Understanding hazard perception in filmed and simulated environments

Each year millions of people around the world are killed or injured due to being involved in collisions while driving on the roads, with young and inexperienced drivers most likely to be killed or injured. Numerous studies have found a link between the likelihood of a driver being involved in a collision and their hazard perception (HP) ability, with young and inexperienced drivers having inferior HP abilities compared to older and more experienced drivers. This thesis presents a series of studies that investigate the factors that affect HP performance as well as comparing different HP testing methods. The traditional video-based method is explored as well as new methods utilising a high-fidelity driving simulator (used as an analogue of real-world driving) in order to see if there are ways of making HP testing more representative of detecting and responding to hazards while driving on the road. This thesis also explores the use of functional near-infrared spectroscopy (fNIR) as a portable and flexible means of measuring dorsolateral prefrontal cortex (DLPFC) activity during driving. Comparisons between video-based HP testing (similar to that used in the UK HP test) and simulator-based HP testing revealed significant differences in psychophysiological and behavioural responses, indicating that video-based methods may not be representative of HP while driving on the road. fNIR was found to primarily measure task workload and to be a reliable means of recording DLPFC activity across a range of different driving tasks. The fNIR results also demonstrated that DLPFC was similar when performing a simulator-based HP test and a hybrid simulator method using simulation replays, suggesting that introducing elements of driving simulation may help bridge the gap between current video-based HP testing methods and HP while driving on the road. These findings have important implications for the theoretical and practical aspects of HP testing and the use of fNIR in driving research

Understanding hazard perception in filmed and simulated environments

Each year millions of people around the world are killed or injured due to being involved in collisions while driving on the roads, with young and inexperienced drivers most likely to be killed or injured. Numerous studies have found a link between the likelihood of a driver being involved in a collision and their hazard perception (HP) ability, with young and inexperienced drivers having inferior HP abilities compared to older and more experienced drivers. This thesis presents a series of studies that investigate the factors that affect HP performance as well as comparing different HP testing methods. The traditional video-based method is explored as well as new methods utilising a high-fidelity driving simulator (used as an analogue of real-world driving) in order to see if there are ways of making HP testing more representative of detecting and responding to hazards while driving on the road. This thesis also explores the use of functional near-infrared spectroscopy (fNIR) as a portable and flexible means of measuring dorsolateral prefrontal cortex (DLPFC) activity during driving. Comparisons between video-based HP testing (similar to that used in the UK HP test) and simulator-based HP testing revealed significant differences in psychophysiological and behavioural responses, indicating that video-based methods may not be representative of HP while driving on the road. fNIR was found to primarily measure task workload and to be a reliable means of recording DLPFC activity across a range of different driving tasks. The fNIR results also demonstrated that DLPFC was similar when performing a simulator-based HP test and a hybrid simulator method using simulation replays, suggesting that introducing elements of driving simulation may help bridge the gap between current video-based HP testing methods and HP while driving on the road. These findings have important implications for the theoretical and practical aspects of HP testing and the use of fNIR in driving research

Prefrontal cortex activation and young driver behaviour: a fNIRS study

Road traffic accidents consistently show a significant over-representation for young, novice and particularly male drivers. This research examines the prefrontal cortex activation of young drivers and the changes in activation associated with manipulations of mental workload and inhibitory control. It also considers the explanation that a lack of prefrontal cortex maturation is a contributing factor to the higher accident risk in this young driver population. The prefrontal cortex is associated with a number of factors including mental workload and inhibitory control, both of which are also related to road traffic accidents. This experiment used functional near infrared spectroscopy to measure prefrontal cortex activity during five simulated driving tasks: one following task and four overtaking tasks at varying traffic densities which aimed to dissociate workload and inhibitory control. Age, experience and gender were controlled for throughout the experiment. The results showed that younger drivers had reduced prefrontal cortex activity compared to older drivers. When both mental workload and inhibitory control increased prefrontal cortex activity also increased, however when inhibitory control alone increased there were no changes in activity. Along with an increase in activity during overtaking manoeuvres, these results suggest that prefrontal cortex activation is more indicative of workload in the current task. There were no differences in the number of overtakes completed by younger and older drivers but males overtook significantly more than females. We conclude that prefrontal cortex activity is associated with the mental workload required for overtaking. We additionally suggest that the reduced activation in younger drivers may be related to a lack of prefrontal maturation which could contribute to the increased crash risk seen in this population

fNIRS probe placement.

<p>(a) Positioning of the 4 light sources (red) and 10 detectors (blue) with references to the nasion. (b) Sensitivity profile of the fNIRS probe used in this experiment projected onto a digital brain atlas based on the “Colin27” atlas [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0156512#pone.0156512.ref057" target="_blank">57</a>] commonly used in MRI studies. The colour scale depicts the sensitivity logarithmically. Both images were created using AtlasViewerGUI [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0156512#pone.0156512.ref058" target="_blank">58</a>].</p

PFC activation of younger and older drivers.

<p>Channel by channel activation maps showing greater activity in older drivers (a) than younger drivers (b). Z-scores represent change from resting baseline.</p

PFC activation during overtaking and following tasks.

<p>Channel by channel activation maps showing greater activity in the PFC during overtaking tasks (a) than following tasks (b). Z-scores represent change from resting baseline.</p

NASA-TLX Inhibitory Control scores.

<p>Graph shows age by experience interaction (a) Older experienced drivers reported higher levels of inhibitory control in both the following and overtaking conditions when compared to younger experienced drivers. (b) No differences between older and younger novice driver ratings of inhibitory control. Error bars represent standard error of the mean.</p

NITES 2 driving simulator and fNIRS apparatus.

<p>Photograph of the experimental setup. The participant is driving along the single carriageway road used in this experiment. The fNIRS computer is shown on the right; during the experiment this was positioned behind the participant out of their field of view.</p

PFC activation by hemisphere.

<p>Channel by channel activation map showing greater activity in the right hemisphere of the PFC than the left, measured across all tasks. Z-scores represent change from resting baseline.</p