Risky Conditions Research Articles

Factors affecting motorcyclists’ behavior in car-following condition

Car-following (CF) maneuver plays an important role in both traffic flow analysis and road safety assessment. However, many studies on this issue have focused on the drivers’ behaviour, neglecting the different driving behaviour of the motorcycle riders and the vulnerability of this type of user. The aim of the present paper is to analyse the factors affecting the riders’ behaviour in CF condition, by using two surrogate safety indicators, Time Headway (TH) and Time To Collision (TTC). A field experiment was conducted to collect data. Twenty young motorcyclists participated in the study driving their own motorcycles, which were instrumented with a camera and a global positioning system device (GPS). A digital image processing algorithm was used to obtain CF related indicators. The results of the study showed that Time Headway (TH) and Time To Collision (TTC) are independent of each other, extending the result obtained in the literature for the four wheeled vehicles to the motorcycles. TTC and TH were therefore analyzed separately. As for TTC, it was observed that only in few cases (0.8%) the riders were found in risky condition (TTC < 5 s), confirming the role of this parameter for the detection of an impending risk. On the other hand, TH gives information about a potentially risky situation, and 99% of the riders were found in such condition (TH < 2 s). Due to the few cases in TTC risky conditions, only TH was further modelled by using the hazard-based duration analysis. Accelerated Failure Time (AFT) model specification was used, and the Weibull distribution provided the best fit of the data. The model identified four covariates affecting TH and all of them had the effect of reducing TH, increasing the collision risk. The time spent on CF condition, the speed of the motorcycle, the willingness of overtaking and the engine size of the motorcycle were the factors that reduced TH.The findings of this study could be considered in the development of microsimulation models; the factors that were found affecting the motorcyclists’ behavior in car-following condition could be considered for a more realistic simulation of the riders’ choice of Time Headway.

Ergonomics indicators: A proposal for sustainable process performance measurement in ergonomics

Process performance measurement has become a challenging task for organizations, which have many various processes, in today’s globalized world. This challenging task is also remarkable in ergonomics, and combining sustainability with ergonomics can provide beneficial solutions for assessing risks and providing ergonomically favourable conditions for human well-being. In this paper, new ergonomics indicators are proposed, classified, and described in detail to overcome this challenge through a systematic literature review that integrates ergonomics and sustainability. By considering sustainability indicators selected from the review, the proposed ergonomics indicators are presented within a three-dimensional structure. This structure enables measuring the performance on various issues in an organization such as occupational health and safety, decent work, technology, working conditions, employee empowerment and development, charities, innovations, and recycling. Through systematic measurements using these indicators, more traceable and manageable processes can be achieved. Hence, ergonomists or managers can identify and prevent risky conditions practically. Practitioner Summary: This paper proposes ergonomics indicators and detailed descriptions for ensuring sustainable process performance measurement in ergonomics. The sustainability indicators presented as references for these proposals are utilized through selection and consolidation from literature. The ergonomics indicators are structured within a sustainability framework that considers six sustainability sub-dimensions proposed for ergonomics.

Safe Local Aerial Manipulation for the Installation of Devices on Power Lines: AERIAL-CORE First Year Results and Designs

The power grid is an essential infrastructure in any country, comprising thousands of kilometers of power lines that require periodic inspection and maintenance, carried out nowadays by human operators in risky conditions. To increase safety and reduce time and cost with respect to conventional solutions involving manned helicopters and heavy vehicles, the AERIAL-CORE project proposes the development of aerial robots capable of performing aerial manipulation operations to assist human operators in power lines inspection and maintenance, allowing the installation of devices, such as bird flight diverters or electrical spacers, and the fast delivery and retrieval of tools. This manuscript describes the goals and functionalities to be developed for safe local aerial manipulation, presenting the preliminary designs and experimental results obtained in the first year of the project.

Two-Sided Matching on Comprehensive Transportation Network Emergency Vehicles’ Allocation

In emergency rescue, the allocation of comprehensive transportation network emergency vehicles often affects the efficiency of the whole rescue process. In the context of disasters, this paper researches the one-to-many two-sided matching problem between the emergency vehicles and the materials to be transported. Firstly, based on the needs of both parties involved in the matching, the satisfaction evaluation systems are constructed; with the goal of maximizing the weighted satisfaction of the affected areas and vehicles, the optimization model of the materials and emergency vehicles matching is established; then, an improved National Intern Matching Program (NIMP) algorithm is designed to solve the model, which is based on the k: 1 experimental pairing and updating ideas, and can take into account the capacity and destination constraints of vehicles in the matching process. Finally, through the calculation of an example, the matching scheme can make the satisfaction of material transportation reach 0.7392, and the simulation analysis proves that the scheme keeps certain stability in risky conditions.

A novel hesitant-fuzzy-based group decision approach for outsourcing risk

Outsourcing is recognized as a strategic instrument for companies to move towards diversified operation advantages and efficient global market. However, outsourcing agreements may fail due to insufficient risk consideration and evaluation. This requires an effective risk evaluation approach that necessitates an entire comprehension of the system, its requirements and dimensions. This paper proposes a novel fuzzy group multiple-criteria decision-making approach through integrating triangular fuzzy hesitant sets (TFHS), Failure Mode and Effect Analysis (FMEA) and combined compromise solution (CoCoSo) algorithm. This approach (F-FMEA-CoCoSo, henceforth) analyzes and evaluates the possible risks level of alternative outsourcing providers. It hereby provides measurable information for managers according to the linguistic opinions of industrial experts. Utilization of hesitant fuzzy variables allows decision making participants to state their opinion more precisely. A case study of an Iranian chemical company is used to exemplify the applicability and suitability of the proposed F-FMEA-CoCoSo approach. The model reflects an analytical approach while experts are experiencing considerable uncertainty in risky conditions of outsourcing operations. CoCoSo contains an integrated approach of compromise solutions and its utilization enables investigators to assure results reliability which is proven via the sensitivity analysis. Through this study, we found that risk evaluation of outsourcing providers must consider four key-factors: multi-experts, multi-criteria, multi-uncertainties and measurability.

Exploring transition durations of rear-end collisions based on vehicle trajectory data: A survival modeling approach

The time-to-collision (TTC) index and its extended variants have been widely utilized to assess rear-end collision risks, but the characteristics of the time-series data have not been fully explored, especially for the transition from safe to risky conditions. This study proposes a novel approach in rear-end collision risk analysis based on the concept of transition durations. The vehicle trajectory data were extracted and the TTC index was used to identify risky and safe conditions. Three important transition durations are defined and their rationalities for evaluating rear-end collision risks are examined by developing random-parameters accelerated failure time (AFT) survival models. Furthermore, a typical case from real trajectory data is taken to discuss the limitations of using TTC and its variants, and the advantage of the proposed transition durations. The results of random-parameters AFT models reveal contributing factors affecting the length of three durations and demonstrate the rationality of transition durations in rear-end collision risks analysis. It is indicated that the proposed method outperforms TTC and its variants in evaluating rear-end collision risks, because it could not only provide the information of time point but also the variation of time-series data.

EMPLOYABILITY OF AN BIOMETRIC SYSTEMS FOR ENHANCING THE ‘SECURITY SYSTEMS FOR VEHICLES’

These days, the pace of vehicle theft is exceptionally high worldwide, and the circumstances are far and away more terrible in agricultural nations. Hence, securing vehicles with a smart, dependable, viable and monetary framework is vital. The current improvements for vehicle security have a few constraints, including a high false following rate, simple deactivation and significant expense. In this examination, a finger impression vehicle security framework has been designed and carried out using a sensor-network framework that utilizes Global Positioning System (GPS) and a Global framework for versatile Communication to set the warning in risky conditions. This state-of-the-art innovation is equipped for securing, screen and setting cautions in less time.

Tree species mixing can increase stand productivity, density and growth efficiency and attenuate the trade-off between density and growth throughout the whole rotation.

Background and AimsMany recent studies emphasize that mixed species is a promising silvicultural option for sustainable ecosystem management under uncertain and risky future environmental conditions. However, compared with monocultures, knowledge of mixed stands is still rather fragmentary. This comprehensive study analysed the most common Central European tree species combinations to determine the extent to which mono-layered species mixing (1) can increase stand productivity and stem diameter growth, (2) increase stand density or growth efficiency, and (3) reduce competition and attenuate the relationship between stand density and stem diameter growth compared with mono-specific stands.MethodsThe study was based on 63 long-term experimental plots in Germany with repeated spatially explicit stand inventories. They covered mono-specific and mixed species stands of Norway spruce (Picea abies), silver fir (Abies alba), Scots pine (Pinus sylvestris), European beech (Fagus sylvatica), sessile oak (Quercus petraea), European ash (Fraxinus excelsior) and sycamore maple (Acer pseudoplatanus). Based on spatially explicit measurement, we quantified for each tree the intra- or inter-specific neighbourhood, local stand density and growth. We applied mixed models to analyse how inter-specific neighbourhoods modify stand productivity, stand density, growth efficiency, individual tree growth and the trade-off between individual tree growth and stand productivity.Key ResultsWe found stand productivity gains of 7–53 % of mixed versus mono-specific stands continuing over the entire rotation. All mixtures achieved a 3–36 % higher leaf area index until advanced stand age. Stem diameter growth increased by up to 31 % in mixed stands. The growth efficiency of the leaf area was up to 31 % higher, except in mixtures of sessile oak and European beech. The trade-off between stem diameter growth and stand productivity was attenuated by the mixture.ConclusionsThe increased productivity was mainly based on a density increase in the case of Norway spruce/silver fir/European beech and sessile oak/European beech and it was based on a more efficient resource use given the same stand density in the case of Scots pine/European beech and European ash/sycamore maple. In the other species assemblages the increased productivity was based on a combination of density and efficiency increase. We hypothesize that the density effect may be site-invariant and mainly depends on the structural species complementarity. The efficiency increase of growth may depend on the growth-limiting factor that is remedied by mixture and thus be co-determined by the site conditions. For forest management, the results indicate increased stand and tree size growth by species mixing. For the common mixtures examined in this study the results show that thinning for the acceleration of stem growth requires less density reduction and causes less stand growth losses than in monocultures. We discuss the consequences of our findings for silvicultural prescriptions for mixed-species stands.

Mild Mitochondrial Uncoupling Decreases Experimental Atherosclerosis, A Proof of Concept.

Aim: Atherosclerosis is responsible for high morbidity and mortality rates around the world. Local arterial oxidative stress is involved in all phases of atherosclerosis development. Mitochondria is a relevant source of the oxidants, particularly under certain risky conditions, such as hypercholesterolemia. The aim of this study was to test whether lowering the production of mitochondrial oxidants by induction of a mild uncoupling can reduce atherosclerosis in hypercholesterolemic LDL receptor knockout mice. Methods: The mice were chronically treated with very low doses of DNP (2,4-dinitrophenol) and metabolic, inflammatory and redox state markers and atherosclerotic lesion sizes were determined. Results: The DNP treatment did not change the classical atherosclerotic risk markers, such as plasma lipids, glucose homeostasis, and fat mass, as well as systemic inflammatory markers. However, the DNP treatment diminished the production of mitochondrial oxidants, systemic and tissue oxidative damage markers, peritoneal macrophages and aortic rings oxidants generation. Most importantly, development of spontaneous and diet-induced atherosclerosis (lipid and macrophage content) were significantly decreased in the DNP-treated mice. In vitro, DNP treated peritoneal macrophages showed decreased H2O2 production, increased anti-inflammatory cytokines gene expression and secretion, increased phagocytic activity, and decreased LDL-cholesterol uptake. Conclusions: These findings are a proof of concept that activation of mild mitochondrial uncoupling is sufficient to delay the development of atherosclerosis under the conditions of hypercholesterolemia and oxidative stress. These results promote future approaches targeting mitochondria for the prevention or treatment of atherosclerosis.

Investigation on Hydrate Growth at the Oil-Water Interface: In the Presence of Wax and Surfactant.

Natural gas hydrates can readily form in deep-water-oil production processes and pose a great threat to subsea pipeline flow assurance. The usage of surfactants and hydrate antiagglomerants is a common strategy to prevent hydrate hazards. In water/wax-containing oil systems, hydrate coexisting with wax could lead to more complex and risky transportation conditions. Moreover, the effectiveness of surfactants and hydrate antiagglomerants in the presence of wax should be further evaluated. In this work, for the purpose of investigating how wax and surfactants could affect hydrate growth at the oil-water interface, a series of microexperiments was conducted in an atmospheric visual cell where the nucleation and growth of hydrates took place on a water droplet surrounded by wax-containing oils. On the basis of the experimental phenomena observed using a microscope, the formation of a hydrate shell by lateral growth, the collapse of a water droplet after hydrate initial formation, and the formation of hollow-conical hydrate crystals were identified. These experimental phenomena were closely related to the concentration of wax and surfactant used in each case. In addition, it was shown that the effectiveness of the surfactant could be weakened by wax molecules. Moreover, there existed a critical wax content above which the effectiveness of the surfactant was greatly reduced and the critical wax content gradually increased with increasing surfactant concentration. This work could provide guidance for hydrate management in wax-containing systems.

IMPORTANCE OF FAILURE MODES AND EFFECT ANALYSIS APPLICATION FOR RISK ANALYSIS IN BARAPUKURIA COAL MINE, BANGLADESH

Because of the complex working situations, mining is known for being one of the most hazardous industries in the world. The working activities in such risky conditions in the underground coal mine often leads to many types of accidents. The working condition of Barapukuria Coal Mine (BCM) which is a producing underground coal mine in the North-western part of Bangladesh, has become insecure due to the lack of practising appropriate plan and methodology for reducing risk.Therefore, this study aims to assess the potential hazards by failure modes and effect analysis (FMEA) method in BCM. FMEA is a quality management tool often used to identify possible failure mode by calculating a risk priority number (RPN) from severity, occurrence, and detection scores. A noteworthy aspect in FMEA is the estimation of RPN to prioritize failure modes. In this phase, a quality point scale (1-10) is typically used to measure the three facets of a failure mode's risks, and it indicates that the higher the score, the greater the chance of accidents. We have studied some accidents data in BCM it indicates that roof fall is more hazardous compared to other accidents. With the help of FMEA method, we have assessed causes and effects of accidents and finally recommended actions to reduce hazards. Therefore, an integrated approach is a burning necessity that can predict the risk before the actual mishaps and the FMEA can be a handy solution in this case as it is a robust tool for identifying multi-horizon risks and mitigating threats that can be strengthened further.

Information provision and congestion pricing in a risky two-route network with heterogeneous travelers

Travel information and congestion pricing are two major approaches to relieving congestions. This paper examines travelers’ travel strategies and route choices in a road network with a risky route and a safe route, where travel information pricing are jointly implemented. We derive the equilibrium of the risk-averse travelers with heterogeneous Values of Time (VOTs) under various information regimes. We find that information regarding the risky road conditions would not necessarily improve the expected system travel time. When there is no toll, free information surprisingly makes congestion worse. When information is not free, congestion may be reduced if both toll and information are properly priced. We also examine the distributional effects of information provision across travelers with different VOTs. Travelers with low VOTs who do not use information are not affected by the price of information. Travelers with intermediate VOTs always benefit from information provision regardless of its price. Finally, travelers with high VOTs are better off when the information price exceeds a threshold.

Biomechanics analysis in coffee harvesting activity in Colombia

During this case study, the risks of posture, strength and repetition associated with the activity of manual coffee harvesting were evaluated. The sample studied was 26 volunteers who participated in the completion of a Nordic questionnaire, 10 of these were evaluated using observational,and postural tools and 8 people participated in the biomechanical evaluation of postural and muscular load using electromyography and inertial. Seven muscles and two body segments of the upper limbs were evaluated. The goal was to assessthe working conditions of coffee manual harvesting considering ergonomics.The results of the discomfortsweremanifested in the Nordic questionnaire where it was evident that throughout a workday harvesting coffee, the discomfort focuses on the back, lower back, hands,and feet. In the muscle load evaluation was identified that the muscles with the highest activity were the Extensor, Flexor Carpi Ulnar and the trapezius.On average,their muscular activity was20% of their maximum volunteer contraction when performing the statistical analysis. -Tics showed a greater correlation in muscle activationbetween the Carpi Radial Extender and the trapezius. In the postural evaluation of the body segments from the coffee harvesters evaluated, it was identified that they only maintain between 10% and 20% in neutral ranges, so they are always in risky conditions. In conclusion, it is necessary to carry out interventions in the Colombian coffee sector not only because of these evaluated conditions but also for theconditions in theirwork environment.

Are there sex differences in physiological parameters and reaction time responses to overload in firefighters?

Male and female firefighters work side-by-side in the same in strenuous and risky conditions. Anthropometrics, physiological, and reaction time (mean of reaction time -MRT-, and errors made -E) parameters of 12 Female and 13 Male firefighters were compared. Effect of overload (step test with and without equipment) on the MRT and E were analyzed on 3 trials (T1 = 1-1s, T2 = 0.5-1s, T3 = 0.5-0.5s), compared with a pre-test condition (basal). T-test between males and females was applied to assess differences (p<0.05) in all parameters. ANOVA with repeated measures and Bonferroni on 3 conditions of step test between males and females was applied in reaction time variables. Between MRT and E, in T1, T2 and T3 trials and the 3 test conditions, ANCOVA models with interactions were used. Differences (p<0.05) in anthropometric, physiological and reaction time data emerged across groups, and on the 3rd trials (T3 vs T1 and T2) in reaction time parameters of each group. ANCOVA showed differences (p<0.001) in E among trials. Post hoc showed significant differences in T1vsT3 and T1vsT2. MRT x trial interaction was extremely significant (P<0.001). Implementing fitness and reaction time exercise programs is important to decrease the injury risk and increase work capacity in firefighters with reference to female workers.

Effect of Fillial Value and Commitment To Family Ability in Early Detection of High Risk Pregnancy

Pregnancy and childbirth are physiological processes that women experience, but sometimes have risky conditions. This study aims to determine the effect of filial value and commitment to family ability in early detection of high risk pregnancy. This study used a cross sectional design. The sample size of 112 from a population of 155 by simple random sampling. Data analysis using SEM PLS. The results (52.7%) were in early adulthood , (62.5%) secondary education, (75%) worked in private (57.1%) had good self-esteem, (52, 7%) self -motivated enough, (50%) good previous behavior. SEM-PLS statistical analysis CFA, fillial value were 10.23 and commitment was 13.78, on family abilities. The value of the fillial value (0.201), the value of commitment (0.102). R2 value (0.63) and Q2 value of 0.65. In further research, it is necessary to involve other factors to increase family capacity, especially in the ability of families to detect high-risk pregnancies early.

Evaluation of the Relationship between Cesarean Section and Childhood Allergic Disorders

Aim: The aim of this study is to investigate and examine the possibility that cesarean section, which is becoming increasingly common today, may cause risky conditions such as allergies not only for the mother but also for the baby in the future. Material and Method: The questionnaire was applied to the mothers who applied to the Family Medicine outpatient clinic between July and November 2020, who accepted to participate in the study and received written consent. Results: Of the 90 participants included in the study, 45 (50%) had cesarean section and 45 (50%) had a normal birth. No variation was found according to the type of delivery in those whose children were diagnosed with allergies. Likewise, there was no statistical relationship between the presence of allergies and the variables we looked at. Among the other variables examined, there was only a significant difference in smoking during pregnancy according to the mode of delivery (p = 0.041). Conclusion: Although it is prohibited off-label cesarean delivery, which can be left to the patient due to commercial concerns, is a delivery method to be chosen by a doctor only in the presence of an indication. Cesarean section may have complications for the mother and the baby, and the recommended method is to deliver the baby with normal delivery through the vaginal canal. Pregnant women should be informed that normal birth is the healthiest delivery method with correct information.

The Standard Model of Rational Risky Decision-Making

Expected utility theory (EUT) is currently the standard framework which formally defines rational decision-making under risky conditions. EUT uses a theoretical device called von Neumann–Morgenstern utility function, where concepts of function and random variable are employed in their pre-set-theoretic senses. Any von Neumann–Morgenstern utility function thus derived is claimed to transform a non-degenerate random variable into its certainty equivalent. However, there can be no certainty equivalent for a non-degenerate random variable by the set-theoretic definition of a random variable, whilst the continuity axiom of EUT implies the existence of such a certainty equivalent. This paper also demonstrates that rational behaviour under utility theory is incompatible with scarcity of resources, making behaviour consistent with EUT irrational and justifying persistent external inconsistencies of EUT. A brief description of a new paradigm which can resolve the problems of the standard paradigm is presented. These include resolutions of such anomalies as instant endowment effect, asymmetric valuation of gains and losses, intransitivity of preferences, profit puzzle as well as the St. Petersburg paradox.

Bazı Peyzaj Bitkilerinde Krom Konsantrasyonunun Tür, Organ ve Trafik Yoğunluğuna Bağlı Değişimi

Günümüzde insan ve çevre sağlığını tehdit eden en önemli problemlerin başında hava kirliliği gelmektedir. Hava kirliliğinin pek çok bileşeni bulunmakla birlikte, bunlar arasında ağır metaller ayrı bir öneme sahiptir. Bunun sebebi ağır metallerin bazılarının düşük konsantrasyonlarda bile toksik olmaları, canlılar için besin elementi olan birçok ağır metalin bile yüksek konsantrasyonlarda zararlı olmaları, canlı bünyesinde biyobirikme eğiliminde olmaları, doğada kolay kolay bozulmamaları ve bunlara ek olarak sanayi ve trafik kaynaklı olarak havadaki konsantrasyonlarının sürekli artmasıdır. Bundan dolayı özellikle trafiğin yoğun olduğu, sanayi faaliyetlerinin yürütüldüğü ve nüfusun yoğun olduğu alanlar gibi riskli alanlarda havadaki ağır metal konsantrasyonlarının izlenmesi büyük önem taşımaktadır. Bu çalışmada da, Samsun kent merkezinde yetiştirilen ve peyzaj çalışmalarında sıklıkla kullanılan; Tilia tomentosa, Aesculus hippocastanum, Ligustrum vulgare ve Catalpa bignoides türlerinin, trafiğin yoğun olduğu, az yoğun olduğu ve hemen hemen hiç olmadığı alanlarda yetişen bireylerinde Cr konsatrasyonlarının değişimleri belirlenmeye çalışılmıştır. Çalışma kapsamında bitkilerden yaprak, kabuk ve odun örnekleri toplanmış, kabuk ve yapraklarda ayrıca yıkama işlemi uygulaması da yapılmıştır. Çalışma sonucunda, çalışmaya konu türlerde Cr konsantrasyonlarının tür, organ ve trafik yoğunluğu bazında önemli ölçüde değiştiği belirlenmiştir.

Case study comparing Fiala-based thermophysiological model and PHS Index with experimental data to predict heat strain in normal and protective clothing

The use of protective clothing under extreme conditions leads to heat stress with undesired consequences on human physiology. As a prevention measure, thermal indices and thermophysiological models have been developed. Based on these models and indices, it is possible to estimate the time limits for staying under risky conditions, e.g., by the predicted rectal temperature whose value is one of the most important parameters used for assessing the heat stress. This article is focused on the comparison of rectal and mean skin temperature prediction realized by the Fiala-based thermophysiological model (FMTK) and Predicted heat strain (PHS) index with results from the real experiment for normal and protective clothing. Three types of ensembles were tested and simulated as follows: Klimatex underwear, air-permeable military NBC suit M2000 (FOP), and impermeable chemical protective clothing Tychem-F. The real experiments of thermal strain were performed with one male participant (80 kg, 1.75 m) walking on the treadmill located in the climate chamber. The temperature range for neutral and hot tests was set from 25 °C to 40 °C. The rectal temperature, skin temperatures, and heart rate were measured. The results showed that PHS index is well usable for normal clothing (Klimatex underwear) and air-permeable protective clothing (FOP) under various ambient temperatures, and it is able to give results similar to FMTK model and experiment, the mean absolute error MAE for rectal temperature prediction was for all ambient temperatures lower than 0.5 °C. FMTK model demonstrated good predictability for impermeable protective clothing Tychem-F, the maximum value of MAE 0.69 °C. Whereas PHS index showed several times larger error, the maximum value higher than 1.8 °C, in the prediction for this type of clothing. The performed simulations showed that the accuracy of the prediction by the PHS index is not so strongly dependent on the value of the overall clothing resistance, but it depends on the value of the moisture permeability index (permeable vs impermeable clothing) which is connected with the water vapor partial pressure under the clothing.

The effect of predation risk on group behaviour and information flow during repeated collective decisions

Making fast and accurate group decisions under uncertain and risky conditions is a fundamental problem for groups. Currently, there is little empirical evidence of how natural selection (such as environmental predation risk) has shaped the mechanisms of group decision making. We repeatedly tested individually marked guppies, Poecilia reticulata, from the upper and lower reaches of the Aripo and Turure rivers in a Y-maze and found that populations that had evolved under different predation regimes differed in their decision-making speed. All groups decreased decision time over successive trial rounds, but fish from low-predation environments did so at a greater rate than fish from high-predation environments. This effect was only significant when fish were tested in groups of eight, not when tested individually. Decision-making accuracy was not significantly different between high- and low-predation populations. Group behaviour differed according to predation risk and trial round, most notably with low-predation groups reducing the amount of positional switching over successive trial rounds at a greater rate than high-predation groups. While fish from both predator risk environments had repeatable within-shoal positioning behaviour as they swam down the maze, only fish from the high-predation groups had repeatable finishing positions. Meaningful measures of information transfer (mean pairwise transfer entropy) were only recorded in low-predation groups, and here there was a significant effect of source river on information flow within groups. Aripo groups increased information flow over successive trial rounds, while Turure groups did not. Variation in mean pairwise transfer entropy increased over successive trial rounds for both low-predation populations, suggesting that information used to make movement decisions became less homogeneously distributed and increasingly directed through a subset of individuals. Predation pressure is a ubiquitous selection force, and these findings may apply to a variety of natural social groups.