Irrespective of national guidelines for medical fitness to drive, this study investigated the cumulative expert wisdom of clinicians regarding minimum periods of driving cessation required for patients suffering from conditions that can impair driver capability. Occupational Physicians (196) and Psychiatrists (103) completed an online questionnaire. For private motorists, the modal response for anxiety and depression favoured clinical discretion, followed by three month cessations for hypomania, acute psychosis, schizophrenia and alcohol dependence and six weeks for alcohol misuse/dependence. For professional drivers the modal value for anxiety and depression was three months, rising to six months for hypomania, psychosis and schizophrenia and 12 months for both alcohol misuse/dependence. Chi-square test results indicated statistically significant differences in clinical opinion between Occupational Physicians and Psychiatrists regarding driving cessation times for drivers suffering from psychiatric and alcohol misuse conditions except for alcohol dependence. Further studies are warranted to investigate these issues in more depth.