Drug-driving law takes effect Sunday Nov 1st
Date: Tuesday, October 27 2009
Topic: Laws


A new testing regime takes effect from 1st November 2009 that will let police officers test drivers for impairment caused by illegal drugs.

Police will first perform a standard breath test, and if the driver passes that but appears impaired, the officer can then require the driver to perform a Field Sobriety Test (standing on one leg, etc). If the officer then believes the driver has failed that test, they can compel a blood test. Any traces of cannabis residue, which for regular users can permanently stay in the blood, will be enough for conviction, whether or not it is enough for impairment.

NORML advocates "responsible cannabis use", and believes driving to the point of impairment is not responsible and should remain illegal even when cannabis use is legalised. However NORML has several concerns with the new driver testing regime:

The opinion whether a person "appears" impaired, or whether they have failed the Field Sobriety Test, and must therefore give a blood sample, is up to individual police officers.

Lots of people can't balance on one leg, but that doesn't mean they are impaired. Deciding whether a driver has passed or failed the test will be an entirely subjective opinion.

NORML's experience has been that Police tend to pick those who fit the stereotype of a "stoner". This law will mean any police officer could just say they were impaired, and force them to give a blood sample. This law could simply become yet another tool to harass those the police believe use cannabis, rather than being about making the roads safer.

Drug tests should measure THC, the active ingredient in cannabis, and not it's non-active metabolites that stay in the body for weeks.

NORML is pleased the Government listened to our concerns, and will limit the blood test to measuring only THC.

However rather than any trace residue being enough for a conviction, there should be a THC level that corresponds to the legal Blood Alcohol Concentration.

This is because, despite the false assurances of NZ officials, THC stays in the blood for several days after stopping use, especially for chronic, heavy, users. A drug-driving law that sets a zero-tolerance for THC, such as like we now have in New Zealand, will therefore result in the wrongful arrest and conviction of drivers simply because they have residual traces of THC in their blood, rather than them being actually impaired while driving.

European researchers led by F. Grotenhermen found "serum concentrations of THC below 10 ng/ml are not associated with an elevated accident risk" and recommended setting a permissible blood THC level of 7-10ng/ml to be consistent with the European alcohol limit of 0.5 (NZ's drink-driving law allows 0.8).

NORML is extremely concerned that a positive test could be used to harass and search people, and/or prosecute them for using cannabis.

More than half the adult population have used cannabis, and the vast majority do so moderately and responsibly. Police could target anyone they don't like, with a fairly good chance they will test positive.

Police could use this law to harass people who appear to fit the stereotype, or who have brown skin. It will be an easy way for police to circumvent the Bill of Rights.

As a result, this law could encourage some people to switch to more risky drugs which do not linger in the body, such as alcohol, opiates or methamphetamine.

According to the NZ Ministry of Transport, the Field Sobriety Test includes:

* an eye assessment – pupil size, reaction to light, lack of convergence, nystagmus (ie abnormal eye movement - irregular eye movement can be a marker for drug impairment)
* a walk and turn assessment
* a one leg stand assessment.

"It is based on a test used in the UK and adapted for the New Zealand Police by experts from Swinburne University of Technology, Melbourne. Details of the test will be published in the New Zealand Government Gazette," they said.

More information:

  • NORML's Principles of Responsible Cannabis Use
  • NORML USA driver drug testing information
  • Marijuana and Driving: A Review of the Scientific Evidence
  • F Grotenhermen, et al: Developing limits for driving under cannabis, Addiction, 2007.
  • California NORML: Drug test detection times
  • NZ Herald 28/10/2009: Police ready for tests on suspected stoned drivers
  • NZ Ministry of Transport: Questions and answers on new law to combat drug impaired driving






  • This article comes from NORML New Zealand: working for marijuana law reform
    http://norml.org.nz

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