In which scenario would a driver be allowed to be certified for only 3 months?

A driver would be certified for only 3 months when they are pending results of a sleep study. This scenario reflects a precautionary approach to ensuring the driver's health and safety. Sleep disorders can significantly impair a driver's ability to operate a vehicle safely, and until the results are available, it is prudent to limit the duration of certification. This allows for a re-evaluation of the driver's condition once the medical information from the sleep study is obtained, helping to ensure that any potential health issues affecting their driving capability are addressed promptly.

In contrast, after a minor surgical procedure and showing significant improvement in health might not necessarily require limited certification, as long as the driver meets the medical standards. Additionally, being symptom-free for over 6 months suggests that there are no ongoing concerns that would justify a short-term certification. In cases where the driver's health shows stable improvement or a substantial period of symptom resolution exists, longer certifications can typically be granted. Thus, the need to only issue a 3-month certification when results of a sleep study are pending is aligned with the best practices in medical evaluations for drivers.