Exploring the interaction of distraction and passenger presence in relation to drivers’ road traffic collision risk and hazard perception performance

This thesis investigates the impact of distraction and passenger presence on driving performance and road traffic collision (RTC) risk, recognising human error as a primary cause of RTCs. Distraction is a significant factor in RTCs. While distractions like conversation and radio listening are known to depreciate driving performance and increase RTC risk, the influence of passengers on RTC risk remains debated.
Three experiments were conducted. Initially, distraction's effect on visual detection in an abstract context was explored to isolate distraction's impact from drivers' mental models of driving. Results indicated that more complex distraction tasks significantly impaired visual performance. Subsequently, RTC risks were analysed with and without distraction and passengers. Findings suggested differences in RTC risk among driver-passenger age groups, particularly for young drivers with young passengers.
The final experiment, influenced by the previous studies within this thesis, involved drivers performing a hazard perception task while distracted by a passenger seated either in the front or rear. The distraction task mirrored the highest complexity from the visual detection experiment, and the sample comprised the highest-risk group (young driver and young passenger). No significant differences were found in hazard perception performance between front and rear passengers, except for reaction time, which was slower with a front passenger.
These findings contribute to understanding distraction's impact on driving performance and RTC risk, particularly regarding passenger presence. The thesis provides a deeper exploration into these results, offering additional insights and discussions related to existing theories and research. Overall, the research highlights the complex interplay between distraction, passengers, and driving performance, providing valuable implications for road safety initiatives.