The Experts below are selected from a list of 279 Experts worldwide ranked by ideXlab platform
Eric T. Donnell - One of the best experts on this subject based on the ideXlab platform.
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Safety performance functions for horizontal curves and tangents on two lane, two way rural roads.
Accident; analysis and prevention, 2018Co-Authors: Jeffrey P. Gooch, Vikash V. Gayah, Eric T. DonnellAbstract:Horizontal curves on two-way, two-lane rural roads pose critical Safety concerns. Accurate prediction of Safety performance at these locations is vital to properly allocate resources as a part of any Safety Management Process. The current method of predicting Safety performance on horizontal curves relies on the application of a Safety performance function (SPF) developed using only tangent sections and adjusting this value using a crash modification factor (CMF). However, this Process inherently assumes that Safety performance on curves and tangent sections share the same general functional relationships with variables included in the SPF, notably traffic volumes and segment length, even though research suggests otherwise. In light of this, the goal of this paper is to systematically study the relationship between Safety performance and traffic volumes on horizontal curves of two-lane, two-way rural roads and to compare this to the Safety performance of tangent sections. The propensity scores-potential outcomes framework is used to help ensure similarity between tangent and curve sections considered in the study, while mixed-effects negative binomial regression is used to quantify Safety performance. The results reveal that Safety performance on horizontal curves differs significantly from that on tangent sections with respect to both traffic volumes and segment length. Significant differences were also found between the Safety performance on tangents and curves relative to other roadway features. These results suggest that curve-specific SPFs should be considered in the next edition of the Highway Safety Manual.
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Application of propensity scores and potential outcomes to estimate effectiveness of traffic Safety countermeasures: Exploratory analysis using intersection lighting data.
Accident; analysis and prevention, 2012Co-Authors: Lekshmi Sasidharan, Eric T. DonnellAbstract:More than 5.5 million police-reported traffic crashes occurred in the United States in 2009, resulting in 33,808 fatalities and more than 2.2 million injuries. Significant funds are expended annually by federal, state, and local transportation agencies in an effort to reduce traffic crashes. Effective Safety Management involves selecting highway and street locations with potential for Safety improvements; correctly diagnosing Safety problems; identifying appropriate countermeasures; prioritizing countermeasure implementation at selected sites; and, evaluating the effectiveness of implemented countermeasures. Accurate estimation of countermeasure effectiveness is a critical component of the Safety Management Process. In this study, a statistical modeling framework, based on propensity scores and potential outcomes, is described to estimate countermeasure effectiveness from non-randomized observational data. Average treatment effects are estimated using semi-parametric estimation methods. To demonstrate the framework, the average treatment effect of fixed roadway lighting at intersections in Minnesota is estimated. The results indicate that fixed roadway lighting reduces expected nighttime crashes by approximately 6%, which compares favorably to other, recent lighting-Safety research findings.
Zoran Ž. Avramović - One of the best experts on this subject based on the ideXlab platform.
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Safety of railway transport of dangerous cargo
JTTTP - JOURNAL OF TRAFFIC AND TRANSPORT THEORY AND PRACTICE, 2019Co-Authors: Dragutin Jovanović, Zoran Ž. Avramović, Siniša Arsić, Miloš ArsićAbstract:By railway, according to its technological characteristics, the respective amounts of dangerous cargo are being transported. Numerous hazards for people, assets and environment during the dangerous railway cargo transport Processes, are expressed in the case of an extraordinary case or any other misManagement, where the transport becomes risky, but the same risk is an opportunity for improvements if it’s recognized on the way and measures are defined and established for its Management. For achieving Safety goals within transport of dangerous cargo, it means minimizing the number of extraordinary circumstances and overall consequences with undisturbed transport Process support, it’s necessary to manage and to work constantly on the Safety improvements. In the Safety Management Process, the whole railroad staff must take part according to the work duties, responsibilities and competences.
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Focus Areas and Measures to Improve Road Traffic Safety at the Local Level
Management Science, 2017Co-Authors: Milenko Čabarkapa, Zoran Ž. AvramovićAbstract:Earlier approach to road traffic Safety system proceeded from the assumption that the driver must adapt to the traffic system. Modern approach to road traffic Safety system recognizes that traffic system must be adapted to a traffic participant: drivers, pedestrians, particularly vulnerable participants: children, elderly, persons with reduced mobility. The starting point is the acceptance of human error and vulnerability of the human body, and in accordance with that, understanding that traffic accidents cannot be completely avoided, but the death and severely injuring of traffic participants may be reduced. For this purpose, the control function of road traffic Safety system promotes interventions, by whose implementation results are achieved. Road traffic Safety system Management, in addition to national, must take place at the local level. Although the local system of road traffic Safety can be, in functional terms, set analogous to national system, its frames are much narrower and thus put much more specific and evolving demands on local road Safety Management for adjusting the local Management system to local conditions. In this context, local traffic Safety goals should focus on areas where the effect of local intervention improves traffic Safety. This paper has developed the concept of traffic Safety Management Process at the local level, encouraged by the Global Plan of the UN Decade of Action for Road Safety 2011-2020, which is modeled by conversion National Pillars Activities in Local Focus Areas and Measures and based on the analysis of general statistics on traffic accidents and in-depth analysis of traffic accidents with killed and seriously injured persons on local roads. With a focus on results to improve traffic Safety in local communities of Montenegro, three areas are identified and twenty measures in them, whose implementation would obtain the greatest possible impact in adapting local road traffic Safety system to road users, which is a precondition for improving traffic Safety in the local community.
Stephen D. Boyles - One of the best experts on this subject based on the ideXlab platform.
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Optimal funding allocation strategies for Safety improvements on urban intersections
Transportation Research Part A: Policy and Practice, 2015Co-Authors: Sabyasachee Mishra, Sushant Sharma, Mihalis M. Golias, Stephen D. BoylesAbstract:Urban intersections crashes cause significant economic loss. The Safety Management Process undertaken by most states in the United States is referred to as Highway Safety Improvement Program and consists of three standardized steps: (i) identification of critical crash locations, (ii) development of countermeasures, and (iii) resource allocation among identified crash locations. Often these three steps are undertaken independently, with limited detail of each step at the state planning agencies. The literature review underlines the importance of the third step, and the lack of sophisticated tools available to state planning agencies for leveraging information obtained from the first two steps. Further, non-strategic approaches and unavailability of methods for evaluating policies may lead to sub-optimal funding allocation. This paper overcomes these limitations and proposes multiple optimal resource allocation strategies for improvements at urban intersections that maximize Safety benefits, under budget and policy constraints. Proposed policy measures based on benefits maximization (economic competitiveness), equitable allocation (equity), and relaxation of mutually exclusiveness (multiple alternatives at one location) produce significantly different alternative and fund allocation. The proposed models are applied to selected intersections in four counties of southeast Michigan. Results reinforce the applicability of the strategies/policies and tools developed in this paper for Safety project funding allocation on critical urban intersections.
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Economic Competitiveness and Equity-Based Safety Improvement Allocation Model for Urban Intersections
2014Co-Authors: Sabyasachee Mishra, Sushant Sharma, Mihalis M. Golias, Stephen D. BoylesAbstract:Economic competitiveness and equity can be two competing objectives while allocating funds for implementation of Safety alternatives on urban intersections. One of the critical phase of current Safety Management Process (hazard elimination program) undertaken by most states is resource allocation among identified crash locations. Literature underlines the importance of this phase and lack of sophisticated tools available to state planning agencies for evaluating federal and state policies. The study overcomes this limitation by proposing an optimization based resource allocation model that maximizes Safety benefits, subjected to budget and policy constraints. The proposed model incorporates economic competitiveness in the allocation and distributes improvements to urban intersections such that maximum economical benefits are obtained from crash savings. However, results show that while economic competitiveness leads to optimal benefits, resource allocation is inequitable. Hence equity based models are developed by adding two policy options: equity in opportunity and equity in outcome. The resource allocation model is solved using sequential quadratic programming. The model is applied to crash prone intersections in four counties of southeast Michigan. The proposed model is generic and scalable, with flexibility in including policy options often considered by state and local agencies.
Milenko Čabarkapa - One of the best experts on this subject based on the ideXlab platform.
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Focus Areas and Measures to Improve Road Traffic Safety at the Local Level
Management Science, 2017Co-Authors: Milenko Čabarkapa, Zoran Ž. AvramovićAbstract:Earlier approach to road traffic Safety system proceeded from the assumption that the driver must adapt to the traffic system. Modern approach to road traffic Safety system recognizes that traffic system must be adapted to a traffic participant: drivers, pedestrians, particularly vulnerable participants: children, elderly, persons with reduced mobility. The starting point is the acceptance of human error and vulnerability of the human body, and in accordance with that, understanding that traffic accidents cannot be completely avoided, but the death and severely injuring of traffic participants may be reduced. For this purpose, the control function of road traffic Safety system promotes interventions, by whose implementation results are achieved. Road traffic Safety system Management, in addition to national, must take place at the local level. Although the local system of road traffic Safety can be, in functional terms, set analogous to national system, its frames are much narrower and thus put much more specific and evolving demands on local road Safety Management for adjusting the local Management system to local conditions. In this context, local traffic Safety goals should focus on areas where the effect of local intervention improves traffic Safety. This paper has developed the concept of traffic Safety Management Process at the local level, encouraged by the Global Plan of the UN Decade of Action for Road Safety 2011-2020, which is modeled by conversion National Pillars Activities in Local Focus Areas and Measures and based on the analysis of general statistics on traffic accidents and in-depth analysis of traffic accidents with killed and seriously injured persons on local roads. With a focus on results to improve traffic Safety in local communities of Montenegro, three areas are identified and twenty measures in them, whose implementation would obtain the greatest possible impact in adapting local road traffic Safety system to road users, which is a precondition for improving traffic Safety in the local community.
Frank Wen - One of the best experts on this subject based on the ideXlab platform.
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Exploring the modeling and site-ranking performance of Bayesian spatiotemporal crash frequency models with mixture components.
Accident; analysis and prevention, 2019Co-Authors: Wen Cheng, Gurdiljot Singh Gill, Yongping Zhang, Frank WenAbstract:Abstract The current study introduces the flexible approach of mixture components to model the spatiotemporal interaction for ranking of hazardous sites and compares the model performance with the conventional methods. In case of predictive accuracy based on in-sample errors (posterior deviance), the Mixture-5 demonstrated superior performance in majority of the cases, indicating the advantage of mixture approach to accurately predict crash counts. LPML (log pseudo marginal likelihood) was also calculated as a cross-validation measure based on out-of-sample errors and this criterion also established the dominance of Mixture-5, further reinforcing the superiority of the mixture approach from different perspectives. The site ranking evaluation results demonstrated the advantages of adopting the mixture approach. In terms of total rank difference (TRD) results, there were several discrepancies between the two approaches, suggesting that two approaches designate unsafe sites differently. Another site ranking criterion, site consistency test (SCT), was employed to explore the difference in identification of unsafe sites based on two datasets: estimated crash count (traditional) and the spatial variability across time. The advantage of mixture models to act as a complimentary approach for site ranking was revealed by the spatial variability SCT results. The method consistency test (MCT) results also indicate the advantages of mixture models over the Base one. These findings suggested that mixture approach may prove helpful in the network screening step of Safety Management Process to identify sites which may turn unsafe in the future and escape the detection from traditional methods.
