Drink Driving -
A Complicated Process That Could Convict You

It is illegal to drive if you have taken drugs or alcohol which impair your ability to drive safely. The way this is measured by the police is with an evidential breath test or an evidential blood test. Both can be used as evidence in court but there are some important things to understand.

Let’s start with the basics first.

Maximum Limits

Under New Zealand law the maximum limits are set by age:

  • Under 20 – a zero limit applies.
  • From 1 December 2014 the alcohol limit lowers from 400mcg of alcohol per litre of breath to 250mcg. The blood alcohol limit lowers from 80mg of alcohol per 100ml of blood (0.08), to 50mg (0.05).

Now you can see why there is both a breath and a blood test – failing either is a criminal offence.

Bear in mind that people under 20 are still required to complete a test because the penalties vary depending on the alcohol level. Less than 150 micrograms per litre of breath and less than 30 milligrams per 100 millilitres of blood, means you could be fined and given 50 demerit points. More than that and you could be disqualified from driving, given 50 demerit points and either fined or imprisoned.

For people over 20, from 1 December 2014, if your test result is between 251mcg and 400mcg $200 infringement fee + 50 demerit points (no option to elect a blood test). If you elect to have a blood test because your evidential breath test is greater than 400mcg, but the blood test result is between 51-80mg of alcohol per 100ml of blood, the penalty is an Infringement fee of up to $700 + 50 demerit points.

Accumulate 100 or more demerit points from driving offences within 2 years then you will receive a 3 month driver licence suspension.

Police have a right to stop and screen you when they suspect you are driving under the influence of alcohol and or drugs, or at any checkpoint. Under law, you are obliged to submit to screening and you cannot leave until the testing has been completed.

Stages of Screening

There are several stages of screening:

  1. The Passive Breath Test
    The police officer will place a hand-held device in front of your mouth and ask you to talk into it. This will show if you have recently drunk any alcohol. If any alcohol is detected or you refuse a breath screening test will be required.
  2. The Breath Screening Test
    The police officer will give you a small electronic device, and will ask you to blow into it. If your alcohol level is too high or you refuse, you will be asked to take an evidential breath test or have a blood test.
  3. The Evidential Breath Test
    This is an electronic device you blow into, which gives a reading that can be used in court as evidence of your breath–alcohol concentration. If you refuse, you will be required to give an evidential blood test.
  4. The Evidential Blood Test
    If you have a blood test, a medical doctor or other approved person will take a sample of your blood to be tested for alcohol or drugs.
  5. Additionally there is the compulsory (Drug) Impairment Test
    This includes an eye assessment, a walk and turn, and a one leg stand assessment. If you fail you may be forbidden to drive and required to have a blood test.

The Two Types of Evidential Tests:

You have a right to talk to a lawyer after a breath screening test (the roadside test) and before providing an evidential breath or blood test.

  1. The Evidential Breath Test
    This test can be used as evidence in court (unless you also give an evidential blood test in which case that is used instead). The evidential breath test is done using a more accurate machine either at a police station, or a mobile breath-testing station. If you refuse to take an evidential breath test, you will be required to take an evidential blood test.
  2. The Evidential Blood Test
    You are allowed to choose to have a blood test after a positive evidential breath test. If you do, the results of the evidential breath test cannot be used as evidence in court and the blood test results will be used instead.
    An evidential blood test is given by a doctor or nurse and can be used as evidence in court. If you refuse a blood test you can be fined up to $4,500 or imprisoned for up to three months, and your driving licence suspended for at least 28 days (higher penalties can be imposed for repeat offending).

You will also have to:

  • hand over the keys to your vehicle, if asked by a police officer,
  • go with a police officer, if required.


So now that you understand all that, here’s what you most need to know:

Seven things you need to know that may help you if tested

  1. If the breath screening test taken at the roadside (usually while you are still in your car) indicates you have consumed alcohol, you do have to accompany the officer for an evidential breath test or blood test.
  2. If you fail a roadside screening test, you have a right to speak to a lawyer before you are required to give any evidential test. The police will have a list of lawyers you can call free of charge.
  3. You may refuse to give an evidential breath test but only if you agree to give a blood sample.
  4. If you fail an evidential breath test, you may still ask to give a blood sample if your evidential breath test is above 400mcg. Your evidential breath test will not be used, only your evidential blood test can then be used in court.
  5. Blood samples can be independently analysed later and possibly challenged but evidential breath tests can’t.
  6. Do not refuse to give a blood sample unless you have a genuine reason (e.g. a well-documented phobia of needles) or the penalties can be even more severe.
  7. Take your own written notes of what happens and particularly the process, the timing of events and any pressure or poor treatment you receive. Note details like the time you had to wait for the blood test to be taken, or if you are pressured to give an evidential breath test. Ask the police officer for pen and paper if you don’t have any.

And if you need help, just get in touch.

Email Douglas: douglas@dmlaw.co.nz or direct dial:

09 213 9666 or 021 900 803