Clearing the Haze : Addressing Drug Impairment in Fleet Management
WORDS BY ANDREW LEIBE , FORENSIC TOXICOLOGIST
The following is a summary of the presentation of the same title presented at the 2024 Australasian Fleet Education & Leadership conference in May this year .
Drugs and alcohol – what are the risks ?
We are all aware of the campaigns informing drivers of the risks of driving while under the influence of Drugs or alcohol , but quantifying those risks across many different drugs is difficult given the wide spectrum of action .
Cannabis ( or marijuana ) for example , is a depressant , and so leads to effects like slower reaction times , especially complex decision making tasks in urban traffic environments . Methamphetamine ( ice , Crystal meth , speed etc ) however is a stimulant , and leads to impulsive driving decisions , extreme inattention and reduced ability to judge risk .
We can use odds ratio values however to give us some sort of guide , although there are many confounding factors involved such as fatigue , user experience with the drug etc . From the attached graph we can see the odds ratio of a driver with a BAC of 0.05 % is approx . 2 This figure climbs very steeply as the BAC increases . 1 , 2
Cannabis does not follow this pattern – any presence of the psychoactive ingredient delta-9- THC leads to a similar odds ratio of about 2 , but doesn ’ t really change even as the dose of the drug increases .
Methamphetamine , however , starts from a higher base ( approx . 5 ) and does increase with dose , making it an extremely dangerous drug to have present in a driver .
These sorts of statistics are the reason for the universal testing of Cannabis and Methamphetamine by all Australian Police forces in their random and targeted roadside testing .
How frequent is workplace drug use in Australia ?
Data collected via the Safework Laboratories Drug Testing Index during the period 2017- 2019 analysed 432,782 workplace drug tests across Australia , and across multiple industries . Approximately 45 % were urine tests and 55 % Oral Fluid ( Saliva ) tests .
Urine testing of employees via random testing or for cause / incident testing showed an overall positive rate of 7.1 % ( ie 7 out of every 100 workers randomly tested )
Amphetamines ( Speed , Meth etc ) – 2.4 % Opiates ( codeine *, Morphine ) – 1.4 % Cannabis – 2.2 %
Benzodiazepines ( sleeping tablets , tranquilizers ) & others - 1.1 %
Oral Fluid ( saliva ) testing of employees via random testing or for cause / incident testing showed an overall positive rate of 1.1 %
Amphetamines – 0.6 % Opiates – 0.3 % Cannabis – 0.2 % Benzodiazepines *, Cocaine and others - < 0.1 %
The much lower rate of detection in Oral Fluid ( saliva ) is due to the more limited time that drugs can be detected in Oral Fluid ( typically 24 hours or less ) compared to urine testing , where drugs consumed can be detected for several days post
12 ISSUE 48 AUGUST 2024 / WWW . AFMA . ORG . AU