Here in Victoria, the leading case defining the meaning of drive is Tink v Francis  2 VR 17. That case was decided by the Court of Appeal, and actually considered three separate appeals. The three appeal justices, Young CJ, McInerney and Southwell JJ, gave separate judgments.
In essence, they said that it is a question of fact if a person is driving a car, so earlier cases didn’t really provide any definitive test. But, they all agreed that a driver needed to have control over a car’s direction and whether it moved or stopped.
Parliament has since inserted s 3AB in the Road Safety Act, which provides:
3AB. Circumstances in which person is to be taken to be driving a motor vehicle
Without limiting the circumstances in which a person is driving a motor vehicle, a person who is steering a motor vehicle which is being towed by another motor vehicle is to be taken to be driving the towed motor vehicle for the purposes of this Act, whether or not the towed motor vehicle has any other means of propulsion and whether or not the person steering it has any control over its means of propulsion.
The South Australian Supreme Court recently considered when a person is driving in Harvey v Police  SASC 302.
In that case, Harvey was the front-seat passenger in a Ford Fiesta. His friend drove a Ford Fiesta to a petrol station, refueled, and went to pay for the petrol. He left the car door open.
Harvey leaned over, with his seat-belt still on, and closed the door. He then turned the ignition key, intending to turn it to accessories so he could turn the radio on. Instead, he turned it one notch too far, to start. The car was in gear, and lurched foward, continued on for about 5 metres (why, doesn’t seem to have been explored at the first hearing) and collided with a metal frame at the console-operator’s window. Harvey tried to steer the car away from the building, but history records that he was not successful.
Harvey was charged with various driving offences, including driving with more than the prescribe concentration of alcohol in his blood. (He had a BAC of 0.25%! That might have had something to do with the whole episode, including that he didn’t try to use the handbrake to stop the car.)
The South Australian Supreme Court considered a number of SA authorities on driving, and drew a distinction between a broader meaning applied in third-party insurance cases, and a narrower meaning applied for criminal cases. Torts lawyers often talk about courts extending or finding liability in certain cases when they know the deep-pockets of insurance companies stand behind the party in a civil proceeding. Most of the reported cases stem from jury trials, so we have no idea what those juries were thinking: but it’s probably a fair conclusion. Indeed, the finding of the Supreme Court in this case supports that conclusion.
After canvassing all the authorities, the Supreme Court considered that — for criminal charges at least — intention to drive was not determinitive, but was a relevant consideration. Additionally, because third-party insurance liability schemes now covered passengers in cars (at least in South Australia), courts didn’t need to find ways of concluding that someone was driving for people injured by the movement of a car to be entitled to compensation.
That meant it wasn’t necessary to give the extended meaning of drive to this case, and Harvey was acquitted of the criminal charges.
This is consistent with Victorian cases such as Woods v Gamble (1991) 13 MVR 153, which hold it’s necessary to show a person intends to start or drive a motor vehicle to be guilty of an offence, at least for drink-driving charges.