Sleepiness contributes up to 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. This book describes three independent studies which highlight the detrimental influence of sleep deprivation on a range of driving-related processes. Sleep deprivation can have large implications for safe driving, and this study highlights the importance of promoting and educating drivers about the dangers of driving when sleepy.