Analysis of train derailments and collisions to identify leading causes of loss incidents in rail transport of dangerous goods in Canada

The Canadian railway industry has improved safety performance in the last decade as measured by freight loss incidents per billion gross ton-miles. Further improvements in safety performance require a deeper analysis of the leading causes to identify weaknesses in implementing safety systems. In this paper, we classify the causes of railway loss incidents using a Safety Management System (SMS) framework to identify system weaknesses. The role of human factors is further analyzed through the Human Factors Analysis and Classification System (HFACS) approach. For this, we utilized data from 42 main track derailments and collisions involving the transport of dangerous goods in Canada between 2007 and 2018, which have been investigated by the Transportation Safety Board of Canada in detail. Associations between adjacent sub-categories of the HFACS framework are analyzed to identify any interdependency that exists between active and latent errors using a Chi-square test and Kruskal's lambda analysis. Furthermore, we implement the Decision-Making Trial and Evaluation Laboratory (DEMATEL) method and the Analytical Network Process (ANP) to identify causal relationships between different sub-categories of the HFACS framework and calculate the weighted influence of each sub-category on main track derailments and collisions. Finally, a comparison is made between this work and others', which have analyzed human factors in the railway industry. There is good agreement between the results of these studies that highlight the importance of supervisory and organizational factors in the prevention of railway loss incidents. Based on these findings, we make recommendations to reduce railway loss incidents.     

Analysis of the severity of vehicle-bicycle crashes with data mining techniques

Introduction: Although cycling is increasingly being promoted for transportation, the safety concern of bicyclists is one of the major impediments to their adoption. A thorough investigation on the contributing factors to fatalities and injuries involving bicyclist. Method: This paper designs an integrated data mining framework to determine the significant factors that contribute to the severity of vehicle-bicycle crashes based on the crash dataset of Victorian, Australia (2013–2018). The framework integrates imbalanced data resampling, learning-based feature extraction with gradient boosting algorithm and marginal effect analysis. The top 10 significant predictors of the severity of vehicle-bicycle crashes are extracted, which gives an area under ROC curve (AUC) value of 0.8236 and computing time as 37.8 s. Results: The findings provide insights for understanding and developing countermeasures or policy initiatives to reduce severe vehicle-bicycle crashes.     

管道分质供水消毒副产物及其安全性评价

消毒副产物是饮用水中应主要控制的毒害物。然而，管道分质供水中消毒副产物特征及污染水平很少研究。以某一管道分质供水工程为例，对其中消毒副产物进行了详细研究。研究结果表明，管道分质供水消毒副产物在量与质上与其源水自来水存在很大差别。在管道分质供水中消毒副产物量少，一般不到自来水的1／10，且主要是一些毒性较低、与供水管材有关的溶出物。据此计算出管道分质供水由消毒副产物引起的致癌风险性一般不到其源水的1／10，其安全性大大提高。     

Attitude to safety rules and reflexivity as determinants of safety climate

IntroductionWe present two studies that focus on the relationship between safety rules and the safety climate. It is expected that a reasoned acceptance, namely one based on an understanding of the bases for the rules and a collective management of the rules, should benefit the climate. Method: In an initial study (N = 202) employees replied to a questionnaire that measured the safety climate, the level of the relationship with the safety rules, and the understanding of their bases. The results highlighted the fact that a reasoned acceptance of the rules is associated with an understanding of their bases and predicts the level of safety. In a second study (N = 258) employees replied to a questionnaire measuring team reflexivity, the safety climate, and the level of relationship with the safety rules. We observed that collective management of the rules mediated the relation between team reflexivity and the safety climate. Results: The results are discussed from the point of view of their practical implications. Developing safety climate requires that operators are trained to understand the basis of safety rules and team reflexivity.     

Towards safer bicyclist responses to the presence of a truck near an urban loading zone: Analysis of bicyclist perceived level of comfort

IntroductionWhile sophisticated plans have been adopted nationally and globally to increase bicycling’s share of daily commutes, safety concerns have negatively impacted targeted bicycling growth. To investigate people’s preferences for bicycling in dense urban areas, it is important to recognize how bicycling perceived level of comfort (PLOC) is constructed and how it could relate to safe versus risky behavior while interacting with motorized modes of transportation. Method: To examine these issues, we analyzed results from an online survey with 342 participants. Structural Equation Modeling (SEM) was employed to systematically investigate the construct of bicycling PLOC and simultaneously analyze bicyclists’ responses to the presence of a truck in the adjacent lane near an urban loading zone. Results: SEM estimation results indicated that participants who said that they engaged in more frequent distracted bicycling reported lower PLOC. On the other hand, those who felt that road users were more lawful and predictable, and who had more bicycling experience, reported higher levels of PLOC. Participants who bicycled for commuting purposes, who made shorter trips, who bicycled more frequently, and who had more exposure to downtown bicycling also reported higher levels of PLOC. Finally, findings showed that higher PLOC was significantly associated with the choice of a safe, rather than a risky response to the presence of a truck, suggesting that a way to improve bicyclist safety would be to build an environment that could increase bicyclists’ PLOC.     

Fuzzy dynamic risk-based maintenance investment optimization for offshore process facilities

A methodology for maintenance planning is developed which helps in improving the reliability of the components and safety performance in process facilities. This methodology helps design an optimum safety maintenance investment plan by integrating the optimization techniques and a fuzzy dynamic risk-based method. Intuitionistic Fuzzy Analytic Hierarchy Process (IFAHP) is applied to deal with uncertain data. The proposed approach employs multi-experts’ knowledge which helps to optimize the maintenance investments. A separator system in an offshore process facility platform is selected as a case study to demonstrate the application of the proposed methodology. A practical example in the separator system is surveyed and potential failures and Basic Events (BEs) are identified. Finally, a risk-based maintenance plan is provided for future safety investment analysis. The results indicate that the developed methodology estimates the risk more accurately, which enhances the reliability of future process operations.     

Gas dispersion risk analysis of safety gap effect on the innovating FLNG vessel with a cylindrical platform

While the effect of the safety gap on explosions is well known, little has been carried out to evaluate the effect of the safety gap on dispersion of gas releases, this paper evaluates the effect of safety gap on gas dispersion for a cylindrical Floating Liquefied Natural Gas (FLNG) vessel. The realistic ship-shaped and circular FLNG platforms are established and used for the detailed CFD based analysis; rather than the structural and hydrodynamics advantages of mobility, stability and cost efficiency etc., this study aims to investigate the safety of gas dispersion on the cylindrical FLNG and compare the safety gap effects on different configurations. A series of different safety gap configurations are evaluated for gas dispersion occurring in near field for the traditional FLNG while both near field and far field gas dispersion simulations are conducted on the cylindrical one. The overall results indicate that the safety gap is effective in reducing the gas cloud size in both FLNG configurations, however, when it comes to the gas dispersion in the far field against the leakage point, the safety gap increases the gas cloud size in the cylindrical FLNG vessel on the contrary.