Drugged Driving

February 7th, 2012 at 9:08 am by David Farrar

Michelle Duff at Stuff reports:

Dreamy, clammy, drooling or overemotional – the tell-tale signs of a drugged driver have led to hundreds of people being netted since the new laws were introduced.

Figures released to The Dominion Post under the Official Information Act show 514 people appeared sufficiently out of it for police to perform a compulsory impairment test on them since the Land Transport Amendment Act was introduced in November 2009.

Of these, 455 struggled to walk nine steps and turn without wandering off the line – stopping, miscounting the number of steps, not understanding the instructions or having to use their arms for balance.

Under the law, a police officer who suspects a driver of being impaired can require the driver to carry out a compulsory impairment test. This measures co-ordination, physiological reactions and markers for drug impairment such as pupil dilation.

As well as requiring them to walk in a straight line, police must check the driver’s behaviour against a list of possible signs of drug use – including slurred or incoherent speech, dilated pupils, and flushed or clammy skin.

They might also be making jerky movements, drooling, scratching, or appear dreamy or anxious.

A driver who fails must undergo a blood test and can then be charged with driving while impaired, which carries similar penalties to those for drink-driving.

Of the 455 drivers who failed the impairment test since 2009, 429 tested positive for one or more .

I was a long time advocate that the Police should check drivers not just for excess alcohol, but for drugs which impair driving ability. It is good to see that the law change has produced results. Driving while stoned is a very very stupid thing to do, as responses are so slowed.

12 Responses to “Drugged Driving”

  1. swan (777 comments) says:

    “Driving while stoned is a very very stupid thing to do, as responses are so slowed.”

    Evidence? If you are talking about marijuana specifically I don’t think this is generally correct. Certainly less so than 79mg/dl of blood alcohol.

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  2. beautox (500 comments) says:

    When I was young I went to a Police open day when I was stoned out of my brains on pot. My friend who went with me was not stoned, but had drunk one small bottle of beer. They had a reaction tester set up on a motorbike and the cop running it was telling everyone that he would be able to tell if we’d drunk even the smallest amount.

    Well my reactions were completely normal, but my friend was about 40% worse than normal – even with just one beer!

    So, going on this admittedly small sample, being stoned does not slow down your reaction.

    Now as for driving while stoned on pot, I have a lot of experience of this as well. The effect is to make you a slow, careful and highly concentrated driver. I never had an accident in more than 20 years of doing this (I don’t smoke anymore). But I would never drive drunk as that is truly dangerous. I had one experience of that when young and never did it again.

    I can’t comment on other drugs. I suspect P would not mix well with driving…

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  3. Ed Snack (2,792 comments) says:

    A good test for a stoned driver, offer them some food. Anyone showing signs of having the munchies is a sure candidate for further testing.

    I’d have to say if you are acting as noted above, slurred speech, drooling, unable to walk in a straight line or count steps, you’d be pretty far gone. Anxious though, easy to be anxious if you’ve been stopped. You might well be a cautious and careful driver, certainly in my experience cannabis does not make you reckless, but generally I’d reckon that you’d lose the ability to react appropriately in extreme situations. Of course if you’re really trashed there’s no way you will usually drive because it’s just too much trouble, unless there’s an all-night dairy down the way where they have chocolate and ice-cream…

    I knew someone who was recruited to take part in a series of double blind experiments on driving under the influence of alcohol and cannabis. The were given a glass (or glasses) of a heavily scented liquid that might contain alcohol, and smoked a hand rolled cigarette; then drove (on Pukekohe racetrack I think) and had their reactions monitored. The results were basically that alcohol was a lot worse than cannabis, but both was worst. He reckoned though that you could almost always tell if you were given alcohol (tasted different enough), but that the fake weed was quite convincing. Several people apparently acted quite stoned when given the fake, to the subsequent amusement of the experimenters.

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  4. Longknives (6,396 comments) says:

    Gotta love stoners! They will even argue that their ‘Sacred Herb’ not only cures cancer…but makes them better drivers as well!

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  5. Griff (13,845 comments) says:

    United Kingdom Department of Environment, Transport and the Regions, Road Safety Division Cannabis and Driving: A Review of the Literature and Commentary. . “Overall, we conclude that the weight of the evidence indicates that … there is no evidence that consumption of cannabis alone increases the risk of culpability for traffic crash fatalities or injuries for which hospitalization occurs, and may reduce those risks.”
    Canadian Senate Special Committee on Illegal Drugs. 2002.
    Cannabis: Summary Report: Our Position for a Canadian Public Policy. Ottawa.
    “Cannabis leads to a more cautious style of driving, [but] it has a negative impact on decision time and trajectory. [However,] this in itself does not mean that drivers under the influence of cannabis represent a traffic safety risk. Cannabis alone, particularly in low doses, has little effect on the skills involved in automobile driving.”

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  6. Alan Wilkinson (2,435 comments) says:

    The article omits to say what level of drug constitutes a performance issue. Since tests can be extremely sensitive and detect cannabis for many days after use this seems to be an important logic gap which could open the door to police harassment and corruption.

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  7. Longknives (6,396 comments) says:

    It’s quite bloody simple. Do whatever you like in your spare time but for Christ’s sake don’t get behind the wheel when impaired by drugs or alcohol…

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  8. Will de Cleene (470 comments) says:

    There’s a difference between consumption and impairment. From NORML NZ’s submission on drugged driving in 2007:

    Many studies have shown little to no link between cannabis consumption and increased accident rates. For example, a 2002 paper by Chesher and Longo concluded, “The results to date of crash culpability studies have failed to demonstrate that drivers with cannabinoids in the blood are significantly more likely than drug-free drivers to be culpable in road crashes.”

    According to the UK’s Transport Research Laboratory, drivers under the influence of alcohol tend to be more risky in their driving, consumers of marijuana compensate for their intoxication by driving more cautiously. As New Zealand comedian Jeremy Elwood once observed, “If you smoke and drive, you’re a bloody slow driver.”

    NORML would like to draw the select committee’s attention to the latest relevant study conducted by Grotenhermen, et al, recently published in the medical journal, Addiction (August 2007). The Grotenhermen study concludes that “serum concentrations of THC below 10 ng/ml are not associated with an elevated accident risk.”

    NORML tentatively supports a limit of 10 nanograms of THC per millilitre of blood as the threshold for cannabis impairment. Grotenhermen’s research concludes that a level of 10ng/ml corresponds under similar intoxication indicators (such as the BAC) to a level of 0.05 percent alcohol in many European countries. NORML would be more supportive of a level comparable to New Zealand’s alcohol limit.

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  9. john.bt (170 comments) says:

    I passed a woman the other day who was reading a book while driving at about 100 kph. I think that is called brain-impaired.

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  10. Weihana (5,393 comments) says:

    swan (222) Says:
    February 7th, 2012 at 9:41 am

    “Driving while stoned is a very very stupid thing to do, as responses are so slowed.”


    DPF might have based that assertion on a 2001 UK TRL study.

    The report concludes:

    “Both simulation and road trials generally find that driving behaviour shortly after consumption of larger doses of cannabis results in (i) a more cautious driving style; (ii) increased variability in lane position (and headway); and (iii) longer decision times”

    It also states:

    “In conclusion, cannabis impairs driving behaviour. However, this impairment is mediated in that subjects under cannabis treatment appear to perceive that they are indeed impaired. Where they can compensate, they do, for example, by not overtaking, by slowing down and by focusing their attention when they know a response will be required. However, such compensation is not possible where events are unexpected or where continuous attention is required. Effects of driving behaviour are present up to an hour after smoking but do not continue for extended periods.”

    So it does impair driver ability but in a different way and in manner that gives users some ability to compensate. But regardless still better to drive sober.

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  11. swan (777 comments) says:

    @ Weihana,

    Yes well it is all relative. DPF has argued here before that there is no problem after driving having drunk over half a bottle of wine, and that the current 80mg/dl limit is fine. So he seems to think that driving stoned is equivalent to drinking >> a bottle of wine. And the study you link to doesnt appear to support that conclusion.

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  12. Muzza M (312 comments) says:

    In my previous occupation I witnessed people consuming enough methadone to kill me five to 10 times over, but still allowed to drive. I don’t think it should be allowed.

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