Imperial Acts Application Act 1980
See s12,
12. That all grants and promises of fines and forfeitures of particular persons before conviction, are illegal and void.
https://www.thecommonwealthofaustralia.com.au/imperial-acts-application-act-1980/
117 Rights of residents in States.
A subject of the Queen, resident in any State, shall not be subject in any other State to any disability or discrimination which would not be equally applicable to him if he were a subject of the Queen resident in such other State.
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BILL OF RIGHTS 1688 1 WILL AND MARY SESS 2 C 2 – SECT 12
Grants of forfeiture
That all grants and promises of fines and forfeitures of particular persons before conviction are illegal and void.
https://www.thecommonwealthofaustralia.com.au/bill-of-rights-1688/
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International Covenant on Civil and Political Rights
Article 15
1 . No one shall be held guilty of any criminal offence on account of any act or omission which did not constitute a criminal offence, under national or international law, at the time when it was committed. Nor shall a heavier penalty be imposed than the one that was applicable at the time when the criminal offence was committed. If, subsequent to the commission of the offence, provision is made by law for the imposition of the lighter penalty, the offender shall benefit thereby.
2. Nothing in this article shall prejudice the trial and punishment of any person for any act or omission which, at the time when it was committed, was criminal according to the general principles of law recognized by the community of nations.
Australian Road Rules
https://pcc.gov.au/uniform/Australian-Road-Rules-9June2023-bookmarked.pdf
This is a consolidated version of the Australian Road Rules. These Rules are a national
model law and are intended to provide the basis for nationally consistent road rules.
These Rules do not, by themselves, have any legal effect.