnan R.
Published: October 2012

A gradient projection method is presented to solve the problem with dynamic traffic assignment. The gradient projection scheme is a feasible direction algorithm that operates directly in the space of path flows. The algorithm was applied to a simulation-based model for dynamic traffic assignment that used microscopic simulation for supply-side modeling. The formulation used link cost functions that were separate for moving and queuing vehicles on each link, so that the formulation could effectively capture the effects of traffic dynamic characteristics on each group, especially in arterial networks. The model and solution algorithm were applied to a small real-world network, and the performance was studied. The gradient projection algorithm avoided the problem of convergence to nonoptimal conditions shown by the prevalent method of successive averages and demonstrated significantly faster convergence.