Sheep, cattle, horses (brumbys) and kangaroos have no concept whatsoever of modern motor vehicles.

They have absolutely no way of gauging speed - try this: have someone shine a powerful light into your eyes in the dark and see what you can see...

Nothing.

A 1,000kg wild Brahman bull is not afraid of you or your campervan, and he's not out there on holidays. He lives there, it's his place, so respect his territory, kangaroos are born to hop and jump, usually right through your cars windscreen, so PLEASE drive only during daylight hours and you will see all the scenery tomorrow.