Vigilance decrement during the on-the-road driving tests: The importance of time-on-task in psychopharmacological research

► Driver sleepiness significantly impairs driving performance, and is the cause of about one in five traffic accidents. ► Driver sleepiness can be caused by many factors, of which time-on-task is an important one. ► The 100-km on-the-road driving test is ideal to monitor the impact of CNS-drugs on performance decrement over time. ► After both placebo and drug treatment performance decrement over distance traveled is seen. ► If driving tests are too short in duration, increased motivation and associated increased effort may counteract the impairing effects of a drug.