(NSW) Exempt Prescribed Medical Cannabis Users from THC Driving Offences while Unimpaired

Author: Pierre-Louis Rossi | Publish date: 18/06/2024

Problem Identification: 

In NSW, individuals who are legally prescribed medical cannabis can be charged if delta-9-tetrahydrocannabinol (THC) is detected in their system while driving.

Under Schedule 1 of the Drug Misuse and Trafficking Act 1985 (NSW), THC is classified as a prohibited drug. Section 111 of the Road Transport Act 2013 (NSW) establishes that driving a motor vehicle with any detectable amount of an illicit drug in one’s system constitutes an offence. NSW Health has confirmed that there is currently ‘no medical defence to these offences for using a prescribed cannabis medicine.’

This means that if a driver undergoes Mobile Drug Testing (MDT) and tests positive for THC (independent of the level of driver impairment or if it was medically prescribed), they can be charged. This can include automatic license suspensions and heavy fines.

Context: 

A medical defence refers to a legal protection that drivers can use after testing positive during an MDT. Medical defences may allow individuals to avoid conviction if they can prove the substance was legally prescribed and taken according to their medical practitioner’s instructions.

Medicinal cannabis refers to cannabis-based products prescribed by a registered healthcare professional. The Therapeutic Goods Administration has noted that these products are commonly prescribed to treat long-term conditions such as chronic pain, multiple sclerosis, cancer-related symptoms and chemotherapy-induced nausea. According to the University of Sydney’s Lambert Initiative for Cannabinoid Therapeutics, medicinal cannabis is broadly classified into 2 categories: THC-dominant and cannabidiol-dominant (CBD) products, depending on which compound is more prevalent. 70% of prescribed products contain THC, the main psychoactive component in cannabis. THC is one of the substances tested for during MDT in NSW. According to Drive Change, between 2019 and 2023, police conducted 677,494 such tests. However, according to the NSW government’s Centre for Medicinal Cannabis Research and Innovation, patients prescribed CBD cannabis products may still legally drive, provided they are not impaired. 

According to the Burnet Institute, there is a legal inconsistency where the historical classification of cannabis as a prohibited drug overrides current medical use and safety evidence. Research from the Lambert Initiative has indicated that the impairing effects of THC last between 3 to 10 hours. However, the Alcohol and Drug Foundation has highlighted that THC remains detectable for up to 12–30 hours after use. Thus, drivers may test positive, well after THC-induced impairment has passed. The Lambert Initiative has concurred and stated that, unlike a driver’s blood alcohol level tested for during a Random Breath Test, THC biomarkers are not a reliable guide to impairment. They have argued that roadside tests for the presence of THC ‘are relatively poor or inconsistent indicators of THC-induced impairment.’ Drive Change has further argued that, unlike alcohol and other prescription medications, which are known to impair driving (in some cases more than THC), THC use attracts automatic penalties based on presence alone. Drive Change has reported that Australia is the only country to criminalise the presence of THC alone.

The absence of a medical defence provision has been reported to especially affect patients in rural and regional areas, where driving can be essential for daily life and healthcare access. As Professor David Heilpern has noted, these laws can lead to serious hardship and isolation by forcing patients to choose between mobility and following medical advice.

The 2024 NSW Drug Health Summit report has recommended legislating ‘for a medical defence for people using medically prescribed cannabis who are driving.’ They have said that this could balance road safety and the rights of patients who are legally prescribed cannabis to drive their vehicles. The Lambert Initiative’s Academic Director, Ian McGregor, has stated: ‘Laws should be about safety on the roads, not arbitrary punishment. Given that cannabis is legal in an increasing number of jurisdictions, we need an evidence-based approach to drug-driving laws.’

There is domestic precedent for instituting a medical defence for the presence of THC when driving. In TAS, the presence of THC is not an offence if the substance was legally prescribed and taken according to a practitioner’s directions. Further, in NSW, there is already a medical defence in the Road Transport Act 2013 (NSW), where drivers can defend a positive result for morphine if the substance was taken for ‘medicinal purposes.’

Solution Identification: 

Amend section 111 of the Road Transport Act 2013 (NSW) to introduce an exception if the THC detected was prescribed by a registered healthcare professional in NSW or another Australian state or territory, provided the driver was taking their medication in line with their practitioner’s instructions.

This could allow NSW drivers with valid THC prescriptions to drive and use their medication as directed, without fear of being penalised.

Advice:

The NSW Minister for Roads should amend the Road Transport Act 2013 (NSW) as specified above at the next opportunity.

Download the 1-Page Brief Here - (NSW) Exempt Prescribed Medical Cannabis Users from THC D.

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Public Support: 

1. NSW Health 

2. Drive Change

3. Lambert Initiative for Cannabinoid Therapeutics

4. Burnet Institute

Where to go to learn more: 

1. Drive Change - Their report focused on roadside drug testing laws and their campaign for a medical defence for prescribed cannabis patients. View their 2025 report on roadside policing for cannabis here.

2. NSW Health Drug Summit Report 2024 - Served as the key policy foundation for this brief. Priority Action 10 of the report explicitly recommended legislating a medical defence for prescribed cannabis users who tested positive for THC. Read the full report here.

3. Lambert Initiative for Cannabinoid Therapeutics - A research centre based at the University of Sydney, whose findings on THC impairment, detection windows, and drug-driving law directly informed the evidence base for the proposed defence. Read about their research here.

4. Burnet Institute - An Australian medical research institute whose work criticised current roadside drug testing policies. Their research article discussed how THC presence-based laws may not align with road safety goals. Read it here.

5. Penington Institute Cannabis in Australia 2024 - Offered legal and policy context, including commentary on inconsistencies between cannabis laws and drug-driving penalties. Helped position the brief within a broader national policy conversation. View here.

6. NSW Health Factsheet on Prescribed Cannabis and the Fitness to Drive - Confirmed that there is currently no medical defence for prescribed THC in NSW and outlined how current drug-driving laws apply to patients. View here.

7. NSW Centre for Road Safety, Drugs & Driving - Provided an overview of NSW drug-driving laws, enforcement practices, and the role of Mobile Drug Testing. View here.

8. Road Transport Act 2013 (NSW) - The Act, which this brief proposes to modify. Section 111 established the offence of driving with an illicit drug in one’s system, which included THC. Read the full act here.

Human Perspective:

John, a 57-year-old farmer from rural Dubbo, was prescribed medicinal cannabis to manage chronic back pain after decades of physical labour. With no public transport in his area and the nearest GP 45 minutes away, driving is essential to access basic services and care for his property. Despite never driving while impaired, John tested positive for THC during a routine roadside check and lost his license, cutting him off from medical appointments, farming supplies, and his only source of income. This sudden loss of mobility left him feeling isolated, anxious and increasingly withdrawn, compounding the very health challenges his medication was meant to manage.. To protect the anonymity of those involved, this is a fictionalised account drawn from an amalgamation of real-life stories, experiences, and testimonials gathered during the research process for this brief. Any resemblance to actual individuals is purely coincidental.

Conflict of interest/acknowledgment statement: 

N/a

Support 

If your organisation would like to add your support to this paper or suggest amendments, please email Info@foreaustralia.com. 

Reference list: 

Alcohol and Drug Foundation. (2024, January 16). Roadside drug testing. https://adf.org.au/insights/roadside-drug-testing/

Centre for Medicinal Cannabis and Driving. (2022, December). Cannabis medicines and driving: Fact sheet. NSW Health. https://www.medicinalcannabis.nsw.gov.au/__data/assets/pdf_file/0025/2869/Fact-sheet-Cannabis-medicines-and-driving-December-2022.pdf

Centre for Medicinal Cannabis and Driving. Driving. NSW Health. https://www.medicinalcannabis.nsw.gov.au/patients/driving

Department of Health. Medicinal cannabis information for patients and the general public. Tasmanian Government. https://www.health.tas.gov.au/health-topics/medicines-and-poisons-regulation/medicinal-cannabis/medicinal-cannabis-information-patients-and-general-public

Drive Change. (2025, February). Reform for roadside drug testing in New South Wales. https://www.harmreductionaustralia.org.au/wp-content/uploads/2025/02/Drive-Change-NSW-REPORT-Final-19.2.25.pdf

Healthdirect Australia. Medicinal cannabis. https://www.healthdirect.gov.au/medicinal-cannabis

Lambert Initiative for Cannabinoid Therapeutics. (2021, April 12). Scientists put the stopwatch on cannabis intoxication. The University of Sydney. https://www.sydney.edu.au/news-opinion/news/2021/04/12/scientists-put-stopwatch-on-cannabis-thc-intoxication-lambert-drug-driving.html

Lambert Initiative for Cannabinoid Therapeutics. (2021, December 2). THC in blood and saliva are poor measures of cannabis impairment. The University of Sydney. https://www.sydney.edu.au/news-opinion/news/2021/12/02/thc-blood-saliva-poor-measures-cannabis-impairment-lambert-study.html

Lambert Initiative for Cannabinoid Therapeutics. What products are available? The University of Sydney. https://www.sydney.edu.au/lambert/how-to-get-medicinal-cannabis/what-products-are-available.html

McCartney, D, Arkell, T. R., Irwin, C, Kevin, R. C., & McGregor, I. S. (2022). Are blood and oral fluid Δ9-tetrahydrocannabinol (THC) and metabolite concentrations related to impairment? A meta-regression analysis. Neuroscience & Biobehavioral Reviews, 134, 1–10. https://doi.org/10.1016/j.neubiorev.2021.11.004

NSW Government. Drug Misuse and Trafficking Act 1985 No 226. https://legislation.nsw.gov.au/view/whole/html/inforce/current/act-1985-226

NSW Government. Road Transport Act 2013 No 18. https://legislation.nsw.gov.au/view/html/inforce/current/act-2013-018#sec.111

NSW Health. (2025, April). Report on the 2024 NSW Drug Summit. https://www.health.nsw.gov.au/aod/summit/Documents/2024-nsw-drug-summit-report.pdf

Perkins, D., et al. (2021). Medicinal cannabis and driving: The intersection of health and road safety policy. Burnet Institute published in the International Journal of Drug Policy, 97. https://doi.org/10.1016/j.drugpo.2021.103307

Southern Cross University. (2025, 3 February). Experts call for reforms to medicinal cannabis roadside testing. https://www.scu.edu.au/news/2025/experts-call-for-reforms-to-medicinal-cannabis-roadside-testing/

Therapeutic Goods Administration. (2024, November 28). Guidance for the use of medicinal cannabis in Australia: Patient information (Version  https://www.tga.gov.au/products/unapproved-therapeutic-goods/medicinal-cannabis-hub/medicinal-cannabis-guidance-documents/guidance-use-medicinal-cannabis-australia-patient-information

Transport for NSW. Drugs and driving. NSW Government https://www.transport.nsw.gov.au/roadsafety/topics-tips/drugs