Obtaining (and retaining) a drivers license for people who deaf and hearing impaired is same process in Western Australia as anyone else.  Essentially there is no restriction based on hearing to driving a private vehicle.

For the commercial driver, there are some regulations about the level of hearing in the drivers better ear, requiring it to be better than 40dB when averaged.

Why should a drivers hearing be a consideration?

The concern is “responsiveness to critical events is an important safety consideration of commercial vehicles. … to ensure their awareness of changes in engine or road noise. … and of horns, rail crossings, emergency signals and sirens”.  The key principal is that of safety.  Safety of both the public and the driver

So what can you do if you are a commercial driver with hearing loss?

Fortunately, within the Australian Standards, provision is made for conditional license, which may require the driver to wear their hearing aids whilst driving and in some case modify their vehicle with visual aids (for example mirrors to see the back of the vehicle and visual warning signals).