When attempting to perform bi-phasic steering movements (such as a lane change) in the absence of visual and inertial feedback, drivers produce a systematic heading error in the direction of the lane ...change (Wallis et al., Curr Biol 12(4):295-299, 2002; J Exp Psychol Hum Percept Perform 33(55):1127-1144, 2007). Theories of steering control which employ exclusively open-loop control mechanisms cannot accommodate this finding. In this article we show that a similar steering error occurs with obstacle avoidance, and offer compelling evidence that it stems from a seemingly general failure of human operators to correctly internalise the dynamics of the steering wheel. With respect to lateral position, the steering wheel is an acceleration control device, but we present data indicating that drivers treat it as a rate control device. Previous findings from Wallis et al. can be explained the same way. Since an open-loop control mechanism will never succeed when the dynamics of the controller are internalised improperly, we go on to conclude that regular, appropriately timed sensory feedback--predominantly from vision--is necessary for regulating heading, even during well-practiced, everyday manoeuvres such as lane changing and obstacle avoidance.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, ODKLJ, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Previous behavioural research (Land and Horwood in Nature 377:339-340, 1995) indicates that surprisingly little visual information is required to effect smooth and accurate steering through a curving ...roadway. Based on results from a driving simulator study, Land and Horwood reported that viewing the roadway through two horizontal apertures, one degree of visual angle in height, can result in steering performance which is indistinguishable from that obtained with the whole scene visible. The position of the apertures in the visual field, they claimed, is crucial; higher up leads to less accurate but more stable steering responses, whilst lower down leads to jerky steering but more accurate lane-keeping. These findings are consistent with a two-stage model of steering control proposed by Donges in Human Factors 20:691-707 (1978). However, in a driving simulator, the temporal lag between the input signal received from a control device and the output presented on the display can have profound effects on steering behaviour. In two experiments, we show that the effect of aperture position on steering accuracy and stability is pronounced when a slow frame update rate is used (7.2 Hz, as used by Land and Horwood in Nature 377:339-340, 1995), but largely attenuated with a faster update rate (72 Hz). These results are consistent with the broader empirical literature dealing with temporal delays in manual tracking, and urge a critical reappraisal of the behavioural evidence for the two-stage steering model.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, ODKLJ, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
•SPAD costs in Australasia are minimally documented and opaquely presented.•Little is known about estimated distribution of preventative and reactive SPAD costs.•A multi-case study was undertaken of ...costs incurred by 8 rail operators across Australasia.•The ratio of preventative to reactive costs in low-risk SPAD mitigation was widely varied.•Differences in organisational culture and financial obligations may shape mitigatory spending.
This study sought direct estimates of incidence, preventative costs, and reactive costs associated with the occurrence of low risk (‘typical’) Signal Passed at Danger (SPAD) events in Australasian rail. In a cross-sectional multiple-case design, a descriptive questionnaire was sent to eight operators, and completed by managerial personnel with responsibility for SPAD-risk mitigation. Items addressed SPAD frequency, operator delays, and a range of preventative and reactive costs associated with low-severity (‘low-risk’) SPADs. Delay costs varied between cases, with each having different organisational size and network density. Preventative costs were mostly comprised of internal SPAD prevention team maintenance, participation in a collaborative SPAD Group, and resultant network modifications. Reactive costs were largely comprised of driver-related factors and in two cases, of higher low-risk investigation and regulatory costs. The ratio of preventative to reactive costs (P:R) varied widely, approaching equilibrium for two cases only—both participated in internal and external SPAD preventative team consultation. One freight organisation noted a large P:R imbalance due to very low preventative costs. Low-risk SPADs represent a host of substantial annual costs for each Australasian passenger- and freight-rail organisation. As this study gives preliminary estimates, these likely underestimate the full costs, as multiple other factors are yet to be accounted for. This study justifies the need for detailed analysis of SPAD-associated costs to contrast data from multiple rail organisations, and a clearer picture of how organisational expenses are allocated within SPAD prevention and reaction.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
It has been suggested that certain facial expressions are subject to enhanced processing to maximize the speed and accuracy with which humans locate individuals posing an imminant threat. Evidence ...supporting this proposal comes largely from visual search tasks which have demonstrated that threatening expressions are more rapidly detected than nonthreatening ones. An open criticism of this effect is that it may be due to low-level visual artifacts, rather than biological preparedness. One successful approach for controlling low-level, image-based differences has been to use schematic faces (simplified line drawings). We report experiments aimed at discovering whether the enhanced processing of threatening schematic faces, might also be due to low-level features. The first study replicated the standard threat search advantage, but also measured an effect using similar stimuli comprised of obliquely oriented lines. The effect was also present with these stimuli rotated, a manipulation which served to remove any residual resemblance the abstract images had to a face. The results suggest that low-level features underlie the search advantage for angry, schematic faces, thereby undermining a key source of evidence of a search advantage for specific facial expressions.
► We compare driver behaviour towards two novel warning devices at level crossings with two conventional warning devices. ► We use driving simulation experiment to collect driver responses data. ► We ...develop a binary choice model for predicting the probability of a driver stopping or driving through a crossing. ► We develop mixed regression models for predicting the driver reaction positions.
Improving safety at railway level crossings is costly and as funds are often limited, it is important to search for cost-effective, evidence-based solutions. The effect that the many existing alternative systems have on driver behaviour is not always known. This paper compares driver behaviour towards two novel warning devices (rumble strips and in-vehicle audio warning) at railway level crossings with two conventional warning devices (flashing light and stop sign). Regression models were developed to reflect driver's responses towards the four different types of devices based on data collected from a driving simulation experiment. The regression models include a binary choice model for predicting the probability of a driver stopping or driving through a railway crossing, as well as mixed regression models for predicting the moment at which a driver will produce specific behavioural responses before stopping at a crossing (e.g. initiation of accelerator release and application of foot-pedal brake). Violation results indicated the active systems produced much higher levels of driver compliance than passive devices. Contributing factors, such as age, gender, speed and types of warning devices were found significant at different approach stages to the level crossings. With the application of such behavioural models and traffic conflict techniques in microscopic simulation tools, traffic safety indicators, such as collision likelihood and time-to-collision can be estimated. From these, relative safety comparisons for the different traffic devices are derived.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
A common theme running through much of the visual recognition literature is that faces are special. Many studies now describe evidence for the idea that faces are processed in a dedicated center in ...cortex. Studies have also argued for the presence of evolutionarily expedient pathways dedicated to the processing of certain facial expressions. Evidence for this proposal comes largely from visual search tasks which have established that threatening expressions are more rapidly detected than other expressions: the 'face-in-the-crowd effect'. One open criticism of this effect is that it may be due to low-level visual artifacts, rather than biological preparedness. One attempt at controlling low-level differences has been to use schematic line-drawing versions of faces. This study aimed to discover if there might be alternative issues with schematic stimuli. The first study replicated the face-in-the-crowd threat advantage for schematic faces, but also measured a comparable effect using stimuli comprised of obliquely oriented lines. Similar results were achieved with these stimuli rotated, which had the effect of removing any residual resemblance to a face. The results suggest that low-level features probably underlie the face-in-the-crowd effect described for schematic face images, thereby undermining evidence for a search advantage for specific facial expressions.
Objective:
In this simulator-based study, we aimed to quantify performance differences between joystick steering systems using first-order and second-order control, which are used in underground coal ...mining shuttle cars. In addition, we conducted an exploratory analysis of how users of the more difficult, second-order system changed their behavior over time.
Background:
Evidence from the visuomotor control literature suggests that higher-order control devices are not intuitive, which could pose a significant risk to underground mine personnel, equipment, and infrastructure.
Method:
Thirty-six naive participants were randomly assigned to first- and second-order conditions and completed three experimental trials comprising sequences of 90° turns in a virtual underground mine environment, with velocity held constant at 9 km/h−1. Performance measures were lateral deviation, steering angle variability, high-frequency steering content, joystick activity, and cumulative time in collision with the virtual mine wall.
Results:
The second-order control group exhibited significantly poorer performance for all outcome measures. In addition, a series of correlation analyses revealed that changes in strategy were evident in the second-order group but not the first-order group.
Conclusion:
Results were consistent with previous literature indicating poorer performance with higher-order control devices and caution against the adoption of the second-order joystick system for underground shuttle cars.
Application:
Low-cost, portable simulation platforms may provide an effective basis for operator training and recruitment.
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NUK, OILJ, SAZU, UKNU, UL, UM, UPUK
Control at railway level crossings, using either road rumble strips or in-vehicle auditory warning devices, has the potential to improve safety. This article evaluates driver behavior of these two ...devices and two conventional crossing devices (flashing lights and a stop sign) using a driving simulator. Rumble strips have been seen to encourage drivers to reduce speed earlier on approach to a level crossing but did not affect stopping compliance. In-vehicle auditory warnings have produced high compliance and, overall, have produced behavior comparable to that seen for conventional flashing lights. However, the detailed design features of such devices require further development before more concrete conclusions can be drawn. Contributing factors of age, gender, speed, and types of warning devices were all found to significantly affect driver behavior at crossings. Overall, the results indicate that drivers behave differently and demonstrate higher signal compliance at actively protected crossings than at passively protected crossings for alternative and conventional warning devices.
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BFBNIB, GIS, IJS, KISLJ, NUK, PNG, UL, UM, UPUK
Research concerning the visuomotor control of steering suggests that some steering systems used in underground shuttle cars are not optimal. This research compared the performance of two groups of ...participants steering with a joystick interface through a simulated underground mine environment. The joystick employed either first-order or second-order control of heading. Results indicated poorer performance with second-order steering dynamics in the early stages of the experiment, which generally did not improve to levels observed in the first-order group. Poorer overall performance suggests that equipment manufacturers should reconsider the use of second-order steering dynamics in their vehicle designs. Alternately, simulation-based training technologies may have the potential to safely accelerate individual attainment of competence in the use of second-order steering systems.
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NUK, OILJ, SAZU, UKNU, UL, UM, UPUK
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