Police Weapons: Australia | Law Library of Congress
The best bit is
(b) if the person is attempting to escape arrest by fleeing—do such a thing unless:
(i) the constable believes on reasonable grounds that doing that thing is necessary to protect life or to prevent serious injury to another person (including the constable); and
(ii) the person has, if practicable, been called on to surrender and the constable believes on reasonable grounds that the person cannot be apprehended in any other manner.
[53]
So you have to read it all to get the context. But I read it as the cops can do whatever necessary - while using minimal force to apprehend the baddies.
So handcuffs prior to arrest could be reasonable for the purposes of apprehending them. Now given this guy turned off the road into a service station at 2am - maybe the cops saw this as an attempt to abscond - hence need for handcuffs to apprehend.
Now if it is a copper alone - like highway patrol and he intended to search the car - then cuffing the baddie in order to execute the search without concern old mate was gonna do a runner, would seem reasonable...