Answering Cannabis Law FAQ

With cannabis available via a prescription in Australia since 2016, both doctors and patients are increasingly more likely to consider it as part of a healthcare practice.

Medicinal cannabis is already widely prescribed for conditions including PTSD, chronic pain, anxiety, and insomnia. Although the health industry generally agrees with its medicinal merits, the driving laws still classify cannabis as a criminal substance.

Campaigns like Drive Change exist during this transition phase to help shape what drug driving laws will eventually look like.

Mat Henderson

This brings a lot of questions into view for patients who are prescribed medicinal cannabis, those who are interested in it, and the doctors who prescribe it. Some of the most persistent and important questions surround exactly how legal medicinal cannabis fits into the framework of current drug driving laws.

This was the focus of our first webinar, an Ask Me Anything-style event titled Ending Discrimination: Medicinal Cannabis & Drug Driving Questions Answered. With a panel of experts and a community of supporters, the conversation revealed a lot of confusion around medicinal cannabis’ legal standing on the roads.

These common questions give some insight into how the laws work currently, and how we plan to see them change.

Here’s a list of the questions in case you want to jump ahead:

Measuring THC Impairment

Q: Why won’t politicians accept the science regarding THC and impairment, as they did for drink driving?

A: There are several reasons, most of which are residuals of the War on Drugs. Police are resistant to change roadside THC detection procedure. Even if they would consider it, there is currently no way to accurately measure someone’s impairment on THC as we can with alcohol.

There is also the pharmaceutical industry and lobbyists to consider. Big Pharma is king, and revisiting drug driving protocol would inherently mean putting benzo/opioids under the same microscope–something that no one wants to do for fear of ruffling feathers. Unless a corporation is willing to put the science of medicinal cannabis in front of legislators, it will likely remain under the radar. -Mat Henderson

Q: How developed are technologies to test for impairment? Are there any examples of such technologies used overseas? Are there better ways to test for impairment rather than RDTs?

A: Yes, we had an interesting session with the creator of DRUID. Check it out.

Cannabis Patients Rights and Limitations

Q: Why can’t patients be given a medical card and/or use relevant TGA approvals to protect them at RDT?

A: It should be possible, but first we would need a change in the law. And that’s what we are striving for. –David Heilpern

Q: Are there documents or laws we can cite that will protect those of us that use this medicine responsibly?

A: Sadly, no. Mere presence without impairment is still presence and that’s all that matters under existing laws. – Mat Henderson

Q: Can TGA create a database of current patients for police, or would this be a breach of privacy and information?

A: It would be easy to set up with the patients permission, but can only happen if the law changes. -David Heilpern

Q: Do you think it’s possible that we will see a National approach to driving laws and driving law reform anytime soon?

A: Within the next ten years or not at all. – Mat Henderson

Q: Is there any legal standing for patients to deny a RDT?

A: Like Random Breath Testing (RBT) for alcohol, you can be charged as if you failed the RDT if you deny taking one. -David Heilpern

Q: How long does a drug driving suspension apply?

Suspensions vary from state to state. You can check your local guidelines here

Policing Medicinal Cannabis

Q: Why does the law target THC when there are so many other legal or illegal substances which cause worse impairment?

A: Simply because of the historical hangover from the War on Drugs where THC was primarily associated with recreational cannabis. This association still exists. We are living through a transitional era where the law will eventually align with the new reality that THC is also a prescribed medication. Precisely what that regime eventually looks like is anyone’s guess, but campaigns like Drive Change exist during this transition phase to help shape what those laws will eventually look like. – Mat Henderson

Q: Is it fit and proper for police to be advocating for the law and to determine public policy on health outcomes?

A: There is no problem with the police union speaking out, or the police minister. That is their role and function. However, police are meant to apply the law, not comment on it. It is our opinion that these comments ought not be aired in public. What politician would have the guts to go against the police? The police know this, and use their power. It is wrong. -David Heilpern

Q: Why do the police have vested interests in keeping these current laws and how can we better educate them?

A: The police in NSW get a budget allocation directly from Road Safety to administer the tests, thus the police have a vested interest. -David Heilpern

How to Help Drive Change

Sign the petition, which helps us to prove to lawmakers how much support is in favour of drug driving law reform.

You can also help support the ongoing cause by donating to Drive Change.

Dr Teresa Towpik: “Ignorance Isn’t Bliss, Knowledge Is.”

Read time: 4 minutes

This article is written by Drive Change ambassador Dr. Teresa Towpik. Below, she shares her experience with the drug driving laws from the standpoint of a medicinal cannabis doctor and patient.

January 2016–what a month it was for me. 

I didn’t realise it then, but this would mark the beginning of a new chapter in my life. This was when I first heard that cannabis was going to be legalised for medicinal use. 

At the time, I was extremely surprised. I didn’t even really understand cannabis. To me it was better known as marijuana, a drug of addiction; dangerous and to be avoided. 

However, once I started to do my research, I realised how wrong and ignorant I had been. 

It soon became clear to me that I was now dealing with an amazing herb that has incredible medicinal and healing properties. I felt touched and inspired by patients’ stories, especially children suffering from intractable epilepsy. I began to see cannabis as a sophisticated plant.

In learning all this, I discovered that I wasn’t able to be passive and conveniently wait for others to speak up about this. I decided to become an advocate of cannabis and committed to long hours learning about this plant. 

Real-World Use

I made the decision to become involved in prescribing cannabis as a doctor. It was a difficult process to begin, because the access to cannabis was cumbersome and convoluted. It required hours of paperwork that turned into countless rejections from both TGA and NSW Health State Department. 

I first applied to the TGA when I had a patient who suffered from Parkinson’s disease. The application to prescribe was approved by the TGA in September 2017, but NSW Health kept rejecting it. There was a lot of back and forth, even a solicitor was involved.

Finally, in March 2018, I got my approval. It seemed the floodgates were open, and after that every application was approved within 48 hours.

Since then, I have prescribed cannabis for many patients and have observed how it changed them for the better. Many of my patients became more functional, alert, and active. A few of them even said to me “my brain is not so foggy anymore.” 

I have seen firsthand the positive effects cannabis has on these patients. For many of them, cannabis offers a return to normalcy, reinvigorating their functionality, motivation, and inspiration in life. It’s the key for them to return to working jobs, socialising, and living a full life.

Cannabis and Road Safety

Unfortunately, there is a very significant roadblock to improving patient outcomes through prescribing medicinal cannabis in Australia. That roadblock is the discriminatory and unfair drug driving laws on medicinal cannabis patients.

These laws are causing significant harm to many people dealing with pain and illness in our society. Many of these are people who have exhausted various therapeutic options in treating their condition with no success. Eventually, they come to think and feel that they are forgotten by the health system.  

Medicinal cannabis makes it possible for patients to leave behind days of taking 10-20 different medications, many of which reportedly makes them feel like zombies.

Some patients said that there were instances where they wouldn’t even remember how they managed to get from point A to B when driving on conventional prescription medicine.

I have had many patients comment that they became better drivers while taking cannabis. As a doctor I had to ask myself: what do I do in this situation? Should these people be reported for breaking the law?

Doctor, Advocate, Cannabis Patient

Through my professional experience I can tell you that the current drug driving laws limit clinical decisions. For many practitioners, the choice is often based not on what patients need, but on what the driving laws allow. Unfortunately, the laws don’t quite make sense. 

Roadside tests currently screen for THC in the system as defined by a mouth swab. Any amount present is considered a criminal act. However, there is clear scientific evidence which proves the level of THC in the system does not correspond with impairment. If it did, I might be classified as a criminal myself.

medicinal cannabis is a legal way to treat many illnesses.

In 2001, I was diagnosed with metastatic breast cancer. In May 2019, we discovered it was recurrent.

To cope with the effects of my cancer treatment, I have been taking significant doses of cannabis for the past 2 years. When I am not impaired, I have been driving. It is extremely unfair to know that the system labels me a criminal in this situation.

I am aware of the law’s zero-tolerance for THC, even for medicinal cannabis patients, but the fact is that I need my car to function. This is a situation that many patients experience in their lives, and no one is exempt from roadside drug testing.

I was drug tested on my way to Nimbin on 2 May of this year. Aware that this was a risk, I skipped my cannabis medication for 2 days before my trip. Still, my heart sank when I was stopped by the police. A lot went through my head, all the possibilities and consequences of me possibly testing positive. The fact that I have to deal with living in fear of being penalised for dealing with my condition feels terrible.

We know that cannabis is fat soluble and can stay detectable in the system much longer. Luckily, I tested negative. For me the trace amounts of THC was gone in two days, but this time frame varies by person, in part due to the rate of metabolism. I was not impaired and my driving record remains in good standing, but many patients feel like they are constantly at risk of losing their license. Patients have also told me that they feel more alert on medicinal cannabis than other drugs, yet they still face penalisation for the former. Feeling more alert makes sense because cannabis is proven to have a lower crash risk than many other drugs.

As a doctor and cannabis patient I am now standing up to the government in favour of appeal of these unfair laws and this unfair situation. Until this happens, I’m left with the question: is it moral to obey immoral laws?

To help change these unjust laws, please sign the Drive Change petition.

For Blake, Queensland Drug Driving Laws are Unreasonable

Read time: 1 minute

Blake is sharing his experience as part of our “Personal Stories” series, which invites medicinal cannabis patients to share with the community how drug driving laws are impacting their quality of life. If you’d like to share your story, please email us at

It’s time that medicinal cannabis patients in Queensland are given driving defence. 

I’m a medicinal cannabis patient, and every day I worry that if I were to get drug tested that it would screen positive. 

It’s not fair that I should have to worry about this, since using my medicine doesn’t mean I drive when I’m impaired. Having access to medicinal cannabis has been a godsend for my condition, but knowing about the consequences if I test positive in a drug test only brings anxiety.

I use medicinal cannabis to treat my bipolar disorder. I’ve grappled with this for a long time, and access to medicinal cannabis has helped to save my life. 

However, the laws make it seem like the system still doesn’t accept medicinal cannabis. It’s unreasonable to suggest to people who use medicinal cannabis that they can “just go without for a few days” to be able to drive. The laws should take into account having THC in your system doesn’t mean you’re impaired.

I have the proper paperwork from the TGA, stating that THC may take up to five days for most of the THC to leave your system. To be able to work, I can’t wait that long before driving again. These laws are keeping me out of work and struggling to earn an income. If I choose to drive anyway, I am at risk of losing my license, even if I’m not impaired. It’s just not fair.

Open Letter to the Department of Transport and Main Roads: Are You Really Paying Attention to Road Safety?

Read time: 5.5

David Heilpern wrote a letter to the Land Transport Safety and Regulation department inquiring about the state of the current laws and in light of the research showing their ineffectiveness. The General Manager, Mr Andrew Mahon, answered this inquiry in a letter which we have attached below for reference.

The following is an open letter to Sussan Osmond, who Mr Andrew Mahon advised Drive Change to contact for further correspondence.

Dear Sussan Osmond,

I recently wrote to the Department of Transport and Main Roads expressing my concern over the ineffective and discriminatory drug laws in place for drivers. In this letter, I will address the Department of Transport and Main Roads directly.

What I presented to you was a concise report on how our drug driving laws are failing to improve safety as they discriminate against medicinal cannabis patients. While I appreciate your effort to offer a response, they were mostly evasive of the problem and prove that lawmakers aren’t relying on science or fact to formulate these laws. They are in need of an update. 

In your response, you went as far as to agree they are “difficult to address” but failed to present any scientific evidence in support of the need to uphold the current jurisdiction. This proves a clear need for deeper understanding of the issue. I will provide that to you, and the wider community, here. 

Cannabis as a drug

Cannabis is a drug that is proven to impair cognitive and motor function.

Mr. Andrew Mahon, Land Transport Safety and Regulation), QLD

In your letter, you address cannabis as a drug that is “proven to impair cognitive and motor function.” While this is true, it does not explain why the driving laws permit drivers to use other TGA-scheduled and over-the-counter drugs while operating vehicles. 

This is the true crux of the issue between medicinal cannabis and roadside drug tests. The chemicals in pharmaceutical drugs can be detected with such tests. Conversely, cannabis can remain at detectable levels in these tests far beyond the time of impairment. This clearly points to current practices as the problem. Why are we still using outdated methods for roadside drug testing if we know without a shadow of a doubt that they’re unreliable?

That truth is that yes, cannabis is a drug. The wider truth of it is that there are plenty of drugs which get protection or a pass when they are detected in roadside tests. It is nothing short of discriminatory to deny such rights to medicinal cannabis patients, especially when you consider the effects on road toll.

This has been an area that has been studied, and the results speak for themselves. The crash risk rate of drivers with a legal 0.05 BAC is 1.38-1.75. Once the BAC hits 0.08, this risk rises to 2.69. This is by far the highest crash risk rate of any of the other “impairing substances.” 

Medical cannabis and driving, by Thomas R Arkell, Danielle McCartney, Iain S McGregor, doi: 10.31128/AJGP-02-21-5840

Opioids are not far behind, presenting a crash risk of 2.29; Benzodiazepines carry a risk up to 2.30. Even antihistamines carry a crash risk of 1.17. So why then, if cannabis carries a crash risk of 1.11-1.42, is it the only of these drugs to be banned on the roads?

Discrimination, again, seems to be the only plausible answer. 

These discriminatory laws seem to be rooted in an outdated and unreasonable vilification of cannabis, one that doctors and scientists are committed to re-educating the public on. In some capacity, the government is already on board, having approved medicinal cannabis for therapeutic purposes, and there are 75,000 patients in Australia with legal prescriptions.

While these medical professionals have done their due diligence, there has been no accountability from the Department of Transport and Mains Roads, nor the police, in understanding that cannabis as a legal drug holds value in public health. 

Driving and Road Safety 

The role of drugs, in varying forms, is a growing problem for road safety, not only in Queensland but nationwide and internationally

Mr. Andrew Mahon, Land Transport Safety and Regulation), QLD

The TGA has categorised some forms of medicinal cannabis as a Schedule 8 Controlled Drug. Also in this class are Oxycontin, Sativex, Amytil, etc. So, why is it that patients who test positive for these conventional medications are not committing a crime while medicinal cannabis patients are?

In your letter, you mention that “The role of drugs, in varying forms, is a growing problem for road safety, not only in Queensland but nationwide and internationally.” I absolutely agree with you on this point, which is why I am so adamant about adjusting the laws surrounding them. 

The studies into road safety measures speak for themselves in this matter. After the introduction of seatbelts, there was a marked decline in road deaths. Likewise with airbags. In terms of roadside testing for cannabis, there has been no evidence that this decreases road toll. This points to the fact that we need newer methods of understanding what leads to crash risk. 

A “zero-tolerance approach” to selected legal prescriptions is clearly not the answer. 

You mention that we “take a zero-tolerance approach through presence based legislation as opposed to setting limits similar to alcohol,” but this argument is also untrue and shows the lack of research that’s been done on this topic. Tasmania has adopted laws protecting medicinal cannabis patients on the road. It proves that it is being done here in Australia and can be done throughout the entire country to defend medicinal cannabis users without a toll on road safety.

Yes, impairment increases risk of motor vehicle crashes–which is exactly what roadside drug tests should be looking for. You seem to understand this, saying that “impairments that will affect a person’s driving include their ability to anticipate hazards and unexpected situations, their decision making and their ability to respond quickly to changes in the traffic environment (e.g. reaction time).”

I ask again – why can other potentially impairing pharmaceutical medicines get a pass in roadside tests? Additionally, in testing for the presence of THC, which remains detectable past the point of impairment, it seems that there is no real evidence to back your claim that this is in the name of road safety when other harmful drugs are permissible and protected. 

The bottom line on mouth swabs is that they do not work. If they did, we would not have seen a 55% increase in road crashes between 2012-2018.

I do agree with you on one point, that medicinal cannabis cannot easily be tested at the roadside. The legislation stops short of the true issue: what can we do that can make road safety a priority, without a discriminatory framework that infringes on public health?

New and Improved Methods

The answer is not as elusive as you state it to be. In actuality, a simple impairment test can be completed. This has been successful  in jurisdictions around the world. It has even caught up to the technological age, and apps such as DRUID app takes the guesswork out of it. Why is it that the Australian governments want to hold on to archaic methods of testing for drug impairment. It seems odd to want to do so when the equipment is so expensive and road toll even more costly both financially and from a human perspective. 

I myself am acutely aware of these facts. But the truth of the matter is that the law is changing as our society begins to understand how to better care for our people. This is apparent when you consider the doctors, scientists, and lawyers who prescribe medicinal cannabis and/or support changing these discriminatory laws.. What is not apparent in your letter or in the law is why the Road Commission remains incredibly hesitant to take the step forward not only to assist in public health and putting an end to discrimination, but also into ways that have already proven capable of making our roads safer. 

We are calling on your department and other governmental organisations and those in Parliament to research the facts. This is integral to the protection and progression of Australian medicine. This is about public safety and the knowledge of the facts to help improve public health and safety. 

I trust this has given you some facts you may not otherwise have known.

The Drive Change team and more importantly patients who desperately need your assistance will await your response on this matter.

Yours sincerely, 

David Heilpern
Director of Change
Drive Change

The original letter sent to Drive Change can be found here.

The letter above is a slightly edited copy (due to the different medium) of this letter.

Cannabis Improved His Life After the Army, but Driving Laws Stand in the Way of His Freedom

Read time: 2 minutes

Cody is sharing his experience as part of our “Personal Stories” series, inviting medicinal cannabis patients to share with the community how drug driving laws are impacting their quality of life. If you’d like to share your story, please email us at

Hi, my name is Cody. I’m 30 years old living with my partner and two beautiful kids in the northern suburbs of Adelaide. I have been a medical cannabis patient since April 2021, but my journey began around 7 years ago.

In 2013 whilst serving in the Royal Australian Army, I suffered an acute knee injury that transformed into chronic pain. I have had multiple surgeries and countless hours of physiotherapy, none of which solved the problem. While I was dealing with this chronic pain, mental health issues began to develop. As a result, I was medically discharged in 2015. I had served 6 1/2 years.

Cody relies on a driver’s licence to keep his job and provide for his family. The drug driving laws pose a threat to his livelihood and his wellbeing.

Somewhere along the way, I had also developed a terrible relationship with alcohol, abusing it to numb both my body and mind. This lasted five years. I’m sober now, having not touched a drop since December 2020, but I attribute much of that success to my amazing family and psychiatrist.

In the past, I sought conventional drugs to cope with my struggles. Antidepressants and strong opioid-based medications have been regular medications for me since 2014. As time progressed, I began taking benzodiazepines and sleep aid medication.

In my experience taking these drugs over the years, I’ve had a handful of unintentional overdose experiences. It’s very concerning how easily this can happen. This ranged from skin itches and rashes to becoming violently ill and losing consciousness.

It would be safe to say that I’ve had my fair share of traditional prescription medication.

In an attempt to relieve me of my dependence on these troublesome drugs, I obtained a legal prescription for cannabis. It quickly became clear that there were benefits of cannabis on both my physical and mental state. I had no adverse effects from cannabis, leaving me stumped as to why medicinal cannabis wasn’t more widely accepted.

Starting to medicate with cannabis has been the best medical choice I have ever made. At least 90% of my medication is cannabis. As a result, my dependence on both opioids and benzodiazepines has plummeted.

However, the biggest problem I have with medical cannabis is the unfair and discriminatory drug driving laws across the country, specifically in my current state of South Australia.

Like a lot of people, I work and need a licence to do so. However, every time I get behind the wheel I run the risk of testing positive for THC at a roadside drug test, even several hours after the impairing effects have worn off.

It makes you feel like a bit of a criminal. Unfortunately, this is a common feeling amongst the medical cannabis patient community.

Medicinal cannabis patients shouldn’t have to choose between medicating or keeping a driver’s license and job. If someone is prescribed medicinal cannabis and they’re not driving impaired then they should not be guilty of an offence.

These laws need to change immediately, the current legislation is discriminatory, outdated, and maintained purely through ignorance.

I have seen and also personally experienced such a positive outcome that medical cannabis has to offer, I beg everyone involved in the legislation of this: please reform these unfair laws now.

You can help be an agent of change for these unjust laws by signing our petition.

One Size Does Not Fit All: Mick Palmer on the Need for Fit-For-Purpose Driving Laws in Australia

Read time: 3 minutes

This article is written by Drive Change ambassador and former Commission of the Australian Federal Police, Mick Palmer. Below, he shares his take on where the laws need improvement to protect medicinal cannabis patients and the community on the road.

There is a clear and well-understood correlation between impaired driving and road safety. Australia’s road toll is of broad community concern, and the Government’s effective policies–like the .05 drink driving legislation and speed cameras– should be applauded. However, Australia’s ‘zero-tolerance’ drug driving policy creates trouble for both patients and police. 


The government has already allowed for doctor-approved access to medicinal cannabis. This comes in response to the ever-growing scientific evidence, in addition to anecdotal evidence, that medicinal cannabis provides relief for people experiencing genuine pain and suffering due to a range of health issues, including terminal illness.

The government’s recognition of this evidence provides a step toward relief for thousands of Australians. However, for the legality of medicinal cannabis to fully operate as intended, the roadside drug testing protocol urgently requires amendment. 

I am not suggesting impaired driving laws should be weakened, but rather that they are updated to fit-for-purpose and aimed at achieving intended outcomes. 

To become fit-for-purpose, retain credibility, and operate fairly, driving laws must be aimed at dealing with impaired driving. Until this happens, many law-abiding Australians suffering from illness and often extreme pain will continue to experience legal and physical distress as a direct result of the discriminatory drug driving laws. 

“Police Leniency”

Likewise, police have a clear responsibility to effectively manage and apply the legislation in the community interest. The truth is that police exercise considerable compassionate discretion in their enforcement of drug driving laws every day. This is, in part, due to the driving laws being unfit-for-purpose and in need of review and amendment, or repeal.

The role of the police is to enforce laws, not make them. It is certainly a recipe for inconsistency to expect the police to cure legislative deficiencies by making personal judgments on patients. 

Furthermore, if police are screening for medicinal cannabis use but not for impairment, the laws are unfit-for-purpose and end up punishing people already coping with a terminal illness or serious pain.

Medicinal cannabis patients should not need to rely on the favourable exercise of discretion by police to escape punishment. It is up to Governments to have the courage and decency to legislate the necessary changes.

“Necessary Changes”

If there is any chance that medicinal cannabis can help people with terminal illness or serious pain, to lessen their pain and suffering and improve their quality of life, we should, as an educated and compassionate society, do all that is reasonably possible to facilitate access. 

The fact that these current drug driving laws exist is sufficient for many patients who qualify for medicinal cannabis treatment to decide not to take their medication. 

Some of these patients need to drive their motor vehicles as a matter of daily necessity. Sufferers should not be forced into situations where they may end up breaking the law to gain relief. Surely this is not the government’s intention.

The reality of current roadside testing is that they are not only discriminatory, but also invariably lead to further distress, fear, and embarrassment for the patients.

The resulting pain and suffering achieve the exact opposite of the intention of Governments in allowing legal access to medicinal cannabis in the first place. I am personally confident that this also is not the intention.

The facts speak for themselves. There is a better way to uphold law and road safety. We must be prepared to explore the options. 

As an example, Norway has successfully been assessing drug levels in driver’s systems for many years. This surely is far preferable to the continuation of a “zero-tolerance” approach that we have here, which can only be beaten by judicial discretion.

The current medicinal cannabis drug testing laws need to be subject to urgent review. By amending the laws, we move to ensure they operate fairly and without discrimination while continuing to achieve the intended outcome of controlling impaired and potentially dangerous driving.

Scientific Research: Cannabis Vs Other Drugs & Driving

Read time: 2.5 Min

Recently I co-authored an article called Cannabis & Driving, which was published in the Australian Journal of General Practice. The report reviewed the scientific evidence regarding cannabis and driving impairment. It also discusses the legal issues affecting patients and physicians.

The findings lead us to conclude that medicinal cannabis should be treated the same way we treat all other potentially impairing medications.

I’ve written this short article to summarise the findings for Drive Change, supporters of the campaign, and those fighting for equal rights for medicinal cannabis patients.


THC, put simply, is the part of cannabis that can get you stoned. It is used to treat a range of conditions, including chronic pain and chemotherapy-induced nausea and vomiting. 

On the other hand, CBD is non-psychoactive, which means that it doesn’t get you stoned. It is used to treat anxiety, psychosis, and some neurological disorders.  

When combined with THC, CBD may help reduce some of the adverse side effects of THC (e.g., anxiety and paranoia). However, this does not mean that CBD decreases the impairing effects of THC.

Cannabis and Driving

Scientific research shows that cannabis can impair driving ability and certain cognitive functions such as divided attention and working memory. These effects, however, are relatively mild and disappear as the body metabolises THC. 

Comparing cannabis and other drugs

When it comes to driving, current evidence indicates that a driver who tests positive for cannabis is approximately 1.1-1.4 times more likely to be involved in a crash relative to a sober driver. 

To put this into perspective, a driver with a legal blood alcohol concentration of .05 is approximately 1.3-1.8 times more likely to be involved in a crash relative to a sober driver. 

And a driver who tests positive for benzodiazepines (e.g., Valium) is approximately 1.2-2.3 times more likely to be involved in a crash relative to a sober driver.

It is important to remember that these are just estimates; these numbers could be higher or lower in reality. In a recent study of ours that looked at real-world driving performance, participants who had vaporised cannabis tended to have a very similar level of impairment to what we would expect to see in a driver with a BAC of .05. 

There is no evidence that CBD impairs driving at all.

What About Medical Cannabis?

Almost all this evidence comes from studies involving healthy volunteers who use cannabis occasionally. We know that people who use cannabis more frequently (e.g., daily) show less impairment than occasional users when given the same dose of THC due to the development of tolerance. 

Patients consuming cannabis daily and at doses that are therapeutic rather than intoxicating may be even less impaired. This is especially true if their cannabis use relieves an underlying condition that can impair driving, such as chronic pain. Research is currently underway to test this hypothesis. 


Overall, cannabis (and THC, specifically) appears to have a relatively minor impact on driving performance. 

However, it can produce significant impairment in certain situations, such as when combined with alcohol and when used by people who are unfamiliar with its effects. 

Patients who are using medical cannabis should be aware of these considerations and remember that it is illegal to drive if you have any detectable amount of THC in your system. In addition, you may still test positive for cannabis even if you are not impaired. And, having a valid prescription for medical cannabis does not exempt you from current roadside drug testing laws.

Drive Change Submission to NTC: Assessing Fitness to Drive

Read time: 1 Min

On the 11th of June 2021, the Drive Change Team responded to the National Transport Commission’s Assessment of Fitness To Drive Interim Report public consultation.

We were lucky to have a majority of our Ambassadors, Supporters and Friends sign on to the submission, which we believe shows great support for ending discrimination toward medicinal cannabis patients. Here are the organisations and individuals who supported our submission:

Drive Change NTC submission friends ambassadors and supporters

Submission Summary

The proposed recommendations state that healthcare practitioners are to determine a medicinal cannabis patient’s ‘fitness to drive’. This recommendation aligns with the current guidelines for all other prescribed potentially impairing medications such as opioid analgesics and benzodiazepines.

It does not change the liability of the healthcare professional from the current state. 

And, like all other medications, the doctor makes the initial assessment, but it is the patient’s responsibility not to drive whilst impaired.

The Drive Change Team, and all parties involved in the submission, agreed with the proposed recommendations. Passing these guidelines and amendments would be seen as a federal recommendation to create equal rights for medical cannabis patients. 

To read the complete submission, you can view or download the NTC Submission PDF.

Thank you to all of our Ambassadors, Supporters and Friends for their continued support toward making changes to these discriminatory drug driving laws.

An update on the VIC Medicinal Cannabis Patients and Driving Working Group

The Medicinal Cannabis Patients and Driving Working Group report has been in government hands for a few months. I am continuing to try and find the solution that will enable medicinal cannabis patients to drive when they are not impaired.

Currently, medicinal cannabis patients are effectively prohibited from driving due to the medication that they take, not because they are impaired. This is patently unfair and discriminatory.

For many patients, medicinal cannabis has enabled them to stop or reduce their use of opioids and benzodiazepines, which can be far more impairing. Sadly, we hear about patients who have gone back to these addictive and impairing medicines. They do this because they can continue to drive while taking them, despite getting better results and pain relief from medicinal cannabis.

Doctors advise patients about the risks of all medicines that may impair their ability to drive safely. But for patients taking medicinal cannabis, doctors are required to inform them that they cannot drive at all regardless of whether they are impaired or not. This is just a travesty when many of them are feeling alert and well because of this medicine.

I believe that we can provide a simple exemption for medicinal cannabis patients who have a valid prescription and sound doctor advice. As far as I am aware there is not a single case of a medicinal cannabis patient being in a car accident in Victoria in the five years that this medicine has been available.

I also made a note of the following commitment from Minister Leane recorded in Hansard:

“I want to restate our government’s commitment to Ms Patten that we are really keen to work with her on this particular issue. We are going to work with Ms Patten on the outcome to ensure people are not disadvantaged by taking their medication.”

I can assure you of my ongoing commitment to Victorian doctors, medicinal cannabis providers and, most importantly patients, that we are addressing this discriminatory and unfair situation.

Fiona Patten MP
Member for Northern Metropolitan Region
Parliament of Victoria
Legislative Council
An Ambassador for Drive Change

The Truth: Roadside Drug Testing Doesn’t Reduce Road Trauma

At Drive Change, we lobby to exclude medicinal cannabis users from the draconian drug driving detection laws. There are numerous reasons these laws are just plain wrong. But, one of the arguments we keep coming up against is road safety. Opponents of law change are adamant that these laws are designed to improve road safety. 

The fact is – our current drug driving laws do not improve road safety. 

This blog analyses the current drug driving laws and road safety and provides evidence for why these laws must change.

Correlation and Causation: The Basics

It is stating the bleeding obvious that there is a distinction between correlation and causation. 

Just because two things occur does not mean that one causes the other. There are some marvellous websites that exemplify the difference between causation and correlation. My favourite one contrasts the purchase of cheese per capita and the number of people who die from becoming tangled in their bedsheets.

Stunningly, this correlation can be mapped by double lined graphs for decades. These results certainly do not prove that eating cheese causes death in this manner or that death in this manner leads to eating more cheese by the bereaved. It is possible, of course, that these two arguments are true – but it is more likely that there are other factors at play. In that case, the old demon of coincidence. 

Yet this classic and basic error is repeatedly made in drug detection driving and road trauma. 

Just because individuals who died in car accidents had a drug in their system does not mean the drug was the main cause of the accident, particularly relating to cannabis medicine.

Examples of Over-Egging the Pudding

Every time someone mentions law reform, someone else will trot out the tired old argument that the presence of illicit drugs in your system leads to more deaths and injury on the road. 

For example, in opposing drug driving law reform in NSW in 2020, Scott Farlow MLC stated in parliament:

“NSW crash data indicates that since 2014 there has been a 7% increase in the number of fatalities and serious crashes directly attributed to the presence of an illicit drug.”

The media, even responsible mastheads, often do not help. For example, there is this headline from the Sydney Morning Herald, also in 2020:

“On Ice or Doped Out – Drug driving deaths rise across Australia.”

This article boldly declares that drugs contribute to one in five deaths in New South Wales and cites research by Dr Mathew Baldock (more on this shortly).

“Driving with drugs in your system is not only illegal, it’s extremely dangerous and puts your life and the lives of all other road users at risk.”

Unfounded statement by the Director of Road Safety in NSW

And all this “research” leads to fiction-based declarations like this by police, politicians and, in this case, the Director of Road Safety in NSW.

Research Findings: No Causation

In NSW, the research shows that in the nine years from 2010 to 2018, 21 per cent (384) of the 1818 drivers or riders who died on NSW roads had an illicit drug in their system. In Baldock’s study, it was over 15%, with around 9% amphetamines and 6% THC. There are other similar studies with results in that range. 

However, nowhere in the actual published research is there anything like proof of causation. 

In other words, there is nothing to suggest that even just one of those deaths was caused by the presence of drugs, a classic example of confusing correlation with causation.   

A careful analysis of Baldock

In South Australia, as in other states, those killed in road accidents are subject to mandatory blood tests. The cut-off level for THC is two nanograms. In the Baldock study, they tabulated the results of this and found that around 6% of those who died had a detectable level of cannabis in their system. 

And from this, the authors and others have claimed a causative connection – THC presence leads to deaths. To those blessed with the knowledge of correlation/causation errors, the problems with this argument become immediately apparent. 

To show causation, one would need first to prove that at this level, drivers were adversely affected by the THC in their system. Given that cannabis can be detected for up to six days in the blood, that would be impossible.  

Second, there would need to be evidence that the driver was at fault. There is no analysis of this in the research, and many of those may have been the innocent driver. We’ll never know. 

Third, there would need to be research showing that 6% with THC presence is higher than the norm amongst the population profile of those who died. Research shows that around 30% of those aged 18 to 24 have recently used an illicit drug, with cannabis use by far the most common.

It is entirely possible that the 6% figure is an underrepresentation. Of course, that does not mean that cannabis consumption makes drivers safer either – that would be confusing cheese and bed strangulation as well.

Fourth, to rely on this research to make the causation argument, one would hope to find a single statement linking the presence and the deaths within the published study itself. There is none. And that is because the authors would not want to be the laughing stock of their peers for making a research 101 error. 

Fifth, there is not one iota of evidence that a single driver was driving while taking medication under a prescription. The demographic profile of those with prescriptions for cannabis containing THC is markedly different from those who are most commonly involved in fatal motor vehicle incidents.

According to TGA, the average patient is about 50 years old, female and has access to private funds for expensive medicines. Further, they are actively seeking to minimise the psychoactive effects – they are not using a bong at a party, getting in a car and having a collision on the way home. 

Finally, there is no evidence that these laws have reduced the road toll at all in any jurisdiction in Australia. When random breath testing for alcohol, seatbelts, speed limits and airbags were introduced, there was a marked decline in the road toll.

Although there are over 500,000 drug driving detection tests per year, there’s still no evidence the roads are safer due to random roadside testing. 


There is no correlation between the presence of THC in saliva and impairment. More importantly, there is no evidence that driving with a detectable level of THC increases the risk of road trauma. 

Efforts to link the two exemplify a classic case of confusing correlation with causation. This mischief is not just inaccuracy; it serves to provide a significant hurdle to reforming laws that unjustly and unjustifiably discriminate against medicinal cannabis users.