The Impact of Drugs & Driving and the Effect of Roadside Testing – Dr Luke Downey

Posted on: July 16, 2019
Last Updated: December 7, 2023

Associate Professor Luke Downey is an NHMRC R.D. Wright Biomedical Career Development Fellow. He leads the Drugs and Driving Research Unit at Swinburne, and specializes in human psychopharmacology with a particular interest in how individual differences in emotional intelligence contribute to human behavior. In 2015, Dr. Downey held a visiting scholar position at Harvard Medical School.

Author Quotes: 

In Victoria (Australia) more broadly, illicit drugs like cannabis, methamphetamine, MDMA are illegal drugs and if you’re caught with them in your system when you’re driving a car you can get in trouble for that, vs other types of drugs, say benzodiazepines – somewhat impairing on your driving performance as well but we don’t have as easy detection methods such as the saliva test I’ll talk about later.

Roadside alcohol testing has been around for decades now. It’s been highly effective at reducing the road toll.

Summary and slides:  

Dr. Downey gives a presentation on the effect of drugs on driving, looking at epidemiological evidence, on-road evidence, and simulator trials. He discusses the different detection methods used in different countries, and how laws are enforced. 

Looking at how drug-impaired driving is conceptualized, he compares the status in the US with that in Australia. 

He moves on to discuss the effectiveness of roadside testing in Australia and how drivers are tested using the saliva sample and breath sample. 

He highlights the economic cost behind accidents involving drugs and provides some statistics for people who have been seriously injured on Victorian roads between 2014 and 2019. 

Take-home Points: 

  • Detection of DUI in the US is broken down into 12 steps to determine the category of drugs suspected. 
  • In Australia, roadside drug testing involves a saliva test that can be analyzed in around three minutes. 
  • Saliva tests do not detect prescription drugs or common cold and flu medications. 


Learn more

  1. Drug driving: Culpability and the results from simulator trials by Dr. Luke Downey