The decision about whether or not someone remains fit to drive is often a difficult  one. Although having been given the responsibility for making fitness to drive decisions, medical professionals often feel ill equipped to make evidence based decisions in the clinical setting. Therefore, the treating professional is often required to make recommendations based upon subjective clinical judgement, putting their relationship with the client under pressure. 

The publication "Assessing Fitness To Drive"  produced by Austroads provides some guidance on this matter.   However, useful as it may be, there are limitations to these guidelines. These limitations are serious for large subsets of the driving population in need of medical fitness-to-drive assessments. Seniors provide a common example. Most seniors have not one, but several medical conditions. To compound things, seniors also typically take several prescription medications as well as several over-the-counter medications. The problem becomes apparent when you consider that the effects of any single medical condition on the person’s competence to drive may be altered dramatically by co-existing illnesses and treatments. The effects of chronic conditions combine, often in largely unknown ways, and those interactive effects are further modulated by age, medications, and other factors, to substantially alter the functional outcome for individuals beyond what it would be from an isolated illness. For seniors, this medical complexity is the rule, not the exception

The Australian Medical Association has made the following statement:

“Medical assessment for fitness to drive needs to be available independently of the patient's normal practitioner to avoid the conflict situation of the caring practitioner also having to adjudicate on fitness to drive” (AMA 2008)