Sleepiness contributes to between 20 and 30% of all heavy vehicle accidents throughout the world each year. Professional drivers are particularly susceptible to the effects of sleepiness, due to chronic or acute sleep deprivation, time-on-task effects, driving at circadian low points, and increased daytime sleepiness resulting from sleep disorders. Population surveys of heavy vehicle drivers indicates that a small proportion of drivers use pharmaceutical means in order to help maintain alertness during long-haul trips. Despite the known benefits of amphetamine-type stimulants on reducing fatigue and sleepiness, epidemiological evidence suggests that a large percentage of fatally injured professional drivers test positive to amphetamines. The primary objective of the current thesis was to determine the underlying causes of these sleep- and drug-related accidents. Experimentally, driving performance can be broken down into specific components that can be examined independently. Measures of behavioural disposition provide an indication of the drivers’ mood, ability to determine a change in performance and sleepiness, and whether the driver can make appropriate decisions regarding their ability to drive safely when sleep-deprived. Simulated driving tasks are commonly used to detect driving-related performance in a controlled and safe environment. The task of driving involves a number of components, including attention and vigilance, processing speed and reaction time, visual processes, and executive functioning, which can be measured using neurocognitive tasks. Smaller, pre-conscious neural processes that are undetected by behavioural tasks may also be affected by sleep deprivation, and in turn, affect driving performance. Electrophysiological (eventrelated potentials; ERPs) and neuroimaging (functional magnetic resonance imaging; fMRI) measures can be used to determine the neural underpinnings of visual and auditory processes after sleep deprivation. The aim of this thesis was to determine the effects of one night of sleep deprivation on these driving-related processes in professional drivers. In Experiment 1, nineteen professional drivers underwent two randomised sessions; one session following a normal night of sleep and one session following 24-hours of sleep deprivation. Behavioural disposition, simulated driving performance, neurocognitive measures related to driving, and visual and auditory ERPs were examined in both sessions. Subjective ratings of sleepiness and sleepiness symptoms increased significantly following sleep deprivation. Simulated driving performance and neurocognitive measures of vigilance and reaction time were impaired after sleep deprivation, whereas tasks examining processing speed and executive functioning were less susceptible to sleep deprivation. Event-related potentials of visual and auditory processing indicated that early visual processes were unaffected by sleep deprivation, whereas the amplitude of later cognitive processing was attenuated after sleep deprivation. Driving also involves the ability of the driver to divide his or her attention between different sensory modalities in the driving environment. Experiment 2 presents a functional neuroimaging experiment examining the effect of sleep deprivation on neural activations that occur in response to a cross-modal divided attention task. There was no significant effect of sleep deprivation on behavioural performance. Following sleep deprivation, increased activation was observed in the temporal gyrus, cerebellum and precuneus, compared to activations observed after normal sleep. As no behavioural changes were observed, the results suggest that additional activation may act as a compensatory mechanism. The restorative effect of d-amphetamine on sleep deprivation related impairment was examined in Experiment 3. This pilot study examined eight professional drivers who were past or current users of amphetamine across four, randomised sessions; after normal sleep with oral placebo, after sleep deprivation with oral placebo, after normal sleep with 0.42mg/kg oral d-amphetamine, and after sleep deprivation and 0.42mg/kg oral d-amphetamine. Measures of behavioural disposition appeared to be more affected by d-amphetamine administration after sleep deprivation compared to simulated driving and neurocognitive performance, however these findings need further clarification in a larger sample. The results of the present thesis highlight the detrimental influence of sleep deprivation on a range of driving-related processes. The experienced, professional drivers in this study were able to recognise signs and symptoms of sleepiness, and acted upon these indicators appropriately. Measures of driving-related performance on both simulated driving, and simple neurocognitive tasks were negatively affected by sleep loss, although there is likely to be a discrepancy between on-road and laboratory behaviour. ERP and neuroimaging findings in the present thesis suggest that these sleep-related behavioural effects are caused by small changes in neural processing and neural recruitment. Sleep deprivation can have large implications for safe driving, and this study highlights the importance of promoting and educating the driving public about the dangers of driving when sleepy.

Thesis (M. S.)--Civil and Environmental Engineering, Georgia Institute of Technology, 2009. / Committee Chair: Hunter, Michael; Committee Member: Meyer, Michael; Committee Member: Rodgers, Michael. Part of the SMARTech Electronic Thesis and Dissertation Collection.

Innovative passenger vehicle technologies are required to make significant contributions to climate change mitigation. A number of challenges exist as barriers to their adoption. One key opportunity is the potential for social influence to have a positive impact on adoption rates. Social influence is how an individual's decisions can be influenced by other people – what their peers and others say and do and how this, in turn, affects the diffusion of new behaviours. The mixed method research detailed in this thesis contributes to an emerging interest in social influence in transport studies addressing a key research gap, the spatial aspects of this influence. Spatial analysis of private Toyota Prius vehicle ownership, was undertaken at the Output Area level for London for the period 2000 to 2011. Exploratory Spatial Data Analysis (ESDA), an important first step in spatial analysis, indicated the presence of spatial autocorrelation and Toyota Prius spatial clusters ('hotspots'). These 'hotspots' enlarged over time which can be indicative of social influence. This informed the need for in-depth quantitative analysis on the role of co-variables through the use of a Zero Inflated Negative Binomial model and the choice of case study areas for qualitative interviews. In the model, 'what your neighbours do' is a key co-variable represented by the average number of Priuses from neighbouring Output Areas (OA). This measure of social influence had a positive impact on the number of Toyota Priuses in a neighbourhood. The likelihood of Prius ownership in an OA increases by over 50% when the average number of Priuses in neighbouring OA increases by one. The case study OAs were examined in detail setting the scene for the qualitative interviews. Nine face-to-face semi-structured interviews were undertaken with current and potential future Toyota Prius owners. All referenced at least one form of social influence. The influences included direct observation of the vehicles, the opportunity to trial vehicles and changes in the symbolism of the vehicle through its adoption by others. Broader findings were consistent with the literature, for example with regard to the role of congestion charge exemptions and the socio-economic background of the participants. The confirmation of social influence indicated by these findings could assist in the geographic positioning of demonstration schemes or in the allocation of grants, with the economic assessment benefits of grant programmes, because of the 'knock-on' effects of social influence, potentially being wider than conventionally assumed.

The Type-II dilemma zone refers to the segment of roadway approaching an intersection where drivers have difficulty deciding to stop or proceed through at the onset of the circular yellow (CY) indication. Signalized intersection safety can be improved when the dilemma zone is correctly identified and steps are taken to reduce the likelihood that vehicles are caught in it. This research employs driving simulation as a means to collect driver response data at the onset of the CY indication to better understand and describe the dilemma zone. The data obtained was compared against that from previous experiments documented in the literature and the evidence suggests that driving simulator data is valid for describing driver behavior under the given conditions. Fuzzy logic was proposed as a tool to model driver behavior in the dilemma zone, and three such models were developed to describe driver behavior as it relates to the speed and position of the vehicle. These models were shown to be consistent with previous research on this subject and were able to predict driver behavior with up to 90% accuracy. / Graduation date: 2013

Thesis (MEng)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Driving is a complex task that requires both the physical ability to drive a vehicle and the cognitive ability to do so safely. The ability to correctly integrate and apply information from the driving environment is essential for safe driving. In South Africa approximately 33 people per 100 000 population are killed annually in road accidents. Recent mortality data from South Africa has indicated that the age group 15 to 19 years old are the age group most likely to be involved in fatal vehicle crashes. Novice driver behaviour has been confirmed as problematic across the globe and extensive research into novice driver behaviour has been conducted to understand and ultimately to curb novice driver deaths. Very little is known about South African novice drivers. This lack of knowledge makes it difficult to plan for training, education or preparing young South African novice drivers for the challenges they are likely to face on the road. This study is a first stepping stone to understand this problem. This study utilises naturalistic driving studies as a method to explore differences between novice and experienced driver behaviour at a few preselected location types. Since 2005 naturalistic driving studies (NDS) have been employed extensively in the rest of the world and this study is South Africa’s first small attempt to employ this methodology and apply it to specifically novice driver behaviour. This thesis therefore not only explores novice driver behaviour in the context of South Africa, but also provides an overview of how the ND methodology can be developed for use in South Africa. The document provides an overview of both novice driver behaviour and naturalistic driving study methodologies from abroad. Where available, reference to South African research and reports are made. The literature review considers demographic, developmental and personality factors that could potentially (and have internationally been proven to) influence novice driver behaviour in the context of society, family and physical environments. Popular theories that have been applied to novice driver behaviour are reviewed. These theories include the Theory of Planned Behaviour, Social Learning Theory and the Theory of Intent. On the methodology side, the technology, its application as well as challenges and successes of the ND methodology are reviewed. The research process is described in terms of the participants and their risk attitudes to road traffic safety prior and after the study. The research process also details the specifications of the technology used, the data collected and the associated processes to make the data manageable. The research process took a number of unexpected turns which included the development of a coding scheme for the image material. Initially it was thought that this coding scheme should be predefined. However once the coding process commenced it was clear that in-vivo coding was necessary for inclusion of all elements of the environment and the behaviour. These elements differed from video to video and participant to participant. Grounded theory was introduced in an attempt to explain the novice behaviour. Although the data analysed was not extensive enough to substantiate the use of grounded theory it is considered useful in operationalizing this coding scheme in future. In addition to learning how to work with the data collection systems and how to integrate different types of quantitative and qualitative data in different formats, it also became clear that a strategy for managing large databases should be considered. This was an unexpected spin-off and is currently being investigated. The findings of the study showed that certain behaviours (such as the left scanning of a driving environment) were neglected not only by novice drivers but also by experienced drivers. Further investigations could include research into understanding this phenomenon. The preselected site types included stop streets, traffic lights, traffic circles and intersections. Traffic lights and intersections in particular have in recent years been highlighted as hazardous locations in Pretoria, where the study took place. Differences in behaviours were highlighted for intersections but not for traffic lights, stop streets or traffic circles. However the difference in the proportion of time that novice and experienced drivers took to scan their environments around these preselected hazardous locations differed significantly. Experienced drivers were much more thorough than their novice counterparts. This study was aimed at investigating the differences between novice and experienced drivers and aimed to develop recommendations that could potentially have implications for changing the driver training and education milieu in SA. However, the sample size (both participants and material selected for analysis) was too small to make meaningful recommendations towards change in this industry. It did however show clear differences between novice and experienced drivers, even in South Africa, and that this research needs to be expanded. The potential of this research for South Africa is enormous and could quite possibly, in future, change the way in which South Africans drive.

Identifying and understanding the relationships between observed driving behavior over long-term periods and corresponding crash involvement rates is paramount to enhancing safety improvement programs and providing useful insights for transportation safety engineers, policy markers, insurance industries, and the public. Unlike previous data collection methods, recent advancement in mobile computing and accuracy of global positioning systems (GPS) allow researchers to monitor driving activities of large fleets of vehicles, for long-time study periods, at great detail. This study investigates the driving patterns of drivers who have and who have not experienced crashes during a 14-month study period using the longitudinally collected GPS data during a six-month Commute Atlanta study. This investigation allows an empirical investigation to assess whether drivers with recent crash experiences exhibit different driving or activity patterns (travel mileage, travel duration, speed, acceleration, speed stability duration, frequency of unfamiliar roadway activities, frequency of turn movement activities, and previous crash location exposures). This study also discusses various techniques of implementing GPS data streams in safety analyses. Finally, this study provides useful guidance for researchers who plan to evaluate the relationships between driver driving behavior and crash risk with large sample data and proposes driving behavior activity exposure metrics of individual drivers for possible safety surrogate measures as well as for driver re-training and education programs.

Thesis (M.S.)--University of Wyoming, 2009. / Title from PDF title page (viewed on July 22, 2010). Includes bibliographical references (p. 137-139).

Thesis submitted to the Division of Science and Engineering. Bibliography: leaves 307-322.

At signalized intersections, pedestrians are considered to be amongst the most vulnerable. When in the crosswalk at intersections without protected left-turn phasing, pedestrians are particularly at risk from left-turning vehicles. Until recently, a wide variety of indications were in use across the US to indicate a permissive left-turn condition to the driver. In Oregon, the Flashing Yellow Arrow (FYA) has been used to indicate the permissive left-turn condition for approximately 10 years. With the addition of the FYA in the 2009 MUTCD, it is likely that its use will continue to increase nationally. Though many operational and safety issues have been studied about the FYA indication, this research proposes to fully investigate factors that influence driver behavior in the context of the permissive left-turn conflict with pedestrians. Specifically, the research seeks to study driver glance behavior to identify reasons why drivers are, "looking at but not seeing" pedestrians in or near the crosswalk or not searching for the presence of pedestrians at all. / Graduation date: 2013

Diss. Tampereen teknillinen korkeakoulu, 2006. / Myös verkkojulkaisuna.