Lapses of attention are characteristic for attention-deficit/hyperactivity disorder (ADHD) and as such may impair performance of daily activities. Data from an on-road driving study were reanalyzed to determine lapses in patients with ADHD after treatment with methylphenidate and placebo.A total of 18 adult ADHD patients performed a 100-km on-road driving test and were instructed to drive with a steady lateral position and constant speed. The SD of lateral position (SDLP), that is, the weaving of the car, lapses, and alertness, was assessed.Driving was significantly better (P = 0.006) with methylphenidate (SDLP, 18.8 cm) when compared with placebo (SDLP, 21.2 cm). Both the reduction in SDLP and the number of lapses (P = 0.003) confirm this significant improvement, which is further supported by subjective assessments of perceived driving performance. Although lapses were common in the placebo condition (11/18 patients), they were much less frequently observed (5/18 patients) after treatment with methylphenidate. Postdriving assessments suggest that lapses often go unnoticed by drivers.In conclusion, methylphenidate significantly improves driving of patients with ADHD by significantly reducing the number of lapses.