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

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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 Why are we still using outdated methods for roadside drug testing if we know without a shadow of a doubt that they’re unreliable?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.

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.

How to argue with those who support drug driving testing

We are now at 200,000 tests each year in NSW. Similar numbers in Victoria. Tens of thousands in every other state. I reckon we will be close to a million next year. That is a frigging big number. I have spoken in the press for a solid nine months.

The Drive Change campaign, which is fighting for equal rights for legal medical cannabis patients has had no refutation. Not one word of justification from the police or the road safety gurus. And that is because it is unjustifiable. Here is a response to those mythical people (do they exist?) who seek to justify Australia’s current drug driving practices.

Argument 1: But it’s random, so your chances of getting caught are minuscule.

It is not random. First, the police utilise number plate recognition to identify and test ‘suspicious’ vehicles. This, of course, includes vehicles where the driver has previously been in contact with the police and even more those who have previously been dealt with for drug detection driving. Second, the testing sites are often set up outside music festivals and in areas where drug use is high. And let’s not even talk about Mardi Grass blanket testing.

Argument 2: It’s a road safety measure.

It is not a road safety measure – it is a prohibition measure. If it was a road safety measure, it would have been ditched by now because there is no evidence that it has impacted the death or injury toll at all.

When random breath testing, seatbelts, airbags and 50km speed limits were introduced, all had a noticeable, provable impact on the road toll. Not so with drug driving measures. And this is not surprising given that it does not test affectation – see 3 below.

Argument 3: It stops people driving under the influence.

There is a separate offence of driving under the influence. In the thousands of cases of drug driving I dealt with as a Magistrate, I did not see a single set of facts alleging that the person was adversely affected by the drug.

And that is not surprising because they would have been charged with the other, more serious offence if they were. Besides, the testing levels are so low they do not equate to affectation at all – unlike alcohol.

Argument 4: But cannabis is illegal anyway.

That is true for some cannabis, but not for all. Cannabis is now prescribed widely in Australia with the approval of every government in the country. Even those with a prescription are subject to these laws. It is legal to use cannabis in many places in the world, including the Australian Capital Territory.

I saw many people who had returned from these places days ago and were still detected under the current regime. They had not committed any crime. Secondly, there are many illegal things (rape, murder, theft, domestic and family violence). Of course, none of these leads to a loss of licence because none make our roads more dangerous. The presence of THC in your mouth does not necessarily make you or your driving more dangerous.

Argument 5: Death and Injury stats show that illicit drugs are the major cause of road trauma.

This is false, and studies that seek to prove this are either anecdotal or unreliable. The major substance cause of death or injury is, in order: 

  1. Alcohol
  2. Prescription drugs.

One study seeks to connect high rates of cannabis detection in those who have died in motor vehicle incidents with road trauma. However, this study specifically does not make any causation claims. The detection levels are 2 nanograms, which no one seriously suggests has anything like a negative influence on driving. The counterarguments are pretty clear.

Argument 6: But it’s only a traffic offence – you don’t get a criminal record.

This is not true either. 

Although there are some differences between states, in essence, any conviction (or even where the offence is found proven, but a conviction is not recorded) still has significant impacts on employment, insurance and travel. No matter how it is defined, you also have a police record and court record of the suspension, fine or disqualification.

Argument 7: Well, it discourages drug use, and that must be a good thing.

It discourages some drug use, particularly cannabis. It does not discourage

  • Alcohol
  • Prescription drugs
  • Opioids including heroin
  • LSD
  • Magic mushrooms or
  • Many synthetic drugs. 

Also, cocaine is not tested in some States. 

Cannabis is fat-soluble and can remain in your system for a very long time, long after you’re impairment (if any) ends. And with cannabis patients, impairment is rare.

This testing methodology also encourages the use of amphetamines and cocaine because although they are detectable, the word on the street is that you are clear of those within 48 hours. And that is probably correct. I have yet to see a public health argument that supports these drug choices over medicinal or responsible use of cannabis.

Argument 8: Nowhere else has granted a medicinal exception because it is technically impossible. 

This is just not true. Tasmania has a medical/prescription exception, and the sky has not fallen in. Also, there are medical exceptions in the United Kingdom, Ireland, Germany, Norway and New Zealand. There are proposals for change before the Victorian and South Australian parliaments

Those who oppose medical exemptions generally have a vested interest – the police, big pharma and the alcohol lobby. Bizarrely, in NSW, there is a medical exemption for morphine, but not for cannabis. Go figure. 

Argument 9: It does not affect your insurance if it is only a detectable level. 

Well, let’s have a look at this policy from AAMI where there is an exclusion if your car is being driven by “anyone who had more than the legal limit for alcohol or drugs in their breath, blood, saliva or urine as shown by analysis”. 

Given that the legal limit for detection offences is zero, this poses real problems for those following their doctor’s directions or an illicit user with a minute detection. 

Argument 10: Prescription drugs are safer for drivers than cannabis. 

No evidence shows this. In fact, there is plenty of evidence that those who use cannabis on prescription reduce their use of prescription drugs, particularly opioids – generally by half. In other words, there is a strong argument that drivers with merely detectable levels are likely to be less affected than if they are driving on prescription drugs.

And this makes sense – we all know people who are using medicinal cannabis for (say) generalised pain and, as a result, use much fewer prescription medicines like opioids and benzodiazepines. 

Tammy Franks Invites Drive Change Team To South Australian Parliament

Read time: 3 Min Read

Blog cover image by hypnotiseme.

A bill for change.

On Wednesday, 3 February 2021, I addressed a roundtable meeting of parliamentarians in Parliament House Adelaide via Microsoft Teams. This was at the invitation of Tammy Frank, Greens MLC. Tammy has been a Greens member of South Australia’s upper house since 2010. The roundtable was organised to coincide with the introduction of a bill in the upper house. The bill recommends a framework to provide a medical defence to the offence of drug-detected driving for legal medicinal cannabis patients.

Drumming up support.

There were 15 members of parliament or staffers present and Dr Joel Wren, a local medicinal cannabis prescriber. I was asked to speak to the group as the Drive Change Campaign Lead to outline my experience with drug driving laws and why they needed to change. Tammy requested that I focus on distinguishing between driving under the influence and drug-detection driving in an effort to get bipartisan support for her bill. 

Tammy described her motivation for changing the laws when they were introduced to parliament as follows: 

“Australia is the only jurisdiction that prevents medicinal cannabis patients from driving while they are using their prescribed medication, even when they are not actually impaired,” she said. “Our current laws are based on stigma, not science. Medicinal cannabis patients deserve to be treated the same as any other patient who is taking prescribed medication.”

The slides below outline the content of my speech to the roundtable.

Questions & answers.

There was a selection of questions that highlighted common concerns. I addressed these questions with answers from a previous blog post, “How to argue with those who support the current drug driving regime” (To be published on Drive Change soon). 

One little known fact which I highlighted is that Tasmania has had a medical defence for over five years, and there have been no reported problems as a result. 

There was one question and answer that is worth highlighting, which I have paraphrased below. 

Q: If these laws go through, what is to stop a person from having four bongs at lunchtime, driving, and then relying on these laws to excuse his danger to the community. 

A: Imagine if you substitute cannabis at lunchtime for four Valium tablets. The police would have the power to stop, detain, blood test and suspend the driver as soon as they formed a reasonable suspicion that he was driving under the influence of a drug – any drug. 

The defence would only apply if the driver was prescribed, taking cannabis as per the prescription and not driving under the influence. So, the community would be protected in the same way that they are currently protected for all other prescription drugs. 

There would not be any increased risk to the community, and only those who were not a danger would be able to rely on the defence. 

This was a valuable opportunity to directly address lawmakers on the benefits of changing the drug laws under the Drive Change campaign’s banner. Time will tell if the bill becomes law in South Australia, but at the very least, the parliamentarians had the opportunity to hear the key messages of our campaign. 

Positive momentum.

In the last few months, there has been legislative action in New South Wales, Victoria and South Australia. In each case, Drive Change has been at the forefront of supporting the initiators of change and liaising with other parliamentarians. 

We are actively in discussions in the ACT, and of course, Tasmania is the exemplar of existing provisions. In the South Australian examples, we were approached to provide statistical and practical support for their initiatives, which shows that Drive Change is starting to make a mark where it counts. 

Of course, the proof will be in the pudding, and Victoria is likely to be the first mainland jurisdiction to change. I suspect that the next parliamentary focus will be the ACT, where cannabis possession has been effectively legalised.  

Drug law reform in Australia is glacially slow. Even the most sensible and minor changes face resistance from entrenched private and public institutions, as well as sensationalist opposition from the tabloid and shock-jock sections of the media. But we will not be daunted or demoralised because in the back of our mind are those patients whose lives are being ruined by these unnecessary, counterproductive laws and the medicinal cannabis industry that faces huge hurdles while ever they remain.