This chapter focuses on traffic fatalities and injuries as a public health problem and driver sleepiness involvement in crashes. It explains how physiology and behavior change during sleepy driving and what is the precipitating cause of the impaired behavior involved in a crash. Considering the central role of sleepiness in crash causation, knowledge of the use of countermeasures is an important issue. Apart from driver-initiated countermeasures one may also consider various types of information to the driver about fatigue risks in driving. In order to reduce driver sleepiness, a holistic approach may be a promising strategy that takes technological, organizational and individual factors into account. Evidence-based fatigue management programs are a key factor in this approach and should reassure that professional drivers have the rosters, tools and knowledge to maintain high alertness and safe driving.