At the roadside the police will usually ask you to blow into an initial breath test device (sometimes called a sniffer). This device gives a rough detection as to whether you have been drinking alcohol or not.

If the device indicates that you have, you will likely be asked to provide an evidential breath test. This could be on a booze-bus if you are stopped at a police checkpoint or it could be back at a police station.

If an officer requests, you are legally required to accompany that officer to the police station or booze-bus for the purpose of the test. It is an offence not to accompany the officer.

You are not legally obliged to provide a breath sample (but it is advisable that you do). If you do not provide a breath sample the police officer will tell you that he or she now requires you to provide an evidential blood sample. The police will contact an on-call doctor or nurse who will come to take a blood sample from you. If you do not provide a blood sample you will be charged with Refusing to Provide a Blood Sample. This is a more serious offence and carries a mandatory loss of licence.