Zero drugs; plenty of alcohol

By Anna Sandiford 03/02/2013

It’s always struck me as a bit odd, the disparity between the NZ drug driving law and the drink driving law.

My non-lawyer’s view is that drug driving law stipulates that a person is guilty of the office if their blood contains evidence of a qualifying drug.  This means that if even a small amount of any of the usual drugs of abuse or other drugs such as some prescription medications is found in a person’s blood, and they have also ‘failed’ a compulsory impairment test then the person can be found guilty of the offence.

It’s not as simple as that of course because there are other legal and procedural issues, but the point to make here is that merely the presence of any qualifying drug goes a long way to the likelihood of a successful prosecution.  Even if the concentration of that drug is not sufficient to cause impairment in itself; the analysis at the laboratory does not allow any comment on whether or not the concentration present is capable of causing impairment.  The analysis just has to show whether or not there is any qualifying drug present; there is no requirement to report any concentration of the detected drug/s.

The drug driving law uses a combination of the results of the compulsory impairment tests, the results of which are subjective and based on the experiece of the police officer who conducted them (and who is not usually medically trained) with the results of a blood test that do not have to show a concentration of a drug but just demonstrate the presence of a qualifying drug.

Compare this with the drink driving law, which states that people can legally drive around in their cars with blood alcohol concentrations more than capable of causing impairment but as long as their blood alcohol concentration is below 80 milligrams of alcohol per 100 millitres of blood then they’re not committing an offence.

Seems inconsistent to me to have one drug (alcohol) permitted in blood at a concentration more than capable of causing impairment below a level of 80 mg alc/100 ml blood whilst all other drugs only need to be demonstrated to be present, along with a ‘failed’ impairment test.

A lower legal blood alcohol concentration would seem, to me, to bring the drink driving law more in line with the drug driving law.

0 Responses to “Zero drugs; plenty of alcohol”

  • The difference is one is legal, with a zero limit under 20 and a limit after that age (with the recommendation that the sensible course of action is not to drive after drinking). The law may be that way because there needs to be balance between engaging in a legal activity and the consequences of that – I’d agree that review and reduction might be necessary for alcohol given that at the high end of the limit impairment would most likely be there. The penalties vary for levels in blood which correspond to levels of intoxication and competence to drive.

    With drugs, it’s driven by suspicion of impairment so it’s not quite correct to put it in the way you have as the person must at least be visibly impaired in some way first and foremost, then further testing is done, then based on those results prosecution may occur. This information states with the 2009 law change which meant people could actually be prosecuted for drug driving – “The presence of a qualifying drug alone *is not* sufficient for an offence; there must first be impairment as demonstrated by unsatisfactory performance of the compulsory impairment test.” If impairment is the reason for the test being done in the first place, exact blood levels detected are moot. The person concerned was judged as driving while impaired which is the breach in law, the thing they’d be looking for is the particular drug concerned in the evidential drug test. Another thing I think a lot of people miss is that polypharmacy is fairly common and people can have taken combinations of varying amounts of both drugs and alcohol at the same time along with there being such a wide variety of drugs out there that setting limits would seem to be impracticable with the exception of the one legal one.

    The impairment test is not totally subjective IMO, it’s based on…”a test used in the UK and adapted for the New Zealand Police by experts from Swinburne University of Technology, Melbourne.” (from the previous link) and it at least provides some reasonably objective measures e.g. “measure the person’s pupils by comparing them with a gauge held beside the person’s eyes” If the blood test is clear, it’s clear irrespective and the officer is meant to inquire as to problems such as disabilities that can cause problems in testing for impairment.

    For prescription medicines, not only the law is clear that it is illegal to drive while impaired the labelling as well as information given states clearly that the medication can cause impairment and not to drive or operate machinery while using it. if you ignore this, then the onus is on the individual. I doubt if they could prove otherwise that they were using the drug in accordance to instructions and labelling, but that defence is allowed.

    I don’t think this is inconsistent at all really, the principle should be to prosecute drugged driving as you would drink driving. Prior to 2009, there was nothing to stop this and this did need to be rectified.

    • Thank you for your comments, with which I largely agree. Sometimes, a blog post is briefer than ideal.
      In the course of casework (here and overseas) I have encountered issues with variability (i.e. subjectivity) in the way Police impairment tests are conducted and, largely because this gets rid of certain defence arguments, I prefer the English system where the driver also has to be examined by a medic so they can exclude any medical condition as being a cause of/contributor to the observed impairment.
      Overall, I personally would prefer to see a reduction in the legal blood/breath alcohol levels for driving. England and Wales have a breath limit of 350, compared with NZ’s 400, simply because they used a different blood:breath ratio and came up with a lower breath concentration as a result. In the meantime, we work with what the law currently provides.