The evolution of society and labor organization (24/7 working) has significantly changed our lifestyles and increased the number of workers with sleep debt and staggered hours. Populations are particularly at risk of excessive sleepiness due to sleep deprivation (professional obligations), circadian factors (e.g. night driving) and sleep disorders (e.g. obstructive sleep apnea syndrome and hypersomnia). Excessive daytime sleepiness (i.e. difficulty staying awake) is estimated to affect about 5 % of the population. Public health studies have shown that sleepiness at the wheel and other risks associated with sleep are responsible for 5% to 30% of road accidents, depending on the type of driver and/or road. Strategies to reduce accidents related to sleepiness include--reliable diagnosis and treatment of sleep disorders,--management of chronobiological conflicts,--adequate catch-up sleep, and--countermeasures against sleepiness at the wheel.