The aim of this study was to compare metropolitan on-road driving performance in patients with severe obstructive sleep apnea (OSA) and healthy age-matched controls. A driving assessor-based on-road driving test was performed at 2.00 pm in severe OSA patients and age-matched healthy controls. Main outcome measures included passing or failing the test, occurrence of minor traffic faults (e.g. not indicating, late braking, mirror checking) and traffic law infringements (e.g. failing to stop or give way, speeding). Compared to controls, there was no evidence of gross driving impairment or higher driving test failure rate in OSA patients. However, OSA patients demonstrated ~60% more traffic law infringements (11.0 ± 1.8 versus 6.8 ± 1.0% of general driving tasks, p= 0.024), primarily reflecting repeated failure to stop at stop signs and/or traffic lights (p= 0.037). Patients with severe OSA break road laws more frequently than age-matched controls during a short city driving test, suggesting greater inattention and thus potentially higher motor vehicle accident risk. Further studies are needed to extend these early findings, which raise serious clinical and road safety concerns.