Most certification examinations of commercial drivers are simple, and relatively few drivers are disqualified. If these examinations are not done properly, however, the public can be exposed to potentially unqualified drivers. Should an accident occur, the physician who examined the driver may be found liable. In performing driver certification examinations, the physician's primary responsibility is to the public. The Federal Motor Carriers Safety Regulations and supporting documents provide guidelines for the conditions that may be disqualifying and the conditions that may allow only temporary certification until better medical control is achieved. Some medical diagnoses, such as insulin-requiring diabetes mellitus, are automatically disqualifying, no matter how well the disease is controlled. Other conditions may require documented clearance from a specialist before certification is granted.