Centre for Road Safety

Taking illegal drugs before driving puts you at greater risk of injuring or killing yourself, your friends or other innocent people. Our research shows that the presence of illegal drugs is involved in around the same number of fatal crashes as drink driving.

Effects of illicit drugs on driving

Safe driving requires good judgement and sharp concentration. You also need to react quickly to changing situations on the road. The use of illicit drugs causes changes in the brain which can impair driving ability and increase crash risk.

The effects of drug use depend on the type and concentration of the drug taken and vary widely between individuals. In the case of illicit drugs, the exact chemical substance, dosage and duration of the effects can be difficult for users to estimate.

Mobile Drug Testing

The NSW Government takes a zero tolerance approach to drug driving, to stop drivers putting themselves and others at risk by getting behind the wheel after using drugs.

Mobile Drug Testing (MDT) detects the presence of four common illegal drugs: ecstasy, cannabis, cocaine and methamphetamine (including speed and ice). MDT can be conducted at roadside operations along with random breath testing (RBT), or by NSW Police in vehicles patrolling our roads. MDT has been increasing and by the end of 2020 police will have doubled the number of roadside drug tests to 200,000 per year.

How MDT works

As with RBT, you will be stopped by police, asked for your licence, and complete a breath test for alcohol. Following this, the procedure for MDT is:

  • You will be asked to wipe a MDT test stick down your tongue to check if you have illegal drugs in your system.
  • The results take a few minutes to appear and you must wait until police say you are in the clear. Most drivers test negative and are soon on the road again.
  • If your MDT test is positive, you’ll be taken to a roadside testing van or bus, or back to a police station to provide a saliva sample.
  • This sample will also be tested and if positive, you’ll be banned from driving for 24 hours. All samples are sent to a laboratory for analysis. If confirmed positive tough penalties apply.

Driving under the influence of drugs

You can also be charged with Driving under the Influence (DUI) of illegal or prescription drugs, if you are driving while affected by a drug. Drugs are detected through blood and urine tests which are ordered if a police officer has reasonable suspicion that a driver is under the influence of a drug or drugs.

The penalties for a DUI offence are higher than for a presence offence (detected by MDT). All drivers involved in fatal crashes in NSW undergo blood and urine testing for drugs and alcohol.


Drug driving is a serious offence. It is also an offence if you refuse to take a drug test. Penalties can include loss of licence, fines and prison terms.

As part of the Road Safety Plan 2021, changes came into effect on 20 May 2019 to simplify and improve the certainty of penalties for first-time offences for driving with the presence of an illegal drug, which are typically detected through MDT.

If your roadside positive result is confirmed by the laboratory and it is a first-time offence, you may receive a fine and your licence will subsequently be suspended for three months. If it is a second or subsequent offence you will need to go to court and may receive a licence disqualification and fine.

If you are found guilty of driving under the influence, even higher penalties apply.

Combined drink and drug driving offence

Since 28 June 2021 a new law introduced harsher penalties for combined drink and drug driving offences.

Tougher penalties apply for a combined offence, compared to those currently available for separate drink and illicit drug driving offences.

The offence is designed to deter this high risk behaviour and send a clear message to drivers that they are putting themselves and others at significant risk when mixing alcohol and drugs with driving and this behaviour will not be tolerated on NSW roads.

Don't take the risk

Illegal drugs can be detected in your saliva by an MDT for a significant time after drug use, even if you feel you are OK to drive. The detection period varies depending on the type of drug, amount taken, frequency of drug use, and other factors that vary between individuals.

If you think that you may have illegal drugs in your system, the best decision is not to drive.

  • Our Getting home safely tips have advice on how to avoid the risk of driving if you have used drugs.
  • The Stop it... Or cop it campaign reminds drivers that mobile drug testing can occur anytime, anywhere and the next police car you see could stop you for MDT.

Our Mobile Drug Testing TV advertisement warns drivers that NSW Police can test them for drugs anytime or anywhere, there's no escaping it. Read a transcript.