Browsing by Subject "uneliaisuus"

Objectives Fatigue is a major factor affecting driving performance and traffic accident risk. Driving conditions influence how people experience fatigue while driving. Driving in demanding conditions may increase vigilance in tired drivers; however, it may also increase cognitive load and become an additional source of fatigue. The current study investigated how driving on a slippery road interacts with fatigue caused by sleep deprivation and how it influences driving performance. Methods Twelve male participants (aged 19–21) drove 52.5 km in a driving simulator in four different conditions (day vs night and dry vs slippery road). Subjective sleep-related fatigue was measured with the Karolinska Sleepiness Scale and physiological fatigue in blink durations with electro-oculography. Three measures were used for driver performance: standard deviation of lateral position, mean steering wheel movement amplitude and mean steering wheel movement peak velocity. After each driving session, participants negotiated a cone track. The success rate for this task was analysed separately. Results Driving on slippery roads improved performance in all three performance metrics in sleep-deprived drivers. The three-way interaction between driver condition, road condition and time-on-task was significant for subjective sleep-related fatigue but not for performance. Sleep-deprived drivers became increasingly sleepy over time when driving in slippery conditions; however, this did not negatively affect their performance. Conclusions Driving in demanding weather conditions can increase the fatigue experienced by drivers; however, this change may not be initially detectable in performance. Large individual variability in response to both fatigue and driving conditions requires further research.