The casualty may be able to be treated. Female marsupials very often have pouch young which can be saved. Injured and orphaned animals require special treatment. They will advise you how to care for the animal or find foster parents for it. If you choose to hand-raise the orphan yourself, keep in mind that permits are required.
Rangers remove dead animals from roads around national parks reserves.
This helps stop Tasmanian devils and other scavenging animals such as the threatened wedge-tailed eagle from being killed when they are feeding off a road kill. If you remove an animal from the road consider your own safety.