What is the legal consequence if a driver refuses to provide a specimen of breath or blood when lawfully requested by a police officer?

1. Refusal is lawful, and the officer must instead prove impairment by observation alone
2. Refusal is an offence in its own right, penalised on the same footing as driving over the prescribed limit, with heavy fines and disqualification
3. Refusal is permitted once, and only a second refusal within twelve months is an offence
4. Refusal is excused if the driver later provides a specimen at a private clinic