Aims: To validate a set of simple clinical tests, these could then be used to establish an objective assessment of an individualñs ability to perform an emergency stop safely in orthopaedic clinics. Methods: This prospective ethically approved study involved assessment of emergency breaking reaction times of Right knee arthroscopy patients using a computer linked car simulator designed by Transport Research Laboratory (TRL). The ability to perform an emergency stop was assessed as the time taken to achieve a brake pressure of 200N after a visual stimulus. Each patient was tested preoperatively, 1 day and 1 week after arthroscopy. In addition three speciþcally designed clinical tests were performed, i.e, a) Knee ßexion during single leg stance; b) Active plantar ßexion against the weight of the whole body during single leg stance c) straight leg raise for 10 seconds. Results: In total 31 patients completed the study. The average reaction time preoperatively was 750ms; Correlation between driving reaction times and the results of clinical tests was performed. Statistical analysis revealed sensitivity up to 96%, speciþcity up to 71% and positive predictive value up to 92% for the clinical tests. Conclusions: Ç Doctor when I can drive? È is a common question faced by all orthopaedic surgeons in the clinics. As driving simulators are not available in the clinics it is appropriate for patients to be assessed with these simple clinical tests, to decide the actual timing of return to driving. A similar study involving joint replacement patients is underway.