Using CBD and driving: should you choose?

CBD, or cannabidiol, is a non-psychoactive substance known for its many benefits, but less so for its possible effects when driving. Although legal in Switzerland if it contains less than 1% THC, it is still associated in people's minds with the psychoactive effects of THC, which is of course illegal and incompatible with driving. So what does science say about the impact of CBD consumption on road safety?

Consuming CBD and driving: there is no requirement to choose. 2 recently published studies, one in September 2021, the other in December 2020, reveal that CBD-dominant cannabis consumption does not affect driving ability.

Using CBD and driving: should you choose? 4

One such study, published in December 2020 in the Journal of the American Medical Association, was led by the Lambert Initiative for Cannabinoid Therapeutics at the University of Sydney. It involved 26 participants who "vaped" cannabis containing different ratios of THC and CBD, then drove a 100-kilometer route under controlled conditions on public roads. For Dr Thomas Arkell, the result was very clear: "CBD does not affect driving ability".

What does the first global study on the effect of CBD consumption on driving say?

"To our knowledge, this is the first study to evaluate the potential impact of this consumption on road safety," explain the authors of the Swiss study published a few months ago, Tim J. Gelmi, Wolfgang Weinmann and Matthias Pfäffli.

Source :

Published in a recognised organisation, PubMed, which brings together 33 million articles and studies related to biology and medicine, the authors set themselves the ambitious goal ofevaluating the impact of CBD on psychomotor and cognitive abilities related to driving. In short, it is everything that helps us to analyse a situation, make a decision and react once we are behind the wheel.

In this approach, 33 volunteers were divided into 2 groups. One group received a placebo while the second group consumed CBD-dominant cannabis (16.6% CBD and 0.9% THC, below the legal threshold in Switzerland of 1%).

These volunteers then underwent :

  • On the one hand, tests that are part of a measurement system commonly used (in 26 countries) to assess driving ability,
  • secondly, balance and coordination exercises regularly used by police officers in Switzerland in the event of a traffic offence or control, to see if there are any physical impairments due to drug or alcohol consumption.
impact of cbd on balance and coordination
Motor and cognitive performance were analysed in this study.

Reaction time, behaviour in stressful situations, ability to concentrate, balance, coordination, blood pressure, ... Everything has been evaluated and recorded to establish what, if any, risks are involved when driving.

What conclusions?

The conclusions are very clear: 

  • "Between a person who has consumed CBD-dominant cannabis and a person who has had the placebo, there are no significant impacts on reaction time.
  • "No change was observed in terms of behaviour, psychomotor skills, ability to orientate in space, mood swings, ability to converse.

Focus on reaction time

When one thinks of the association between cannabidiol and driving, one might think of slowing down reaction time and reflexes. But the figures are there: in the series of tests based on light and sound stimuli, the group that consumed the cannabinoid had an average reaction speed of 60.6 s, while that of the placebo consumers was barely better (61.0 s). Only one blink of the eye (0.4 s on average) separated the two averages.

CBD does not affect coordination

In order to prevent accidents on the road, you need to be able to rely on your coordination. In this global study, the researchers found that out of 66 coordination tests, 6 were outside the so-called normal reaction time range of 20 to 45 seconds. 

Interesting to note: of these 6 cases on the margin, only one concerns a person who took CBD (the hypothesis being that this person may not have understood the instructions). The other 5 cases are in fact only from people who had the placebo. 

What if CBD compensated for the negative effects of THC?

Researchers have established that CBD helps to regulate the negative effects of THC:

  • tachycardia, 
  • anxiety, 
  • perspiration, 
  • difficulty in concentrating, ...

So there is a real reversal that can take place! When these two cannabinoids are combined in the right ratio, it can erase the known negative effects of THC. So it's the same family but with different effects.

Using CBD, driving: what to expect when you are checked?

consumption and control: what is allowed
Using CBD and driving: should you choose? 5

In Switzerland, consuming CBD is legal if the THC threshold is set below 1%. But what can you expect when you drive: withdrawal of your licence, complaints during a roadside check, penalties, etc.? At what dose can one be considered positive during a police check or other anti-drug check?

As this cannabinoid is legal, there is no risk of testing positive for this substance. The question is more about how concentrated the products are in THC.

In an information sheet on the regulation of cannabidiol consumption in relation to driving, the Federal Office of Public Health (FOPH) provides several elements based on a study carried out by the Institute of Forensic Medicine of the University of Basel*. In particular, the limit value for THC is 1.5 micrograms per litre of blood. This means that a person who is tested with this value during a control is automatically considered unfit to drive.

Source: Bucher, B., Gerlach, K., Frei, P., Knöpfli, K., Scheurer, E. (2020): Bericht THC-Grenzwerte im Strassenverkehr - eine Literaturanalyse. Institut für Rechtsmedizin der Universität Basel, Basel

Warning: with the Sicura law In Switzerland, saliva tests carried out on the road are used to determine whether or not THC has been consumed, regardless of the level. If the answer is positive, and even if the level detected is below the punishable level, the driving licence is withdrawn.

Only after the samples have been analysed, i.e. the true THC concentration in the blood has been determined, can the driving licence be restored (if it is below 1.5 µg/L). This can take several months.

2 issues: concentration and timing of consumption

So there are two things to watch out for: 

  • the THC concentration of the products: whether it is cannabis flowers, oils or other edible products which can all, according to the mode of production, present an absence of THC or a high rate thus positive during a control
  • the time of consumption. In expert studies, the THC level in the blood is 2.6 micrograms per litre of blood immediately after consumption, while 45 minutes later it is 0.9 mg/mL. The Australian study shows that 4 hours after consumption of moderate to high THC cannabis, there is no effect of THC on driving.

Driving and using CBD is not for you? You can use broad spectrum CBDoil, which is what is found in our THC-FREE Wellness oils. This is CBD extracted from hemp or cannabis and processed to remove THC from other cannabinoids.

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