50,241 research outputs found
The effects of driver training on simulated driving performance
No full textGiven that the beneficial effects of driver training on accident risk may not be an appropriate criterion measure, this study investigates whether professionally trained and experienced drivers exhibit safer driving behaviour in a simulated driving task compared with drivers without professional driver training. A sample of 54 police trained drivers and a sample of 56 non-police trained drivers were required to complete two tasks. Firstly to overtake a slow-moving bus on a hazardous stretch of single-lane road with bends and hills and secondly to follow a lead vehicle travelling at 55 mph in a built-up section with a speed limit of 30 mph. Results showed that in comparison with non-police trained drivers, police drivers were significantly less likely to cross the central division of the road at unsafe locations during the overtaking task and reduced their speed on approach to pedestrians at the roadside in the following task to a greater extent. Police drivers also adopted a more central lane position compared with non-police trained drivers on urban roads and at traffic lights during the following task. Driver group differences in simulated driving performance are discussed with reference to the implications for driver training assessment and skill development
An investigation on the effect of driver style and driving events on energy demand of a PHEV
No full textEnvironmental concerns, security of fuel supply and CO2 regulations are driving innovation in the automotive industry towards electric and hybrid electric vehicles. The fuel economy and emission performance of hybrid electric vehicles (HEVs) strongly depends on the energy management system (EMS). Prior knowledge of driving information could be used to enhance the performance of a HEV. However, how the necessary information can be obtained to use in EMS optimisation still remains a challenge. In this paper the effect of driver style and driving events like city and highway driving on plug in hybrid electric vehicle (PHEV) energy demand is studied.
Using real world driving data from three drivers of very different driver style, a simulation has been exercised for a given route having city and highway driving. Driver style and driving events both affect vehicle energy demand. In both driving events considered, vehicle energy demand is different due to driver styles. The major part of city driving is reactive driving influenced by external factors and driver leading to variation in vehicle speed and hence energy demand. In free highway driving, the driver choice of cruise speed is the only factor affecting vehicle energy demand
Driver attitude and attribution : implications for accident prevention
No full textThis study involved self-completion questionnaire-based surveys in which a total of almost
1800 respondents took part. Attributional bias identified by previous research in relation to
drivers' causal attributions for road accidents (Preston & Harris, 1965; Clay, 1987) was
more fully explored with the aid of both objectively and subjectively culpable driver samples.
Banks et al (1977) demonstrated the utility of distinguishing drivers according to culpability
in relation to accident fatalaties. The current study examined the utility of distinguishing
subjectively culpable, non-culpable, and non-accident driver groups in relation to road
accidents with a variety of consequences, in relation to factors which may predispose drivers
to accident involvement. This study involved a large sample of drivers who were
representative of the general population of licenced drivers in Britain, and specifically
focussed samples which allowed the influence of objective and subjective culpability to be
ascertained, while a relatively small cross-cultural survey allowed a focus on young drivers
(up to 25 years), involving Victorian (Australian) licenced drivers and a sub-sample of young
British drivers drawn from the main British sample.
The main objectives of the current study were to evaluate drivers' awareness of their potential
for active accident avoidance, exploring attribution issues raised by previous research and
examining factors which may contribute to road accidents in relation to self-reported accident
involvement and culpability and their implications for accident prevention.
The main findings were that drivers seemed to have a tendency to attribute more
responsibility to "other drivers" than to themselves for accidents in which they had been
involved, and to consider that such other drivers had more scope for accident avoidance than
they did themselves. Such tendencies, although very considerably reduced, were not
eradicated within the driver group deemed culpable by traffic police investigative teams.
These findings were broadly consistent with those of Clay (1987) and Preston & Harris
(1965), suggesting a lack of awareness of personal influence on accident occurrence, at least
to some degree, with implications for accident prevention, the quality of social interaction in
the driving environment (Knapper & Cropley, 1980), and the driver's potential to learn from
experience.
Perhaps more importantly, the other major finding was that clear distinctions could
nonetheless be made between drivers in accordance with self-reported accident involvement
and culpability in relation to driver affect/state, self-perception, attributions for accident
causation, and attitudinal/behavioural tendencies, in a manner which seemed to be meaningful
in terms of driver susceptibility to accident risk. Ile pattern of response for accident
involvement and culpability effects was then examined in relation to the norms which
emerged for age and sex, while the effects of driving experience duration and intensity were
examined separately. The second point of focus on any distinctive features of younger driver
risk, also allowed assessment of generalizability of findings across cultures, to some degree.
The findings appear to have considerable implications for the development of effective
accident prevention strategies, while suggesting that further exploration of drivers' causal
attribution bias in relation to road accidents and distinctions between drivers according to
subjective culpability may offer considerable safety benefits
The effectiveness of police driver training on attitudes, beliefs and skills
No full textThe research undertook an analysis of the effectiveness of police driver training in the
development of appropriate driver attitudes and skills in terms of the objectives of the
training. The research focused upon the Standard/Response course of the Essex
Police. Trainees attitudes and skill, levels were measured at the beginning and after
each phase of training. An assessment of the stability and longevity of attitudes and
skill levels was made 3-10 months after the training. In addition, the influence of
police driving instructors and police recruitment policy on the development of
attitudes was made. From the research, an evaluation has also been made of the
effectiveness of different methods of researching and measuring an individual's
attitude towards a particular behaviour, having used direct, semi-direct, and indirect
methods of attitude measurement
Fuzzy Evolutionary Approaches for Bus and Rail Driver Scheduling
No full textBus and train driver scheduling is a process of partitioning blocks of work, each of which is serviced by one vehicle, into a set of legal driver shifts. The main objectives are to minimise the total number of shifts and the total shift cost. Restrictions imposed by logistic, legal and union agreements make the problem more complicated.
The generate-and-select approach is widely used. A large set of feasible shifts is generated first, and then a subset is selected, from the large set, to form a final schedule by the mathematical programming method. In the subset selection phase, computational difficulties exist because of the NP-hard nature of this combinatorial optimisation problem. This thesis presents two evolutionary algorithms, namely a Genetic Algorithm and a Simulated Evolution algorithm, attempting to model and solve the driver scheduling problem in new ways.
At the heart of both algorithms is a function for evaluating potential driver shifts under fuzzified criteria. A Genetic Algorithm is first employed to calibrate the weight distribution among fuzzy membership functions. A Simulated Evolution algorithm then mimics generations of evolution on the single schedule produced by the Genetic Algorithm. In each generation an unfit portion of the working schedule is removed. The broken schedule is then reconstructed by means of a greedy algorithm, using the weight distribution derived by the Genetic Algorithm. The basic Simulated Evolution algorithm is a greedy search strategy that achieves improvement through iterative perturbation and reconstruction. This approach has achieved success in solving driver scheduling problems from different companies, with comparable results to the previously best known solutions.
Finally, the Simulated Evolution algorithm for driver scheduling has been generalized for the set covering problem, without using any special domain knowledge. This shows that this research is valuable to many applications that can be formulated as set covering models. Furthermore, Taguchi's orthogonal experimental design method has been used for the parameter settings. Computational results have shown that for large-scale problems, in general the proposed approach can produce superior solutions much faster than some existing approaches. This approach is particularly suitable for situations where quick and high-quality solutions are desirable
A Sinusoidal Current Driver With an Extended Frequency Range and Multifrequency Operation for Bioimpedance Applications
No full textThis paper describes an alternative sinusoidal current driver suitable for bioimpedance applications where high frequency operation is required. The circuit is based on a transconductor and provides current outputs with low phase error for frequencies around its pole frequency. This extends the upper frequency operational limit of the current driver. Multifrequency currents can be generated where each individual frequency is phase corrected. Analysis of the circuit is presented together with simulation and experimental results which demonstrate the proof of concept for both single and dual frequency current drivers. Measurements on a discrete test version of the circuit demonstrate a phase reduction from 25 ^{\circ} to 4 ^{\circ} at 3 MHz for 2 mAp-p output current. The output impedance of the current driver is essentially constant at about 1.1 M \Omega over a frequency range of 100 kHz to 5 MHz due to the introduction of the phase compensation. The compensation provides a bandwidth increase of a factor of about six for a residual phase delay of 4 ^{\circ
Development and validation of a self-report measure of bus driver behaviour
No full textThere are likely to be individual differences in bus driver behaviour when
adhering to strict schedules under time pressure. A reliable and valid
assessment of these individual differences would be useful for bus companies
keen to mitigate risk of crash involvement. This paper reports on three studies
to develop and validate a self-report measure of bus driver behaviour. For study
1, two principal components analyses of a pilot questionnaire revealed six
components describing bus driver behaviour and four bus driver coping
components. In study 2, test-retest reliability of the components were tested in
a sub-sample and found to be adequate. Further, the 10 components were used to
predict bus crash involvement at three levels of culpability with consistently
significant associations found for two components. For study 3, avoidance coping
was consistently associated with celeration variables in a bus simulator,
especially for a time-pressured drive. Statement of Relevance:The instrument can
be used by bus companies for driver stress and fatigue management training to
identify at-risk bus driver behaviour. Training to reduce the tendency to engage
in avoidance coping strategies, improve evaluative coping strategies and hazard
monitoring when under stress may improve bus driver safety
Driver reactions on ecological feedback via different HMI modalities
No full textNowadays there already exists a large amount of driving-related information displayed in the dashboard and thus additional information concerning ecological driving might enlarge the workload of the driver further. This raises the question whether the presentation of additional ecologic information via the haptic channel is more efficient and comfortable for the driver compared to a visual presentation. Previous studies proved the impact of driver feedback systems on the reduction of fuel consumption. However, most of the studies only dealt with visual displays. Thus in the present study a visual, a haptic, and a visual-haptic interface were designed for an acceleration and a gear shift advice system. Subsequently their impact on the acceleration and the gear shift behavior of the driver as well as their subjective acceptance were compared. Results showed that especially the combination of the visual and haptic modality led to the fastest reaction times and smallest deviations from the optimal acceleration and gear shift behavior. However, concerning the acceptance participants preferred the visual display
Most Small Cerebral Cortical Veins Demonstrate Significant Flow Pulsatility: A Human Phase Contrast MRI Study at 7T
No full textPhase contrast MRI (pcMRI) has been used to investigate flow pulsatility in cerebral arteries, larger cerebral veins, and the cerebrospinal fluid (CSF). Such measurements of intracranial pulsatility and compliance are beginning to inform understanding of the pathophysiology of conditions including normal pressure hydrocephalus, multiple sclerosis, and dementias. We demonstrate the presence of flow pulsatility in small cerebral cortical veins, for the first time using pcMRI at 7 T, with the aim of improving our understanding of the hemodynamics of this little-studied vascular compartment. A method for establishing where venous flow is pulsatile is introduced, revealing significant pulsatility in 116 out of 146 veins, across eight healthy participants, assessed in parietal and frontal regions. Distributions of pulsatility index (PI) and pulse waveform delay were characterized, indicating a small, but statistically significant (p < 0.05), delay of 59 ± 41 ms in cortical veins with respect to the superior sagittal sinus, but no differences between veins draining different arterial supply territories. Measurements of pulsatility in smaller cortical veins, a hitherto unstudied compartment closer to the capillary bed, could lead to a better understanding of intracranial compliance and cerebrovascular (patho)physiology
Smart driving aids and their effects on driving performance and driver distraction
No full textIn-vehicle information systems have been shown to increase driver workload and cause distraction; both of which are causal factors for accidents. This simulator study evaluates the impact that two designs for a smart driving aid, and scenario complexity have on workload, distraction and driving performance. Results showed that real-time delivery of smart driving information did not increase driver workload or adversely effect driver distraction, while having the effect of decreasing mean driving speed in both the simple and complex driving scenarios. Subjective workload was shown to increase with task difficulty, as well as revealing important differences between the two interface designs
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