As an OT driving assessor, I am acutely aware of the complex interplay between medical conditions, medications, and driving safety. Medicinal cannabis is a growing area of interest—and concern—especially as more people access it to manage chronic conditions. Recently, we’ve been seeing an increasing number of people being prescribed medicinal cannabis. So what’s the impact on driving?
The Queensland Government maintains a strict zero-tolerance policy regarding driving with any detectable amount of THC in the system, regardless of whether the cannabis is used medicinally. This policy applies to all drivers, including those with a valid prescription for medicinal cannabis. A positive roadside drug test can result in immediate suspension, fines, or further legal action.
Many medicinal cannabis products contain THC, the psychoactive compound that can impair driving. Research consistently shows that THC impairs critical driving functions—judgment, motor coordination, and reaction time. Multiple studies link cannabis use to increased crash risk, with some showing the risk more than doubles.
THC’s effects can vary depending on dose, frequency of use, and individual metabolism, which makes setting a “safe” limit nearly impossible. This variability is a key reason behind Queensland’s continued zero-tolerance stance. Even if prescribed for legitimate medical reasons, THC may still impair driving. Importantly, roadside tests cannot distinguish between prescribed and recreational use. This means medicinal cannabis users are subject to the same legal penalties.
Recommendations for Medicinal Cannabis Users
- Consult Healthcare Providers – Before driving, discuss with your doctor the potential effects of your medicinal cannabis treatment on your ability to drive.
- Understand Your Medication – Products containing THC can impair driving and are not exempt from drug driving laws.
- Avoid driving while using THC – Plan alternative transport options.
- Stay informed – Monitor legislative updates as reviews progress.
As a driver-trained OT, my primary concern is the safety and well-being of all road users. While medicinal cannabis plays a crucial role in managing certain health conditions, its impact on driving ability must be carefully considered. Until further research provides clearer guidelines, it is imperative that individuals using medicinal cannabis exercise caution and adhere to current laws to ensure road safety.
For more information on drug driving laws and medicinal cannabis in Queensland, visit the Queensland Government’s Transport and Motoring website.
