Air Traffic Management accident risk. Part 2: Repairing the deficiencies of ESARR4

This is a critique of ESARR4 and its main supporting documents. ESARR4 is the Eurocontrol Safety Regulatory Requirement Number 4 [Eurocontrol safety regulatory requirement ESARR4, Edition 1.0., Eurocontrol, Safety Regulation Commission, Brussels, 2001]: ‘Risk assessment and mitigation in ATM’, ATM standing for Air Traffic Management. It is demonstrated that ESARR4 and its supporting documents are defective. There is a lack of clarity about responsibilities for ATM safety. The claims ESARR4 etc. make for its proposed methodologies are overstated—not supported by sound evidence from real world hazard analysis. Serious negative effects from this defective document include mis-allocation of scarce safety resources and the diversion of attention away from real safety improvements—wasteful of regulators’ and managers’ time. Suggestions are made for repairing these deficiencies. The most important underlying change would be a refocusing on practical safety assessment based on methods that have already demonstrated their merits.     

Quantification of risk perception: Development and validation of the construction worker risk perception (CoWoRP) scale

Introduction: The construction sector is leading in the number of accidents and fatalities; risk perception is the key to driving these numbers. Previous construction safety studies on risk perception quantification have not considered affective risk perception of construction workers or conducted comprehensive reliability and validity testing. Thus, this study aims to fill this need by developing a psychometrically sound instrument – the Construction Worker Risk Perception (CoWoRP) Scale – to assess the risk perception of construction workers. Method: Four phases of scale development, namely, item development, factor analysis, reliability assessment, and validity assessment were conducted with the collection and testing of data from a group (n = 469) of voluntary construction workers in Hong Kong. Results: The CoWoRP Scale with 13 items was shown to have acceptable test–retest reliability, internal consistency reliability, as well as content, convergent, discriminant, and criterion-related validity. Also, the CoWoRP Scale was affirmed to have three dimensions of worker risk perception, namely risk perception – probability, risk perception – severity, risk perception – worry and unsafe. These three dimensions of worker risk perception were negatively correlated with their risk-taking behavior. Conclusions: The CoWoRP Scale is a reliable and valid instrument for measuring the risk perception of construction workers and is expected to facilitate the construction safety studies that take risk perception of construction workers into account. Practical applications: The CoWoRP Scale could serve as an aptitude test to identify the characteristics of construction workers most likely to perceive lower risk in risky work situations. In turn, this information could help safety management provide safety training programs to those workers to enhance their risk perception and thereby minimizing their risk-taking behavior, reducing unnecessary training costs, and improving the construction safety performance.     

A case study: An explosion in a milk spray dryer,CAPSA, NW Spain

European Standard EN 14491 (2006): “Dust explosion venting protective systems”, based on German Standard VDI 3673 (2002): “Pressure venting of dust explosions”, Verein Deustcher Ingenieure, specifies the basic design requirements for the selection of dust explosion venting protection systems.In this study an investigation into the efficiency of venting surfaces in accordance with Standard EN 14491 has been undertaken to check the validation of the same. Thus, the application of the standard to an actual case of an explosion in a milk spray dryer has been studied, taking into consideration the explosive characteristics of products treated in this type of installation and their venting requirements.The results obtained indicate that, in specific situations – such as the effects of turbulence, particularly in the cone, or dust layer self-ignition – the European Standard could underestimate the venting surface requirements needed to alleviate possible excess internal pressure in order to avoid injury or structural damage to spray dryers.     

Analyzing the safety impact of longer and heavier vehicles circulating in the European market

Introduction: The European Union (EU) has developed different strategies to internalize the costs of excessive motor traffic in the road freight transport sector. One of these is a relaxation of restrictions on the size and load capacity of trucks that circulate between member States and a proposal has been made for Longer and Heavier Vehicles (LHVs) to be allowed to circulate across borders. LHVs are the so-called “megatrucks” (i.e., trucks with a length of 25 meters and a weight of 60 tonnes). Megatrucks have allowed to circulate for decades in some European countries such as Norway, Finland, and Sweden, world leaders in traffic accident prevention, although the impact that cross-border traffic would have on road safety is still unknown. Methods: This article provides an econometric analysis of the potential impact on road safety of allowing the circulation of “megatrucks” throughout the EU. Results: The findings show that countries that currently allow megatrucks to circulate present lower traffic accident and fatality levels, on average. Conclusions: The circulation of this type of vehicle is only advisable in countries where there is a certain degree of maturity and demonstrated achievements in the field of road safety. Practical applications: European countries that have allowed megatruck circulation obtaining better road safety outcomes in terms of accidents, although the accident lethality rate seems to be higher. Consequently, introducing megatruck circulation requires a prior proper preparation and examination.     

A data mining approach to deriving safety policy implications for taxi drivers

Introduction: Traffic safety issues associated with taxis are important because the frequency of taxi crashes is significantly higher than that of other vehicle types. The purpose of this study is to derive safety implications to be used for developing policies to enhance taxi safety based on analyzing intrinsic characteristics underlying the cause of traffic accidents. Method: An in-depth questionnaire survey was conducted to collect a set of useful data representing the intrinsic characteristics. A total of 781 corporate taxi drivers participated in the survey in Korea. The proposed analysis methodology consists of two-stage data mining techniques, including a random forest method, with data that represents the working condition and welfare environment of taxi drivers. In the first stage, the drivers’ intrinsic characteristics were derived to classify four types of taxi drivers: unspecified normal, work-life balanced, overstressed, and work-oriented. Next, priority was determined for classifying high-risk taxi drivers based on factors derived from the first analysis. Results: The derived policies can be categorized into three groups: ‘the development of new policies,’ ‘the improvement of existing policies,’ and ‘the elimination of negative factors.’ Establishing a driving capability evaluation system for elderly drivers, developing mental health management programs for taxi drivers, and inspecting the taxi's internal conditions were proposed as new policies. Improving the driver's wage system, supporting the improvement of rest facilities, and supporting the installation of security devices for protecting taxi drivers are methods for improving existing policies to reinforce the traffic safety of taxi drivers. Last, restricting overtime work for taxi drivers was proposed as a policy to eliminate negative factors for improving taxi traffic safety. Practical Applications: It is expected that by devising effective policies using the policy implications suggested in this study, taxi traffic accidents can be prevented and the quality of life of taxi drivers can be improved.     

Operator-centred local error management in air traffic control

Introduction: A large number of air traffic control occurrences take place without resulting in loss of separation between aircraft. Unfortunately such occurrences are seldom reported and therefore not used for disclosing system weaknesses, such as inappropriate methods and procedures.The ATCC (Air Traffic Control Centre) Malmoe made a trial with local reporting of “learning occurrences”. The trial was ATCO-(Air Traffic Controller) centred. The study objectives were to evaluate if ATCOs would start to report after a defined training and marketing effort, if they could identify system weaknesses, if concrete actions for safety improvement would be taken as a result of the trial and to what extent expert support was necessary.Method and material: The trial period was eight months. The ATCO report would be made on a simple form, available on site. These reports would then be analysed in groups and the marketing and feedback efforts would be co-ordinated by the local flight safety group.Results: 43 reports were filed and analysed during the trial period. The initial motivational training and marketing was considered adequate. During the group discussions, the ATCOs identified system weaknesses within 40 of the reports. The resulting safety improvement actions included: the ATCC unit becoming more active in contacting the pilots and airline companies, the renaming of some waypoints (due to name similarities), the implementation of safer procedures when relieving ATCOs, the training of ATCOs in cockpit flight management systems, and the initiation of a research project primarily concerned with ATCO mental overload.Expert support was required in the beginning to help ATCOs focus on the system rather than on the individual.     

Unintended consequences of management strategies for improving labor productivity in construction industry

Introduction: Labor productivity and safety are important topics in the construction industry. Even so, the literature provides little information for project managers trying to determine how management strategies designed to improve labor productivity impact safety. Method: This research addresses the gap by measuring the impact of two groups of management strategies that involve human resource related management strategies and construction related management strategies related to safety performance in construction projects. Data were collected from 111 general construction projects through the survey. Results: The results show that the relationship between the implemented management strategies and safety performance is nuanced with ‘Communication’ harming safety performance while implementation of ‘Labor Management,’ ‘Supervision and Leadership,’ ‘Planning’ and ‘Management of Construction’ strategies improve the level of safety performance. This study took a further step by measuring the impact of the interactions between the two groups of management strategies on safety performance. The results show that the interactions of construction and human related management strategies are not always in the favor of safety. Practical Applications: This paper adds to the literature on the relationship between productivity and safety in the construction industry. The research findings can assist project managers to improve labor productivity without harming the safety of laborers unintentionally.     

How do organizational practices relate to perceived system safety effectiveness? Perceptions of safety climate and co-worker commitment to safety as workplace safety signals

Introduction: Integrating safety climate research with signaling theory, we propose that individual perceptions of safety climate signal the importance of safety in the organization. Specifically, we expect that three work-related organizational practices (training effectiveness, procedure effectiveness, and work pressure) relate to the broader risk control system in the workplace via individual perceptions of safety climate as a broad management signal. Further, we expect this broad management signal interacts with a local environmental signal (co-worker commitment to safety) to amplify or diminish perceived system safety effectiveness. Method: In a field study of oil and gas workers (N = 219; Study 1), we used mediation modeling to determine the relationships between work-related organizational practices, perceived safety climate, and perceived safety system effectiveness. In a field study of railway construction workers (N = 131; Study 2), we used moderated mediation modeling to explore the conditional role of co-worker commitment to safety. Results: We found that training effectiveness, procedure effectiveness, and work pressure predicted perceived system safety effectiveness indirectly via perceived safety climate (Studies 1 and 2) and that these indirect paths are influenced by co-worker commitment to safety (Study 2). Conclusions: Findings suggest that perceived safety climate is driven in part by work practices, and that perceived safety climate (from managers) and co-worker commitment to safety (from the local environment) interact to shape workplace safety system effectiveness. Practical applications: The insight that training, procedures, and work pressure are meaningful predictors of perceived safety climate as a signal suggests that organizations should be cognizant of the quality of work-related practices for safety. The insight we offer on the competing versus complimentary nature of managerial safety signals (perceived safety climate) and co-worker safety signals (co-worker commitment to safety) could also be used by safety personnel to develop safety interventions directed in both areas.     

Measuring safety culture in a research and development centre: A comparison of two methods in the Air Traffic Management domain

This paper describes two safety surveys carried out in an Air Traffic Management Research and Development centre (EUROCONTROL Experimental Centre). The paper discusses the differences and similarities between the two tools with regard to their development, the method of conducting the surveys, the results and their implications. It has been estimated that about 50%¹ to 60%² of accidents and incidents appear to have their roots in the design and development process, and since this is the core business of the EEC, it was deemed necessary to investigate the maturity of safety at the EEC. The challenge for the EUROCONTROL Experimental Centre (EEC) was to develop a tool that is relevant to a research and development environment with the objectives of (i) identifying areas of weakness in the safety culture of the organization (ii) helping in developing a Safety Management System. The first objective was addressed by developing a Safety Culture Survey (SCS) tool and surveying the EEC (March, 2003). The second objective was addressed by customizing an existing (SMS) survey tool (RD) for the R&D environment. The SCS is based on traditional measures adapted to ATM and then to R&D, and the River Diagram (RD) is more of a safety management survey, adapted from other industries and already applied to HQ (EUROCONTROL Head Quarters) to examine their commitment to safety. Nevertheless, the two surveys have been compared to see where they agree and where they ‘dissociate’. Overall, the SCS has a broader focus on “softer issues”, i.e. more complex issues of ‘trust in management’. Diagnostically, the River Diagram survey helps the practitioner develop SMS implementation plans more readily than the Safety Culture survey.     

Risk analysis in research environment – Part II: Weighting Lab Criticity Index using the Analytic Hierarchy Process

A new methodology for risk analysis, namely Laboratory Assessment and Risk Analysis – LARA, is proposed in the companion paper to assess risks in research/academia environment. The core of this methodology relies on defining the adequate role player factors to assess risks in research environment and their mathematical combination to quantify and assess the risk. Quantitative outcome of the analysis results in a Lab Criticity Index – LCI, constructed as a rather comprehensive function of probability, severity, risk worsening factors, research specificities and Hazard Detectability. Even though the LCI model can be used at this stage, its “surjective” and “linear” properties were outlined; the non differentiation between LCI factors remains to be solved.The present article addresses this problematic, bringing a solution based on a Multicriteria Decision Making – MCDM modeling, namely Analytic Hierarchy Process – AHP. This leads to a refined criticity index being “bijective” and unique for every combination of factors.A preliminary risk assessment based on the LARA methodology is discussed for a research lab working with lasers.     

Using a psychological contract of safety to predict safety climate on construction sites

Introduction: The fact that safety climate impacts safety behavior and delivers better safety outcomes is well established in construction. However, the way workers safety perception is inclined and developed is still unclear. Method: In this research, the influence of supervisors' developing safety climate and its impact on workers' safety behavior and their conceptualization of safety is explored through the lens of the ‘Psychological Contract’ (PC). More specifically, it is argued that ‘Psychological Contract of Safety’ (PCS) is a vital factor in explaining how workers attach meaning to a supervisor behavior. Extant research suggests: (a) safety climate is based on the perception of workers regarding safety; and (b) PCS is based on perceived mutual obligations between workers and supervisors. As a result, this research argues that if PCS or mutual obligations between workers and supervisors are fulfilled, then safety climate of the workers will be positively influenced. A model is presented depicting PCS as an alternative intervention in understanding how safety climate could be influenced and predicted by the level of fulfillment of mutual safety obligations. Using Structural Equation Modeling (SEM) the model of the PCS is validated with data collected from a mega-construction project in Australia. Results: The results suggest that to have a positive and strong safety climate, top-level managers must ensure that mutual safety obligations between supervisor and workers are fulfilled. This enables the PCS to be introduced as a new ‘predictor’ of safety climate. Practical applications: The novel outcome of the research could be considered as a management intervention to modify supervisors' behavior to produce better safety outcomes.     

Taking account of the role of safety on vehicle choice using a new generation of discrete choice models

In attitudinal studies safety often appears as an important attribute desired by consumers when buying a new car (Ben-Akiva and Lerman, 1985). However, economic models of vehicle choice usually neglect the role of safety. On the one hand, to capture the qualitative nature of safety and variables related to safety one should consider safety as an underlying construct in a context of latent variable models. The problem is that psychometric models that make use of latent variables do not necessarily provide a complete understanding of agent behavior and may lead to poor predictive power. On the other hand, discrete choice models - although a powerful tool to explain decision making based on utility maximization behavior - fail to include qualitative factors as explanatory variables of the decision process.In this paper, we explore how to model safety through a new generation of discrete choice models which simultaneously consider both a standard discrete choice model and latent causal variables. Using stated preference data concerning purchase intentions of low-emission vehicles in Canada, we test a hybrid choice model to explain consumers’ preferences for safety. Based on the results as well as on the hybrid choice modeling approach, we outline a general framework for the correct modeling of the adoption of safer vehicles and appreciation of safety equipment.     

Improving workplace safety by thinking about what might have been: A first look at the role of counterfactual thinking

Introduction: Information processing theories of workplace safety suggest that cognition is an antecedent of safety behavior. However, little research has directly tested cognitive factors as predictors of workplace safety within organizational psychology and behavior research. Counterfactuals (cognitions about “what might have been”) can be functional when they consist of characteristics (e.g., “upward’ – focusing on better outcomes) that alter behavior in a manner consistent with those outcomes. This field study aimed to examine the influence of counterfactual thinking on safety behavior and explanatory mechanisms and boundary conditions of that relationship. Method: A sample of 240 medical providers from a hospital in China responded to three surveys over a four-month time frame. Results: Results showed that upward counterfactuals were positively related to supervisor ratings of safety compliance and participation. These relationships were mediated by safety knowledge but not by safety motivation. Upward counterfactuals were more strongly related to safety behavior and knowledge than downward counterfactuals. As expected, safety locus of control strengthened the mediating effects of safety knowledge on the relationship between upward counterfactuals and safety behavior. Conclusions and Practical Applications: The findings demonstrated that counterfactual thinking is positively associated with safety behavior and knowledge, thus expanding the variables related to workplace safety and laying some initial groundwork for new safety interventions incorporating counterfactual thinking.     

Air Traffic Management accident risk. Part 1: The limits of realistic modelling

The prime goal of the Air Traffic Management (ATM) system is to control accident risk. Some key questions are posed, including: What do design safety targets really mean and imply for risk modelling? In what circumstances can future accident risk really be modelled with sufficient precision? If risk cannot be estimated with precision, then how is safety to be assured with traffic growth and operational/technical changes? This paper endeavours to answer these questions by an analysis of the nature of accidents, causal factors and practical collision risk modelling. The main theme is how best to combine sound safety evidence and real-world hazard analysis in a coherent and systematic framework.     

Work-safety tension, perceived risk, and worker injuries: a meso-mediational model

IntroductionWork-safety tension arises when workers perceive that working safely is at odds with effectively doing their jobs. We proposed that workers’ perceptions of work-safety tension would be associated with higher levels of perceived risk, which would, in turn, relate to worker injuries on the job.MethodGrocery store workers (n = 600) completed an online survey and organizational worker injury reports were obtained for a two-year period following the survey. Survey results were linked to subsequent worker injuries using hierarchical generalized linear modeling.ResultsWe found support for the proposed meso-mediation model: department work-safety tension predicted subsequent worker injuries, partially through an association with workers’ risk perceptions.ConclusionsSafety researchers and consultants and organizational leaders should look beyond typically-examined safety climate constructs, such as management commitment to safety, and pay particular attention to workers’ perceptions of work-safety tension.     

Where to focus? Insights from safety personnel and external safety consultants on lessons learned about safety climate interventions – A qualitative approach

Introduction: Safety climate is important for promoting workplace safety and health. However, there is a dearth of empirical research on the effective ways of planning, designing, and implementing safety climate interventions, especially regarding what is going to be changed and improved. To address this gap, the present study sought to extract a comprehensive pool of compiled suggestions for safety climate intervention based on qualitative interviews with professionals in occupational safety and health management from potentially hazardous industries. Method: A series of systematic semi-structured interviews, guided by a comprehensive sociotechnical systems framework, were conducted with company safety personnel (n = 26) and external safety consultants (n = 15) of 21 companies from various industries. The taxonomy of five work system components of the sociotechnical systems approach served as overarching themes, representing different areas of improvement in an organization for occupational safety and health promotion, with an aim of enhancing safety climate. Results: Of the 36 codes identified, seven codes were based on the theme of external environment work system, four were based on the theme of internal environment work system, five were based on the theme of organizational and managerial structure work system, 14 codes were based on the theme of personnel subsystem, and six were based on the theme of technical subsystem. Conclusions: Safety climate intervention strategies might be most commonly based upon the principles of human resource management (i.e., codes based on the personnel subsystem theme and organizational and managerial structure work system theme). Meanwhile, numerous attributes of external/internal environment work system and technical subsystem can be jointly improved to bolster safety climate in a holistic way. Practical Applications: More systematic and organized management of safety climate would be available when various interrelated codes pertinent to a given context are carefully considered for a safety climate intervention.     

Tipping point: The narrow path between automation acceptance and rejection in air traffic management

Capacity limits on the air traffic management (ATM) system are of global concern. One solution to increase the efficiency of existing ATM system is through the implementation of advanced automation. However, past experience suggests ATCOs are selective and critical about the forms of automation they are given. Therefore, this study aimed to determine if a threshold or tipping point exists, a point after which users (Air Traffic Control Operators; ATCOs) of automation are no longer willing to accept or cooperate with the automation. 500 Air Traffic Control Operators completed an on-line survey that comprised a series of demographic questions as well as two hypothetical but plausible futuristic air traffic management tools. Each tool contained seven different situations involving different levels of automation involvement ranging from fully manual operation to fully automated. Participants were asked to rate on a five point Likert scale the extent to which they agreed with the statements describing their interaction with the new tools. The results revealed a ‘tipping point’ in automation acceptance/rejection reflecting the point where the applied level of automation shifted the locus of decision-making away from the operator. The results are discussed from a theoretical and applied perspective.     

Human Performance Cognitive-Behavioral Modeling: A Benefit for Occupational Safety

Human Performance Modeling (HPM) is a computer-aided job analysis software methodology used to generate predictions of complex humanautomation integration and system flow patterns with the goal of improving operator and system safety. The use of HPM tools has recently been increasing due to reductions in computational cost, augmentations in the tool’s fidelity, and usefulness in the generated output. An examination of an Air Man-machine Integration Design and Analysis System (Air MIDAS) model evaluating complex human-automation integration currently underway at NASA Ames Research Center will highlight the importance to occupational safety of considering both cognitive and physical aspects of performance when researching human error.