What is the zero tolerance policy for drugs?
The zero-tolerance policy for drug driving means that drivers face severe penalties for driving with any amount of illicit drugs, such as cannabis, ecstasy or methamphetamine, in their system. Legislation across Australian states and territories establishes offences for drug driving and provides for roadside drug testing to enforce the zero-tolerance policy in Australia.
This means that if any trace of an illicit drug is detected during a roadside drug test, you may face penalties for drug driving. It is also an offence to drive, attempt to drive or supervise a learner driver while affected by drugs.
In Victoria, unlike drink driving laws, which use breath testing to assess whether the alcohol concentration in a driver’s system is over the legal limit, a random saliva drug test focuses on detecting the mere presence of three illicit drugs—cannabis, methamphetamine, and ecstasy—in a driver’s oral fluids, regardless of the quantity or impairing effect of the drug detected.
There are a number of charges that relate to drug driving. In Victoria, drug driving offences are found under section 49 of the Road Safety Act 1986 (RSA).

Drugs and driving laws
Drug driving legislation can be complex and varies depending on the specific offence. See below for an overview of Victoria’s key drug driving charges, including the associated penalties, mandatory licence disqualification periods, and, where applicable, immediate suspension provisions.
Prescribed content drug offences
If any amount of an illicit drug is detected in your system, you could be charged with an offence under the following sections:
- s49(1)(bb) – prescribed content of a drug present whilst driving or in control of a motor vehicle
- s49(1)(h) – prescribed content of drug present in oral sample within 3 hours of driving or being in control of a motor vehicle
- s49(1)(i) – prescribed content of drug present in blood taken within 3 hours of driving or being in control of a motor vehicle.
Under section 3 of the Road Safety Act 1986, the prescribed concentration of drugs means, in the case of a prescribed illicit drug, any concentration of the drug present in the blood or oral fluid of that person.
Furthermore, “prescribed illicit drug” means—
- methylamphetamine;
- 3, 4-Methylenedioxy- N -Methylamphetamine (MDMA); or
- delta-9-tetrahydrocannabinol.
These drug driving charges have the same penalty and mandatory minimum licence disqualification periods as follows:
- 12 penalty units ($2,371.08) and a minimum of 6 months disqualification for a first offence
- 60 penalty units ($11,855.40) and a minimum of 12 months disqualification for a second offence
- 120 penalty units ($23,710.80) and a minimum of 12 months disqualification for any subsequent offence
The immediate suspension powers under section 85 of the RSA do not apply to the above offences.
It is crucial to understand that imprisonment is not a sentencing option for all the offences listed above. Shockingly, we have encountered cases where clients were wrongly sentenced to imprisonment because their lawyer failed to inform the Magistrate that imprisonment was not a sentencing option for these offences.
Don’t risk an avoidable and unjust outcome—ensure your drug driving lawyer is knowledgeable and prepared.
Driving whilst impaired by drugs
If you drive or are in control of a motor vehicle while impaired by any drugs, including prescribed medication, you could be charged with an offence under section 49(1)(ba).
The following penalties apply:
- 12 penalty units ($2,371.08) for a first offence
- 120 penalty units ($23,710.80) and 12 months imprisonment for a second offence
- 180 penalty units ($35,566.20) and 18 months imprisonment for any subsequent offence
- Licence disqualification for 12 months in relation to a first offence and a minimum of 2 years for a second or any subsequent offence.
The immediate licence suspension provisions under section 85A of the RSA apply to this offence. Accordingly, police can suspend a driver immediately once they are charged with this offence, but only at the time of charge, not at the time of the offence.
A “prescription drug”, in relation to a person, means a Schedule 4 poison or Schedule 8 poison within the meaning of the Drugs, Poisons and Controlled Substances Act 1981, which that person is authorised or under that Act to have in their possession (s3 RSA).
How a saliva drug test works
In Victoria, roadside drug testing involves a preliminary and a secondary oral fluid test using two different devices. The officer takes a saliva sample by placing an absorbent collector in the mouth or tongue for a few seconds, which is analysed at the roadside.
The driver is asked to undertake a secondary roadside test if the preliminary test produces a positive result. The sample is sent to a laboratory for confirmation if the secondary test is positive. A confirmed positive result will likely lead to a drug-driving charge.
A positive saliva drug test result indicates the presence of one of three illicit drugs in the body (i.e. cannabis, ecstasy or methamphetamine), regardless of whether the driver is impaired, and it is the reason why drivers can be charged after the effects of a drug have ceased.
If police believe the driver is affected by a drug other than those detected in an oral fluid test, even prescription medications, they may request the driver to undergo a drug impairment assessment and blood or urine test. A blood or urine analysis can detect a wide range of substances and specific concentrations.
Can you drive after taking any prescription medication?
You should not drive after taking any prescription medication that can impair your driving ability. It’s illegal to drive while impaired by any drug, whether a doctor prescribes it or it is an over-the-counter medication.
Certain medications can significantly impact your ability to drive safely by affecting your concentration, mood, coordination, and reaction times. When combined with alcohol, these effects can further impair your ability to drive safely.
Medicines may impair driving by causing dizziness, drowsiness, nausea, blurred vision, slow reaction times, inability to focus, sleepiness, confusion or feeling overconfident.
Examples of medications that may affect driving include:
- Benzodiazepines
- Antidepressants
- Antipsychotics
- Cannabinoids
- Antihistamines
Other medications for the treatment of blood pressure, nausea, allergies, inflammation and fungal infections can also impact driving.
Drivers should always read medication labels, consider warnings about drowsiness or impaired alertness, and consult healthcare professionals if unsure about a medication’s impact on driving.
Speak to your doctor or pharmacist if your medication is likely to affect your driving. This is especially critical if you are starting any new medication, which may have an impairing effect as you adjust to it, even if there is no specific warning associated with it.
If there is a chance that your driving might be impaired by medication, take public transport or a taxi, or ask a friend or relative to drive to avoid the risks.
Defence for permissible prescription medication
If a person charged with an offence under section 49(1)(ba) was found to have had only a permissible prescription drug present in their body, it is a defence if they did not know and could not reasonably have known that the drug would impair driving if consumed in accordance with relevant health practitioner advice.
Medicinal cannabis driving Victoria
Currently, the zero-tolerance policy to THC (cannabis) in drivers’ systems does not differentiate between impairment and the mere presence of the substance.
This means that medicinal cannabis patients who drive, even when not impaired, can face mandatory license suspensions and fines if even only a minute trace of THC is found during random roadside drug testing.
However, soon, drivers who use medicinal cannabis and who test positive for drugs in a random roadside saliva drug test may no longer automatically lose their driver’s licence.
Victoria’s Legislative Council has recently passed an amendment in the Road Safety Amendment (Medicinal Cannabis) Bill 2023 to allow Magistrates to use discretion when sentencing drug driving offences for those driving with cannabis in their system who have a valid prescription and who were not impaired at the time of the offence.
Clause 3 of the Bill provides that certain offences in section 49(1) do not apply to a person whose blood or oral fluid contains delta-9-tetrahydrocannabinol from a cannabis product consumed lawfully, so long as that product is medicinal cannabis for which the person has a prescription or other authority and the medicinal cannabis has been consumed in accordance with that prescription or authority.
Importantly, the bill does not affect the application of offences in section 49(1)(a) and (ba) to persons who are incapable of having proper control of a motor vehicle or impaired by a drug while driving a motor vehicle.
This means it will remain an offence for a person impaired by medicinal cannabis (or any other prescription medication) to have control of a motor vehicle.
ADHD medication
An initial saliva test will not detect the presence of prescription drugs, including those medicines containing amphetamine-like substances, such as dexamphetamine (used to treat ADHD).
ADHD medication such as dexamphetamine alone should not produce a positive result on an initial roadside drug test as it is not the same as methamphetamine. However, a person who produces an initial positive saliva or oral fluid test is required to provide a second saliva sample for a much more accurate laboratory test.
Know Your Rights
Drug driving laws in Victoria enforce a strict zero-tolerance policy, with serious penalties for those caught with drugs in their system, regardless of impairment. These laws are designed to improve road safety, but they can be complex and carry severe consequences.
If you’ve been charged with driving with drugs in your system, it’s essential to understand your legal rights and options. Contact an experienced drug driving lawyer to ensure you receive expert advice and representation tailored to your situation.