1. Understand what can happen if you break the law

If the police think you've been driving while impaired by cannabis, they can:

• immediately suspend your driving licence
• give you a fine
• take away your vehicle and send it to a pound
• charge you with an offence that could lead to a criminal record
• charge you with an offence that could lead to time in jail

To do this, the police must have reasonable grounds to believe you're impaired by cannabis.

There are several types of criminal offences related to cannabis. The offence that you could be charged with depends on how impaired you are. 

THC levels in blood

THC is the main thing in cannabis that affects your mental state. It is a criminal offence to have a blood alcohol level above a specific limit within 2 hours of driving. There are similar rules for cannabis.

If within 2 hours of driving you have a level of THC in your blood that is over the specific limits, you can be charged with a criminal offence. The type of offence depends on the THC level:

• If you have 2 ng to 5 ng of THC per ml of blood, you can be charged with a summary offence with a fine of up to $1,000.
• If you have 5 ng or more of THC per ml of blood, you can be charged with a hybrid offence.
• If you have a blood alcohol concentration of 50 mg of alcohol per 100 ml of blood, combined with a THC level greater than 2.5 ng per ml of blood, you can be charged with a hybrid offence.