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Drug driving  

Drug driving and the law  

In Western Australia, it is against the law for anyone to drive under the influence of a psychoactive drug or with a Blood Alcohol Concentration (BAC) of 0.05% or above. ‘L’ and ‘P’ platers must have a zero BAC when driving. 

The Road Traffic Act 1974 Section 63 states that ‘a person who drives or attempts to drive a motor vehicle while under the influence of alcohol, drugs, or alcohol and drugs to such an extent as to be incapable of having proper control of the vehicle commits an offence, and the offender may be arrested without warrant’. 

Breaking this law carries penalties including disqualification from driving, fines and/or imprisonment. 

The effects of drugs on driving  

The effects of drugs on driving ability include the following: 


  • Gives the driver a false confidence.
  • Increase risk-taking behaviour. 
  • Does not necessarily increase driving ability or the drivers coordination. 
  • Can increase the risk of having a crash. 


  • Slows the driver's reaction time. 
  • Distorts the driver's perceptions. 
  • Decreases ability to coordinate reaction when driving. 
  • Can increase the risk of having a crash. 


  • Distorts the driver's visual perceptions. 
  • Causes the driver difficulty in judging distances. 
  • Decreases ability to coordinate the appropriate reaction when driving. 
  • Can increase the risk of having a crash. 



Looking for info about the effects of a specific drug?

Check out the Drug Types page here.

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