Traffic Act 1925

Where a police officer is of the opinion that a person who is for the time being in charge of a motor vehicle is, by reason of his physical or mental condition, however arising, incapable of having proper control of the motor vehicle, the police officer may – forbid that person to drive the motor vehicle; direct that person to deliver up to the police officer forthwith all ignition keys and other keys of the motor vehicle that are in that person's possession; and take such steps as may be necessary to render the motor vehicle immobile or to remove it to a place of safety.

A person who fails to comply with a direction given to him under subsection (1) or does an act that is for the time being forbidden under that subsection is guilty of an offence against this Act, but no person shall be convicted of an offence under this subsection unless the court before which he is charged is satisfied that the police officer had reasonable grounds for believing that, in all the circumstances of the case, the direction or prohibition was necessary in the interests of the defendant, or of any other person, or of the public.

Subject to subsection (4), where a police officer exercises the powers conferred by subsection (1), he shall retain the ignition keys and other keys of the motor vehicle and cause the motor vehicle to be kept immobile or in a place of safety until such time as, in his opinion, the person referred to in the last-mentioned subsection is capable of having proper control of the motor vehicle.

Notwithstanding anything in subsection (3), a person who is directed or forbidden to do anything, pursuant to subsection (1), may, at the time when the direction or prohibition is given or imposed or at any time thereafter, request that – his capacity to have proper control of the motor vehicle be determined by a police officer (in this subsection referred to as "the senior police officer") of a higher rank than the police officer who gave the direction or imposed the prohibition, if the last-mentioned police officer is of a rank lower than inspector; or he be permitted to submit himself for examination by a medical practitioner – and if it is reasonably practicable that the request be granted the police officer who gave the direction or imposed the prohibition shall make the necessary arrangements accordingly, and if the senior police officer or the medical practitioner, as the case may be, certifies that he is of the opinion that that person is capable of having proper control of the motor vehicle, the police officer who has possession of the ignition keys and other keys of the motor vehicle shall forthwith return them to that person and, if the motor vehicle has been rendered immobile, shall also without further delay cause it to be again returned to running order.