What is blood alcohol limit?

The blood alcohol concentration (BAC) limit for drivers in Australia is 0.05 grams of alcohol per 100 millilitres of blood for fully licensed drivers in most circumstances. The 0.05 limit has applied across all Australian jurisdictions since 1991, when Tasmania became the last state to lower its limit from 0.08.

Several categories of driver have a stricter zero BAC limit. Learner permit holders, provisional licence holders (both P1 and P2), drivers of taxis, ride-share vehicles, hire cars, public buses, school buses, and most trucks (heavy vehicles over 13.9 tonnes), and driving instructors must all maintain a BAC of 0.00 while driving. Drivers carrying placarded dangerous goods also face zero BAC. The purpose of the lower limit for inexperienced and professional drivers is to manage the higher crash risk these groups face.

Police enforce BAC limits primarily through random breath testing (RBT), introduced in Australia in 1976 (NSW) and now used routinely across all states and territories. Police can stop any driver and require a preliminary breath test using a portable device. If the test is positive, the driver is taken to a police station or breath analysis vehicle for an evidentiary breath test. Drug driving tests now operate alongside BAC tests in most states, screening for cannabis (THC), amphetamine, and MDMA in saliva.

Penalties for drink driving scale by BAC level and prior record. A first low-range offence (BAC 0.05 to 0.079) typically results in a fine of 600 to 1,800 dollars and a licence suspension of 3 to 6 months. Mid-range (0.08 to 0.149) and high-range (0.15 and above) offences carry escalating fines, longer disqualifications, mandatory alcohol interlocks for repeat offenders, and potential prison sentences. Refusing a breath or drug test is treated as if the driver had the highest-range result. Across Australia, drink driving is implicated in about 30 per cent of fatal crashes, and zero-BAC campaigns continue to be a major focus of state road safety strategies.