At any time of the day and on any road in the country, police can pull you over for whatever reason – a broken headlight, failing to give way correctly – and ask you to take a breath test. At this point, the police ask you if you have been drinking and when it was that you stopped.
If it turns out your last drink was 10 or 20 minutes before, they will often ask you to wait about 10 minutes before they conduct a test. They do this because the machine they use to test your breath cannot tell the difference between alcohol on your breath and alcohol in your blood stream.
When the police give you the test, and, if you record a positive reading, you will be arrested for the purpose of a breath analysis. Positive readings that will get you arrested are any that are over 0.05 for a fully licenced driver, between 0.02 and 0.05 for special range and anywhere up to 0.02 for a novice driver.
For the purposes of securing a conviction, after they have arrested you, the police must conduct a breath analysis, within 2 hours, for it to be admissible in court. The breath analysis machine is able to differentiate between blood alcohol levels and breathe alcohol levels.
The results of this test are considered to be an accurate representation of the amount of alcohol in your bloodstream at the time of driving. If you find yourself in a situation where you have been charged by the police for a drink driving offence, you should look to find experienced legal advice as quickly as possible.