A scientific dilemma
The study by the SGRM presents the various approaches to assess the ability to drive in Recreational Consumption under the influence of THC:
- Impact-oriented approach: Here, driving ability is assessed on a case-by-case basis - a very complex process.
- Per se approach: A fixed limit is defined above which the ability to drive is considered impaired.
- Zero tolerance approach: Any detection of THC in the blood leads to the assumption that you are unfit to drive.
A modified zero-tolerance approach currently applies in Switzerland with a limit of 1.5 µg/L THC in the blood . However, this limit does not take into account individual tolerance or the effects of THC in long-term users, especially patients who take cannabis for medical reasons.
The study comes to the conclusion that an effect-based limit for THC – as with alcohol – is not scientifically possible. Instead, a per se approach with a slightly raised limit of 1.7 µg/L in whole blood proposed in order to rule out any relevant impairment of driving ability.
Fitness to drive and ability to drive while using medical cannabis
People who take cannabis for medical reasons on a doctor's prescription are not automatically fit to drive. Participation in motorized road traffic should only take place after a positive traffic medical assessment. This test takes into account the underlying diseases, their drug treatment, the indication for cannabis therapy, individual tolerance and consumption behavior with regard to psychotropic substances such as alcohol, cannabis or other drugs.
According to current Swiss law, there is generally a “zero tolerance” for THC. However, there is an exception if preparations containing THC have been prescribed by a doctor. In these cases, driving ability must be assessed individually. Doctors are obliged to inform patients about their ability to drive while taking THC medication as part of the so-called safety information. Ultimately, the responsibility to only take part in road traffic when able to drive lies with those affected themselves.
If incidents do occur in road traffic, the driving ability assessment is carried out as part of a so-called 3-pillar report. This includes police observations, medical examination findings and forensic toxicological analysis results. Driving-relevant effects of the underlying illness or other prescribed medication are also taken into account in the assessment.
However, a crucial problem remains the lack of legal certainty. Without clear, confirmed driving ability, there is a significant risk of losing insurance coverage in the event of an accident. Benefits may be denied if it is proven that the ability to drive was impaired by the THC medication. This legal and financial risk makes it clear how important transparent and reliable regulation in road traffic is.
The Association MEDCAN is committed to addressing these injustices. Differentiated approaches are needed that take into account the individual circumstances of those affected and give them a fair chance to preserve their mobility and their rights.
Here you can find the entire report from the Swiss Society for Forensic Medicine (SGRM), carried out on behalf of the Federal Roads Office (FEDRO).
From the perspective of those affected, this is unfair treatment
The scientific results are an important contribution, but what does this mean in practice? Our experience as Association MEDCAN shows that many chronically ill people are massively restricted due to the current regulations - restrictions that not only make everyday life more difficult, but can sometimes have existential consequences.
A patient has confided in us their story - two examples that represent the numerous challenges that many of those affected struggle with. Their experiences demonstrate the urgent need for changes in practice to ensure access to safe and fair treatment.
“Either cannabis or a car.”
A man from the mountains, who consumes a minimum amount of 0.5 g of cannabis flowers with a THC content of 25% every day and is therefore well and safely adjusted, experienced a real nightmare. He depends on his car - not only for getting to work, but also for maintaining social contacts and managing everyday life. The nearest public transport connection is six kilometers away and almost inaccessible in winter.
After a house search - triggered by the possession of cannabis flowers - the case was reported to the traffic office. He had to undergo a level 4 report, during which the doctor told him: “Either cannabis as medicine or car.”
In order to keep his driver's license, he stopped taking his medication immediately. Since then he has again suffered from chronic sleep problems and nightmares and a significantly worse quality of life. He also has to provide regular urine samples for at least a year to prove his abstinence - a measure that is associated with high costs.
“In order to stay mobile, I had to go through an odyssey.”
The second story we received also shows the profound impact of the current regulations. Andrea, 55 years old, is immunocompromised and lives with chronic fatigue and joint pain. She relies on her car to cope with everyday life because stressful situations such as hasty changes to public transport are unthinkable for her.
After a routine check by the IV, the road traffic office was given access to her complete file - including details that had nothing to do with her ability to drive. Her driver's license was revoked because of her THC medication.
The consequences were devastating: Andrea had to stop the therapy and switch to other medications that had serious side effects. Only after months of abstinence and another report was she allowed to drive again under strict conditions. Ironically, tests showed that their reaction speed was better with THC in their blood than without .
You can read Andrea's full story here.
The position of the Association MEDCAN
In practice, the current regulations lead to massive injustices. We demand a differentiated regulation that distinguishes between actual impairment and purely positive THC detection. It cannot be the case that those affected with stable medication and proven driving ability are excluded from road traffic.
For many chronically ill people, especially in rural areas, the car is essential for managing everyday life. Revoking your driving license can have existential consequences and promote social isolation.
Travel responsibly
As Association , we would like to emphasize that cannabis patients do not want to drive while intoxicated. On the contrary, they care deeply about using their cars responsibly.
However, it is important to understand that the effects of cannabis are very different than those of alcohol. While alcohol breaks down linearly in the body, THC – the psychoactive ingredient in cannabis – remains detectable in the blood for much longer. This means that you can still test positive for THC days or even weeks after taking it, even though there is no longer any adverse effect.
The current statutory limit values for THC in road traffic are designed for the Recreational Consumption and do not take into account the situation of patients who take stable doses and do not experience any intoxication. These limit values mean that many people lose their mobility, although they can handle their medication responsibly and be able to drive safely.
As Association we are committed to ensuring that these differences are better understood and taken into account in legislation. Our goal is to ensure that those affected are not treated unfairly and do not lose their mobility just because they are taking necessary medication. Responsibility and safety in road traffic remain our top priority.
An appeal to politics
The Association MEDCAN is committed to ensuring that the regulations are adjusted. Our demands:
- Introduction of a realistic control system that does not discriminate against medical users.
- Individual assessments that are scientifically based and carried out fairly.
- Protecting the data of those affected to prevent arbitrary decisions.
We call on everyone to work for a fairer transport policy. Together we can help chronically ill people remain mobile despite their medication and be able to lead a self-determined life. Become a member or support us with a donation .
