Assessing the likelihood of secondary crashes on freeways with Adaptive Signal Control System deployed on alternate routes

Introduction: Reducing the likelihood of freeway secondary crashes will provide significant safety, operational and environmental benefits. This paper presents a method for assessing the likelihood of freeway secondary crashes with Adaptive Signal Control Systems (ASCS) deployed on alternate routes that are typically used by diverted freeway traffic to avoid any delay or congestion due to a freeway primary crash. Method: The method includes four steps: (1) identification of secondary crashes, (2) verification of alternate routes, (3) assessment of the likelihood of secondary crashes for freeways with ASCS deployed on alternate routes and non-ASCS (i.e. pre-timed, semi- or fully-actuated) alternate routes, and (4) investigation of unobserved heterogeneity of the likelihood of freeway secondary crashes. Four freeway sections (i.e., two with ASCS deployed on alternate routes and two non-ASCS alternate routes) in South Carolina are considered. Results and Conclusions: Findings from the logistic regression modeling reveal significant reduction in the likelihood of secondary crashes for one freeway section (i.e., Charleston I-26 E) with ASCS deployed on alternate route. Other factors such as rear-end crash, dark or limited light, peak period, and annual average daily traffic contribute to the likelihood of freeway secondary crashes. Furthermore, random-parameter logistic regression model results for Charleston I-26 E reveal that unobserved heterogeneity of ASCS effect exists across the observations and ASCS are associated with the reduction of the likelihood of freeway secondary crashes for 84% of the observations (i.e., primary crashes). Location of the primary crash on the freeway is observed to affect the benefit of ASCS toward freeway secondary crash reduction as the primary crash’s location determines how many upstream freeway vehicles will be able to take the alternate route. Practical Applications: Based on the findings, it is recommended that the South Carolina Department of Transportation (SCDOT) considers deploying ASCS on alternate routes parallel to freeway sections where high percentages of secondary crashes are found.     

LAKE CHAMPLAIN BASIN NONPOINT SOURCE PHOSPHORUS ASSESSMENT1

ABSTRACT: Existing land use data were used to estimate nonpoint source phosphorus loads to Lake Champlain (Vermont/New York/Quebec) in a loading function model that combined P concentration coefficients with regional hydrologic data. The estimates were verified against monitored loading data, then used to assess the relative magnitudes of contributions from major land uses and regions of the Lake Champlain Basin. The Basin is comprised of 62 percent forest, 28 percent agricultural land, 3 percent urban land, and 7 percent water. The best-fit model estimated an annual total P load of 457 mt/year, which did not differ significantly from the 458 metric tons/year measured for an average hydrologic year, and accurately predicted loads from major tributaries. Agriculture contributes 66 percent of the annual nonpoint source P load to Lake Champlain; urban and forest land contribute 18 percent and 16 percent, respectively. Because agricultural land contributes most nonpoint source P to Lake Champlain, load reduction effort must deal with agricultural sources. However, because the urban 3 percent of the basin contributes 18 percent of the estimated load, high load reduction efficiencies might be achieved by addressing urban sources. This assessment clearly demonstrated the relationship between land use and P loads in the Lake Champlain Basin, a prerequisite for policy-makers to endorse a P management strategy requiring changes in land use and management.     

The importance of spatial autocorrelation,extent and resolution in predicting forest bird occurrence

Concerns about declines in forest biodiversity underscore the need for accurate estimates of the distribution and abundance of organisms at large scales and at resolutions that are fine enough to be appropriate for management. This paper addresses three major objectives: (i) to determine whether the resolution of typical air photo-derived forest inventory is sufficient for the accurate prediction of site occupancy by forest birds. We compared prediction success of habitat models using air photo variables to models with variables derived from finer resolution, ground-sampled vegetation plots. (ii) To test whether incorporating spatial autocorrelation into habitat models via autologistic regression increases prediction success. (iii) To determine whether landscape structure is an important factor in predicting bird distribution in forest-dominated landscapes. Models were tested locally (Greater Fundy Ecosystem [GFE]) using cross-validation, and regionally using an independent data set from an area located ca. 250 km to the northwest (Riley Brook [RB]). We found significant positive spatial autocorrelation in the residuals of at least one habitat model for 76% (16/21) of species examined. In these cases, the logistic regression assumption of spatially independent errors was violated. Logistic models that ignored spatial autocorrelation tended to overestimate habitat effects. Though overall prediction success was higher for autologistic models than logistic models in the GFE, the difference was only significantly improved for one species. Further, the inclusion of spatial covariates did little to improve model performance in the geographically discrete study area. For 62% (13/21) of species examined, landscape variables were significant predictors of forest bird occurrence even after statistically controlling for stand-level variability. However, broad spatial extents explained less variation than local factors. In the GFE, 76% (16/21) of air photo and 81% (17/21) of ground plot models were accurate enough to be of practical utility (AUC > 0.7). When applied to RB, both model types performed effectively for 55% (11/20) of the species examined. We did not detect an overall difference in prediction success between air photo and ground plot models in either study area. We conclude that air photo data are as effective as fine resolution vegetation data for predicting site occupancy for the majority of species in this study. These models will be of use to forest managers who are interested in mapping species distributions under various timber harvest scenarios, and to protected areas planners attempting to optimize reserve function.     

Ecodynamics: Towards an evolutionary thermodynamics of ecosystems

This paper collects, with few minor formal changes, two of the latest scientific contributions ( [Tiezzi, 2006a] and [Tiezzi et al., 2010]) written by Prof. Enzo Tiezzi, where he introduced new concepts and tools to formalize and understand the role of thermodynamics in ecosystems theory.Particular attention is devoted to goal functions, to the relation of matter, energy, space and time and to the interdisciplinary approach connecting thermodynamics and biology. Entropy is discussed as a fundamental goal function in the far from equilibrium framework. The relationship between entropy, as a non-state function, and the state-function energy is stressed and discussed, at the light of the role of information. The theory of probability is also discussed in the light of new theoretical findings related to the role of events, also in terms of entropy and evolutionary thermodynamics.Confined Ontic Open Systems (COOS) represent the latest model proposed by Prof. Tiezzi based on his Ecodynamic theory, evolutionary thermodynamics, Ulanowicz's ontic. The model has a wide range of applications, including ecosystems, ecological economics, urban organization, the supra-molecular structure of water and global biosphere's models. The model is explained in terms of evolutionary thermodynamics and Jørgensen's ecosystems theory.     

Institutionalising social learning: Towards systemic and adaptive governance

This paper critically examines how public policy makers limit policy and other institutional design choices by a failure to appreciate (i) how situations may be characterised or framed; (ii) how practices that generate neologisms (invented terms or concepts) or reify (make into a thing) abstract concepts can displace understandings, and (iii) the epistemological bases of governance mechanism choices. An inquiry into the coining of the neologisms ‘wicked’ and ‘tame’ problems is reported and the implications for research and policy practice explored. As practices, neologising, reifying, categorising and typologising have unintended consequences – they remove us from the primary experiences and underlying emotions that provided the motivation for formulating these concepts in the first place. The failure to institutionalise the understandings and experiences that sit behind the invention of the terms ‘wicked’ and ‘tame’ problems (or similar framing choices such as ‘problematique’, ‘messes’, ‘lowland real-life swamps’, ‘resource dilemmas’ or ‘complex adaptive systems’) present systemic constraints to institutionalising social learning as an alternative yet complementary governance mechanism within an overall systemic and adaptive governance framework. Ultimately situations usefully framed as ‘wicked’,’ such as water managing and climate change are problems of relationship – of human beings with the biosphere. Re-framings, such as institutions as social technologies and other research and praxis traditions concerned with the breakdown of relationships may offer ways forward in the purposeful designing and crafting of more effective institutions.     

Residents’ Attitudes Towards Tourism in a Globally Important Agricultural Heritage Systems Pilot Site: a Case Study in China

Abstract

Globally Important Agricultural Heritage Systems (GIAHS) is a wide program to promote the conservation and adaptive management of such systems and their associated landscapes, biodiversity, knowledge systems and cultures. Rice-Fish Systems (RFS) in Longxian village of China, as a traditional agricultural system, was selected as one of the five pilot sites of GIAHS in 2005. Researchers have paid more attention to the dynamic conservation and adaptive management of RFS because it is under severe threats from global development challenges. Tourism is suggested to be brought into the RFS conservation program as an alternative industry. This paper presents a comparative study of residents in three types of farm household in Longxian, seeking attitudes to the RFS conservation and tourism development and ways in which such information may guide future strategies. Results show residents, belonging to the household type in which most family members are abroad, have the most positive attitudes to RFS conservation and tourism development; while residents, as other household type in which less than 50% of family members are abroad, are the least sensitive group in these three household types, due to the motivation of moving abroad weakening their enthusiasm to participate in the local activities. Implications are discussed in the context of how resident attitudes will affect the future management of GIAHS conservation and tourism development, and then measures are put forward to foster tourism cooperation and multistakeholders process establishment.     

Muscle Tetanus and Loading Condition Effects on the Elastic and Viscous Characteristics of the Thorax

Thoracic deformation under an applied load is an established indicator of injury risk, but the force required to achieve an injurious level of deformation currently is not understood adequately. This article evaluates how two potentially important factors, loading condition and muscle tensing, affect the structural response of the dynamically loaded thorax. Structural models of two human cadaver thoraxes and two porcine thoraxes were used to quantify the effects. The human cadavers, which represent anthropometric extremes, were subjected to anterior loading from (1) a 5.1-cm-wide belt oriented diagonally (i.e., seatbelt-like loading), (2) a 15.2-cm-diameter rigid hub, and (3) a 20.3-cm-wide belt oriented laterally (i.e., a distributed load). A structural model having the mathematical formulation of a quasilinear viscoelastic material model was used to model the elastic and viscous response, with ramp-hold tests used to determine the model coefficients. The effect of thoracic musculature was assessed using similar ramp-hold tests on the porcine subjects, each with and without forced muscle contraction. Even maximally contracted thoracic musculature is shown to have a minimal effect on the response, with similar elastic and viscous characteristics exhibited by each subject regardless of muscle tone. The elastic response is shown to be approximately a factor of three stiffer for diagonal belt loading and for this distributed loading condition than for the hub loading, indicating that the response is influenced most by the particular anatomical structures that are engaged and, secondarily, by the area of load application. Specifically, shoulder involvement is shown to have a strong influence. The force relaxation is found to be pronounced, but insensitive to the loading condition, with long-time force relaxation coefficients (G_∞) in the range of 0.1 to 0.3. The findings of this study provide restraint-specific guidelines for the force-deflection characteristics of both physical and computational thoracic models.     

Application of a cave inventory system to stimulate development of management strategies: the case of west-central Florida, USA

The active management of air-filled cave systems is virtually non-existent within the karst landscape of west-central Florida. As in every karst landscape, caves are important because they contain a wide variety of resources (e.g., biota, speleothems) and can act as direct connections between surface and subsurface hydrological processes, potentially exacerbating the pollution of groundwater. Before sound management policies can be drafted, implemented, and enforced, stakeholders must first have knowledge of the management requirements of each cave. However, there is an informational disconnect between researchers, stakeholders, and the recreational caving community. Here, we present a cave inventory system that simplifies the dissemination of resource knowledge to stakeholders so that cave management and protection policies can be drafted and implemented at the state and local level. We inventoried 36 caves in west-central Florida, located on both public and private land, and analyzed cave resource data to provide insights on cave sensitivity and disturbance using two standardized indices. The data revealed that both public and private caves exhibit a wide range of sensitivity and disturbance, and before management strategies can be drafted, the ownership of each cave must be considered. Our inventory geodatabase serves as a link between researchers, landowners, and the public. To ensure the conservation and protection of caves, support from county or state government, combined with cave inventory data, is crucial in developing sound management policy.     

Towards a relational paradigm in sustainability research,practice, and education

Relational thinking has recently gained increasing prominence across academic disciplines in an attempt to understand complex phenomena in terms of constitutive processes and relations. Interdisciplinary fields of study, such as science and technology studies (STS), the environmental humanities, and the posthumanities, for example, have started to reformulate academic understanding of nature-cultures based on relational thinking. Although the sustainability crisis serves as a contemporary backdrop and in fact calls for such innovative forms of interdisciplinary scholarship, the field of sustainability research has not yet tapped into the rich possibilities offered by relational thinking. Against this background, the purpose of this paper is to identify relational approaches to ontology, epistemology, and ethics which are relevant to sustainability research. More specifically, we analyze how relational approaches have been understood and conceptualized across a broad range of disciplines and contexts relevant to sustainability to identify and harness connections and contributions for future sustainability-related work. Our results highlight common themes and patterns across relational approaches, helping to identify and characterize a relational paradigm within sustainability research. On this basis, we conclude with a call to action for sustainability researchers to co-develop a research agenda for advancing this relational paradigm within sustainability research, practice, and education.