Drugs and driving - get the facts

Legal prescription, over-the-counter medications and illegal drugs can affect your ability to drive safely.

Drug driving is dangerous. Drugs can affect your judgement, vision, coordination and reflexes – all of which increase your risk of having a crash.

The facts

  • Police may require a driver to provide a specimen of saliva for analysis.
  • Roadside drug tests detect the presence of methamphetamine (also known as speed and ice), MDMA (the active ingredient in ecstasy) and THC (the active ingredient in cannabis).
  • There is a zero tolerance in Queensland for drug driving.
  • If a police officer suspects your ability to drive has been impaired by any drug, you can also be required to provide a specimen of blood for analysis.

Risky behaviour

A 2020 survey of 3,000 Queensland drivers found that1 5% of the Queensland drivers surveyed reported driving when they had taken illegal drugs. While a minority of drivers report drug driving, the National Road Safety Strategy 2011-20202 identified drug driving as a contributing factor in 7% of serious casualty crashes nationally.

Most states have introduced roadside drug testing programs. In Queensland, in 2018/2019, almost 70,000 roadside drug tests were conducted resulting in approximately one in five drivers (20%) testing positive for a relevant drug3. Drivers who test positive have their licence suspended for 24 hours to allow drugs to dissipate from their system.

The effects of drugs on driving

The effects of drugs on driving vary depending on the type of drug.

Drugs can affect your driving by causing:
  • reduced ability to judge distance and speed
  • distorted time, place and space
  • reduced coordination
  • hyperactivity
  • aggressiveness
  • paranoia
  • hallucinations
  • blurred vision
  • convulsions
  • dizziness and fainting
  • fatigue
  • memory loss
  • nausea
  • tremors
  • mood swings
  • unconsciousness
  • muscle weakness.
When taking prescription and over-the-counter medications, you should consult with your doctor or pharmacist to discuss:
  • any adverse effects you may be experiencing when taking medications
  • any changes to the dosage or new medications you may be taking
  • warning labels or potential effects of any medication you are taking on your ability to drive safely (as well as safety associated with other common activities)
  • combined or cumulative effects of any other medications you are taking at the same time (e.g. you may be fine to drive when taking one medication or another, but not when you take both)
  • effects of alcohol when taking medications
  • how to use and store your medication
  • what to do if you miss a dose of your medication
  • when it is appropriate to stop taking your medication.

If you are unsure how drugs may affect your driving, think about asking someone for a lift, catch public transport or arrange a taxi or booked hire service. This will allow you to monitor the effects the drugs are having on your system.

Myth busters

"Roadside drug testing will only detect drugs taken within a few hours."

The saliva tests are designed to only react with the active ingredient of the relevant drug.

The detection period for the active ingredient in the relevant drug varies depending on factors such as the quantity and quality of the drug that has been ingested, the frequency of use of the drug and the period of time since taking the drug.

"I will know if it’s not safe for me to drive."

Mixing drugs and driving can be just as dangerous as drink driving. Drugs affect each person differently and some people may not even be aware of the affects a drug is having on them, until it’s too late. Factors such as the quality and quantity of the drug taken, frequency of use, or mixing with other drugs or alcohol, all influence the effect a drug will have at any given time.

Remember that conditions can change very quickly when you’re driving and being able to respond quickly is vital to keeping both yourself and other road users safe.

Tips for keeping safe

Mixing drugs with other drugs or alcohol can seriously affect your health and your ability to drive safely.

  • Never drive after taking illegal drugs.
  • Never drive after taking prescribed or over-the-counter medications that could affect your driving.
  • If you take a prescription or illegal drug and you are unsure of the effect of that drug on your ability to drive, don’t drive, use public transport, ask someone else to drive or catch a taxi.

Get the right advice

You should always check with your doctor or pharmacist if it is safe to mix your medications or to drink alcohol while on your medication and how the drugs you are taking can affect your driving. Always follow the recommended dose, read the information and warning messages provided on the container or information provided with your medication, and never take someone else’s medication.

For more information

For confidential help and/or information contact the Alcohol and Drug Information Service on (07) 3837 5989 (all hours) or 1800 177 833 (toll free). The statements contained in this fact sheet are for information purposes only and should not be used for any other purpose.

  1. Footprints Market Research (2020). Department of Transport and Main Roads Driver Attitudes & Behaviour State-wide Research.
  2. Australian Transport Council, National Road Safety Strategy 2011-2020, 20 May 2011.
  3. Queensland Police Service (2019). The State of Queensland, Queensland Police Service Annual Report 2018-19. Retrieved 12/08/2020.

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