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Drug driver testing – Expert Reaction

The Government is seeking public feedback on how drug driver testing can improve road safety.

Drug testing behind the wheel isn’t as simple as it is for alcohol because the current drug tests can only detect the presence of drugs or medication – not whether a driver is impaired by a drug.

Minister of Police Stuart Nash says: “irrespective of whether someone is impaired by alcohol, medication or recreational drugs, they shouldn’t be behind the wheel”.

The accompanying discussion document contains data on the number of drug and alcohol-related fatal crashes. Analysis by ESR forensic scientists of the blood samples of drivers killed in crashes between January 2014 and May 2018 shows 29 per cent had used alcohol, 27 per cent had used cannabis, 10 per cent had used methamphetamine, and 15 per cent had used other drugs.

The Government is looking for feedback on:

  • the methods that could be used to screen and test for drugs
  • the circumstances in which a driver should be tested
  • what drugs should be tested for
  • how an offence for drug driving should be dealt with by police.

The SMC asked experts to comment. 

Dr Fiona Hutton, Senior Lecturer, School of Social and Cultural Studies, Victoria University of Wellington, comments:

“It is excellent to see that there is a focus on impairment rather than simply detecting drugs in a person’s system, as there are problems with the concept of ‘impaired’, particularly in relation to drugs like cannabis which stay in people’s system for a long time. Are people impaired or have they just smoked a joint two weeks ago?

“If someone smokes cannabis on a Saturday night and tests positive on a Monday morning they will have cannabis in their system but not be impaired – similar to if someone drank a glass of wine or had a bottle of beer on a Saturday night, they would not be impaired on a Monday morning.

“Any impairment that affects people’s driving and has the potential to cause accidents is a cause for concern.

“Roadside testing must not fall into the trap that workplace testing has, and make sure that drivers who are drug tested at the roadside are actually those who are impaired. However, drug impaired driving is already happening. Many prescription medicines, particularly opiate based ones like tramadol (also sedative antidepressants, antipsychotics, antihistamine, and some antiepileptic medicines) impair people’s driving, so drug driving is occurring on many levels in New Zealand (as well as in other countries).

“It is also excellent to see public consultation on this issue as well as a focus on reducing the harm from drivers who are impaired by alcohol and other drug use.”

No conflict of interest.