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Drugs and drug limits

There are two testing stages in the process. First, the drug test at the roadside, which screens for four drugs. If this test is positive, a separate saliva sample is collected for laboratory analysis which tests for a total of 25 drugs and medicines.

Find out more about the testing process.

What drugs are drivers tested for at the roadside?

The first roadside drug test screens for the recent use of:

  • THC (cannabis)
  • Methamphetamine
  • MDMA (ecstasy)
  • Cocaine

The roadside drug test does not test for amphetamine or ADHD medicines. It also does not cross-react with any ADHD medicines.

A positive roadside test means that one or more of these four drugs is detected at or above the limit (threshold) built into the device (not any traces below the limit).

If this test is positive, a separate saliva sample is collected for laboratory testing.

What drugs are drivers tested for in the laboratory?

Once a saliva sample is collected and is sent to the laboratory, it is tested for the 25 drugs listed in the Land Transport Act 1998. These drugs have been identified as having the highest risk to road safety and include 21 prescription medicines and four illicit drugs.

Alprazolam

Amphetamine

Buprenorphine

Clonazepam

Cocaine

Codeine

Diazepam

Dihydrocodeine

Fentanyl

GHB

Ketamine

Lorazepam

MDMA

Methadone

Methamphetamine

Midazolam

Morphine

Nitrazepam

Oxazepam

Oxycodone

Temazepam

THC (Cannabis)

Tramadol

Triazolam

Zopiclone

 

A positive laboratory result means that a drug was detected at or above their limit (threshold) and indicates that the drug was used recently.

If a driver doesn’t test positive for cannabis, methamphetamine, MDMA, or cocaine at the roadside, they will not be required to provide a saliva sample for laboratory testing.

Drug limits (thresholds)

A limit or otherwise referred to as a threshold has been set for each of the 25 drugs in the legislation. This is the limit that each drug is tested against. Each drug threshold for saliva testing has been set after considering:

  • current scientific evidence, including drug concentrations reported in saliva and blood after recent use
  • the time period of likely impairment and
  • the length of time required to eliminate the drug from the saliva

The drug thresholds for saliva indicate that the drug has been used recently and are set to exclude past use and passive or accidental exposure. They are different than the drug limits for blood.

Find out more about how the thresholds were set.

FAQs

How soon after taking drugs can I drive?


Police cannot advise how long after taking a substance it is safe to drive. The time it takes for the effects of drugs to wear off varies by person, drug type, dose, frequency of use, and how it was taken. Drugs can slow reaction times, affect judgement, or cause drowsiness for many hours.

You can still be over the legal limit or unsafe to drive even if you feel fine. If you are unsure, don’t drive – get a lift, use public transport, ride-share, or wait.
 

Will the screening tests detect trace amounts of drugs?

 

The screening devices will not detect trace amounts if they are below the limit. The detection thresholds for each drug have been set at levels that indicate the drug was recently used, and not past use or passive or accidental exposure.