The role of physicians in deciding whether a patient should continue to drive is purely advisory. However, physicians have a moral and, in some states, a legal obligation to report patients who are no longer fit to drive. The most authoritative test to predict safe driving in the elderly is an on-road evaluation conducted by the state driver's licensing authority, which has ultimate responsibility for deciding a patient's fitness to drive. Patients with mild dementia are generally considered safe drivers, although specialized testing, such as an on-road test, may be indicated. Those with moderate dementia can be further evaluated by the on-road test, since psychological testing to distinguish moderate from mild dementia is imprecise. Severe dementia is generally considered a contraindication to driving. When a patient is deemed unfit to drive, the physician can provide counseling and support to help ease the transition away from driving.