Untreated Sleep disorders can affect a person’s ability to drive. Read Chapter 8 of Assessing fitness to drive (Published by Austroads) which outlines some sleep disorders that can affect your ability to drive.
“But with the benefits of being able to drive also come certain responsibilities, and one of these responsibilities is to make sure you are well enough to drive safely”. Source: Driving and your health. 2012 Austroads.
“It is the responsibility of the driver to avoid driving if they are sleepy, comply with treatment, maintain their treatment device, attend review appointments, and honestly report their condition to their treating physician”. Source: Assessing your fitness to drive for commercial and private vehicle drivers. 2012. Austroads. Page 107.