Cannabis and fitness to drive
Preliminary remark
Dear visitor to my website,
I would have liked to provide you with a detailed, up-to-date text on this page containing everything you need to know about cannabis and driving ability. However, I am afraid I will have to disappoint you, at least in part. I am unable to provide such a text here or in the foreseeable future.
Since the new Cannabis Act (CanG) came into force, there has been chaos in the courts, among authorities, and at assessment institutes. It will take months, perhaps even years, before legal certainty prevails and everyone involved in your rehabilitation knows what the situation is and what they or you have to do.
However, I do not want to leave you without any information. On this website, you will find the latest information that I have gathered from the internet, the Federal Ministry of Health, professional associations for traffic psychology, various court rulings, and discussions with driver's license authorities and professional colleagues, including consultants and MPU assessors.
Please assume that the assessment of the situation and the information you receive here are subject to constant change. New court rulings and procedural instructions will determine the approach taken by the driver's license authorities. Specialist conferences and additions to the assessment criteria for driving aptitude will result in binding regulations for experts.
All of this is difficult for outsiders to understand. Therefore, please do not hesitate to call me and ask about the status quo, i.e., what currently applies. Beyond the possibilities opened up by the new legal situation, there is a practice of assessing driving aptitude that only those who work in the field are familiar with.
Regardless of the legalization of cannabis, will I still have to provide proof of abstinence in the MPU, or can I try controlled consumption and separating smoking cannabis from driving? Will my own commitment be enough, or will I be required to undergo traffic therapy to confirm that I have familiarized myself more thoroughly with the subject matter and my case? And can't I just go to my doctor and get a prescription for medical cannabis so that I can legally drive with THC in my blood? I would be happy to discuss all of this and more with you on this page.
If the questions and information raised here confuse you and you would like to know how things stand in your specific case, we can of course arrange a consultation, during which we will discuss your personal situation with reference to your driving licence file. You can reach me at the office on (089) 291 651 63.
Finally, please allow me to add the indispensable statement that the information you can read here has been carefully compiled, but nevertheless represents my personal opinion, as psychologists are not permitted to provide legally binding information.
1. The new law: Cannabis possession and consumption
Let's start with the new law. You probably already know most of it, but it doesn't hurt to briefly summarize it, as everything that follows is based on it.
After years of back and forth between proponents and opponents of cannabis legalization, and following similar laws in other European countries, the “Law on the Controlled Use of Cannabis and Amending Other Regulations” (also known as the Cannabis Act or CanG) has now come into force, with April 1, 2024, and July 1, 2024, as the effective dates, and regulations on the deletion of entries from the Federal Central Register that are no longer punishable under the new law came into force on January 1, 2025.[1]
Since April 1, 2024, adults have been allowed to consume cannabis legally. Since July 1, 2024, you have been allowed to grow cannabis for personal use within certain limits. Further provisions deal with cultivation associations and commercial cultivation. Precise information on this can be found either in the law itself or on relevant internet portals, such as the website of the Federal Ministry of Health. For example, every adult may grow up to three cannabis plants for personal use and may possess and carry up to 25 grams of cannabis or dried cannabis plants; At home, in your apartment, you can even have 50 grams.[2] You may share the cannabis you own with friends within certain limits in so-called cultivation associations. Synthetic cannabis is prohibited. You are also not allowed to offer your friends cannabis and alcohol at the same time, and compliance with these conditions is, of course, monitored and controlled by the state.
Further regulations concern the transfer of cannabis seeds to third parties, the handling of mandatory documentation of the quantities sold, the obligation to inform buyers, and the requirement to consume cannabis as discreetly as possible out of sight of minors.
We do not want to go into further detail here about possession or cultivation, as you can read all about this on the relevant websites. Suffice it to say that you are allowed to possess or cultivate a certain amount of cannabis and that you are also allowed to consume this cannabis, provided that you are at least 18 years old. Young people are excluded from consumption and possession.
2. Cannabis and road traffic
An uninformed observer of the new legislative initiative might ask a simple question: if the possession and consumption of cannabis is legal within certain limits, what is the problem with participating in road traffic? The answer is easy to find if you compare it to alcohol. The consumption of alcohol is legal, but driving while intoxicated is not. So let's take a closer look at the situation with cannabis.
As a general rule, anyone who participates in road traffic must be fit to drive. This simply means that you must meet the health requirements for driving motor vehicles, i.e., you must not have any illnesses that impair your ability to drive. However, this also means that you must not drive under the influence of substances that are likely to impair your ability to drive, more specifically: drugs, alcohol, and cannabis.
As you may be aware, the legislature has removed cannabis from the schedules and scope of the Narcotics Act[3] and confirmed the status of this substance as a recreational drug. This has also led to significant easing of the rules for prescribing cannabis in a medical context, a fact that we will encounter below in our assessment of medical cannabis in connection with road traffic. However, it cannot be denied that it is still a psychoactive, i.e., mind-altering substance which, due to its particular effect of impairing reaction times, can affect a person's ability to drive.
This raised the question of when such a risk posed by cannabis in road traffic can be assumed, or rather, at what critical THC level in the blood a corresponding violation of the rules in the form of an administrative offense exists. A commission of experts was commissioned to issue a scientifically based recommendation on this matter. Politicians adopted the limit of 3.5 ng/ml that was ultimately agreed upon and incorporated it into the new law. Since it came into force on August 22, 2024, it has been prohibited to participate in motorized traffic with more than 3.5 ng/ml THC in the blood. There is also a ban on cannabis for novice drivers[4] and a ban on the combined use of cannabis and alcohol. For the sake of completeness, we would like to add that the stricter provisions of the Criminal Code (Sections 315 and 316 StGB) continue to apply, which prohibit driving under the influence of narcotics, i.e., in a state of severe intoxication, that impairs driving safety.
3. Cannabis and fitness to drive
At the same time, the legal situation regarding driving under the influence of cannabis was brought into line with the existing alcohol regulations, i.e., a new paragraph was added to the Driver's License Regulation (FeV), which reads like the existing alcohol paragraph, except that the term “alcohol” has been replaced by the term “cannabis.” Let's take a closer look at this paragraph to get a feel for what has changed and when cannabis consumption conflicts with driving ability.
Cannabis Dependence
It will come as no surprise to learn that cannabis dependence excludes driving ability. Although it was still unclear whether this referred to psychological or physical dependence, the literature quickly agreed that, as with alcohol dependence, physical dependence should be assumed.
Of course, according to current knowledge, there are no clear toxicological markers or cannabis limits that allow such dependence to be concluded with certainty. Even very high THC or THC carboxylic acid (THC-COOH) levels do not indicate physical dependence on our drug. Similar to alcohol, a doctor or qualified psychotherapist, ideally working in a clinic or other addiction treatment facility, would have to diagnose physical cannabis dependence, which is likely to occur in very rare cases. We can therefore disregard this variant of externally diagnosed physical dependence that excludes fitness to drive, as very few drivers fall into this category, proof of dependence cannot be provided, and the driving license authorities will not engage in labor-intensive legal disputes with lawyers.
B. Cannabis abuse
Doubts about fitness to drive are of course also possible if cannabis abuse is present “or other facts justify the assumption of cannabis abuse.” Furthermore, repeated, i.e., at least two instances of driving under the influence of cannabis, trigger doubts about fitness to drive, as does the revocation of a driver's license due to driving under the influence of cannabis. In all these cases, the driver's license authority will order an MPU to “clarify whether cannabis abuse or cannabis dependence no longer exists.”[5]
Let us pause for a moment to consider this rather cryptic wording of Section 13a of the Driver's License Regulation. An MPU is always ordered in the case of two instances of driving under the influence of cannabis above the critical limit of 3.5 ng/ml. However, it is also ordered in the case of a single instance of driving under the influence of cannabis if there are additional facts that justify the assumption of cannabis abuse. In this case, it is assumed that the person concerned can no longer be expected to safely separate cannabis use and driving.
For you as a driver, this legal text and its interpretation by the driver's license authority have a very simple consequence. If you are caught driving twice with more than 3.5 ng/ml, an MPU is required without exception. If, on the other hand, you drive under the influence of cannabis once with the corresponding amount, it depends on other circumstances of your individual case, the so-called “additional facts” or “related circumstances,” whether the driver's license authority orders the MPU or not.
You would certainly like to know what these facts are, and of course I do not want to withhold any information that can be provided. However, I would like to issue a warning in advance. The criteria in question are set out in various texts and recommendations issued by professional associations. Driving license authorities also cite one or two judgments in order to protect themselves legally. There is no clear formulation of these criteria, i.e., a definitive determination of when which additional facts trigger an MPU, and there is unlikely to be one in the foreseeable future. The responsible clerk at your driver's license office will adhere to the guidelines of their agency, i.e., implement the current internal procedure. In borderline cases, the driver's license authority will order an MPU on a trial basis in the hope that you will have the money and the nerves to take legal action against it in order to ultimately gain legal certainty once the case has gone through the courts.
Let us now return to the special circumstances and try to list the most important risk factors that can lead to an MPU being ordered for a single instance of driving under the influence of cannabis.
It is reassuring to know that regular cannabis use in the past is no longer considered grounds for disqualification from driving and is therefore not taken into account as an additional factor. Of course, even if the driver's license authority becomes aware of it, membership in a cannabis cultivation association does not imply anything.
What is important, however, is whether incriminating factors can be inferred from the traffic history or the specific circumstances of the cannabis-related driving offense at the time, and whether the person concerned is able or willing to separate cannabis use and driving. Let's go through the individual points using examples.
α. Points of reference from the traffic history
Such points of reference may exist if, in addition to driving under the influence of cannabis, there are traffic violations or criminal offenses that indicate recklessness or a lack of self-control, such as aggressive behavior in traffic or driving without a license. Furthermore, it would be fatal if the person had been driving under the influence of alcohol prior to driving under the influence of cannabis or if a previous expert opinion had already required abstinence from cannabis.
β. Connecting factors based on special circumstances of drug-related driving
This would include a group of people who are particularly dependent on regularly driving a motor vehicle but are nevertheless unable to safely separate smoking cannabis and driving, such as drivers in emergency services, on call for the fire department, or in the THW (Federal Agency for Technical Relief).
However, the following two sub-points are probably more interesting, as they introduce the important distinction between the ability to separate and the willingness to separate, a distinction that is also relevant later in the MPU.
γ. Lack of ability to separate
This essentially refers to excessive cannabis use or an increased tolerance, which can be inferred from the values measured on the day of the offense. The driver's license authority assumes this with a certain degree of justification if a pure THC value of more than 15 ng/ml is present and there are (almost) no signs of impairment. A THC concentration of more than 8 ng/ml with a high THC carboxylic acid (= THC-COOH) level of more than 150 ng/ml would also be interpreted as an indication of impaired judgment. It is obvious that there must be no psychosis (paranoia or schizophrenia) resulting from smoking cannabis. Finally, attention has been drawn to bongs and “dabbing,” where significant amounts of pure THC, i.e., without tobacco, are inhaled. You are certainly not wrong in assuming that additional court rulings are needed to further narrow down the circumstances of a corresponding MPU order with reference to a lack of ability to separate.
δ. Lack of willingness to separate
Now, it may well be that the person concerned is perfectly capable of separating smoking cannabis and driving, but simply does not feel like doing so, i.e., they allow themselves to drive while under the influence of cannabis above the critical limit. Of course, it is difficult to prove such a “subjective fact” – as it is called in legal German – since no one can look into the mind of the person concerned and hardly anyone is stupid enough to tell the police that they drove even though they knew they were not allowed to.
Thus, a critical case arises, for example, when a driver has a passenger in the car who is in their care, when they have smoked cannabis in the morning even though they knew they had to drive to school or work afterwards. Another problematic variant is driving despite noticeable symptoms of intoxication, i.e., clear signs of impairment and, ultimately, proof that the driver drove immediately after consumption, i.e., deliberately failed to observe the required waiting period
The problem with such criteria is already apparent from the fact that the absence of impairment is considered questionable because it suggests a high level of alcohol tolerance, but then clear impairment is criticized. Of course, both effects can be made dependent on the level of THC measured, but such an assessment hangs by a thread. As with alcohol, the courts will hopefully have the final say.
However, please remember that the authorities, whose job it is to ensure road safety, must also consider specific risk factors when deciding whether a safe separation between smoking cannabis and driving can be assumed in the future after a drug-related driving offense, or whether it is reasonable to assume that further driving may occur.
As mentioned above, court decisions will provide greater clarity in the future. Since it is difficult for you as an outsider to gain insight into this area, and since only those who work in the field of driving aptitude are familiar with the specific practices of the authorities, I would like to repeat my offer of an initial telephone consultation and, if necessary, a consultation appointment.
Only by taking into account your personal file, i.e., your specific individual case, can the chances of passing an MPU and the associated time periods and documentation be assessed.
4. The right strategy: abstinence or separating cannabis use from driving?
Let's now turn to a question that is of particular interest to you. You know that you have to undergo an MPU if you have driven under the influence of cannabis twice, and you know that you can expect to have to undergo an MPU if you have driven under the influence once and there are additional factors or points of reference whose relevance has yet to be determined in your individual case. Let us therefore assume that the driver's license authority has ordered you to undergo an MPU for whatever reason and ask ourselves how you can pass it.
If your fitness to drive is in doubt due to cannabis dependence or abuse, it will only be restored once you have overcome your dependence or abuse in a stable manner. For rare cases of dependency, the criteria that have already proven effective for alcoholism apply here. After inpatient or outpatient withdrawal treatment, you must generally prove that you have been drug-free for one year. If you have already been abstinent for a longer period prior to therapy, this period can be reduced to up to 6 months. Without therapy, you will need a further three months, i.e. a total of 15 months of drug abstinence.
Of course, the question of when one can assume that cannabis abuse has been overcome is more interesting and much more common. And here there are now two options or strategies that you have been waiting a long time to evaluate. Is it sufficient to smoke cannabis in a controlled manner and separate smoking and driving, similar to the controlled drinking strategy discussed for alcohol in milder cases, or do you have to prove abstinence and, if so, for how long?
What makes this significant is that the driver's license authority no longer requires abstinence, as it did in the past, but instead asks a question about separation: “Is Mr/Ms X abusing cannabis? Is he/she able to safely separate cannabis use and driving a motor vehicle (ability to separate)?”
Of course, it is not decisive whether you were able to do so in the past, because driving under the influence of drugs proves the opposite. The decisive factor is whether you have changed your consumption to such an extent and also dealt with your drug problem to such an extent that a future separation can be assumed.
If we were to focus exclusively on this official question, the answer to our concern would be clear: Drivers who are addicted to cannabis must demonstrate a sufficiently long period of abstinence. Drivers who have “only” abused cannabis are allowed to separate, i.e., they only have to prove that they wait long enough after smoking cannabis to drive with less than 3.5 ng/ml.
In reality, however, the official hurdle is only one of many that you have to overcome. Regardless of this purely administrative issue, the MPU assessor has the freedom to decide what changes they require of you. Depending on the severity of the case, they can demand abstinence regardless of the questions asked by the driver's license authority.
In an attempt to gain clarity here, you will be able to consult many sources of information, forums, friends, lawyers, and anyone else you can think of. A degree of uncertainty will remain. Let us therefore take a closer look at the possibilities and risks.
The decisive factor for the assessment of a positive report are the so-called assessment criteria, which were published in their fourth edition in November 2022. They are still valid today, although publications by professional associations and specialist societies should also be consulted. Group D3 used to be responsible for assessing cannabis. This group included people who were considered to be at risk of drug abuse, i.e., potheads who occasionally tried other, harder drugs such as speed or ecstasy. “The client consumed cannabis frequently or habitually and/or only occasionally consumed a drug with a higher addictive potential, although they still had largely individual control over the amount and opportunity to consume.”[6]
These clients in group D3, i.e., the potheads, had overcome their drug abuse if they had completely stopped smoking pot and could prove this for six months, whereby four urine screenings or a 6 cm hair analysis was sufficient. However, if drug use had taken place over a long period of time (e.g., regular cannabis use over several years), one year of abstinence from drugs had to be proven, which meant six urine screenings or two hair analyses of 6 cm each.
The assessment criteria that had not yet been adapted to the new law initially referred exclusively to abstinence from drugs. Only for people who had smoked cannabis very rarely and exclusively was it conceivable to separate smoking cannabis from driving. Regular or habitual cannabis use (e.g., several times a week) was not compatible with separation.
And here, precisely at this point of reasonable separation, a new discussion arose, a new consideration for the MPU institutes, which attempted to incorporate the separation of cannabis use and driving more specifically, similar to alcohol, even before the publication of an updated edition of the assessment criteria.
In multiple training events, citing specialist texts, the MPU institutes then held out the possibility of separating cannabis use and driving in principle, but remained silent on the concrete implementation of this project. So can a cannabis user now separate the two or not?
In principle, it was clear that, based on the new legal situation and the assessment of experts, he was able to separate the two, which means that he was able to control his consumption and driving, but whether this was possible in individual cases = whether it would be possible in your case could only be decided in an MPU that looked at this individual case.
In milder cases, where an “inner bond” to THC was not yet pronounced, i.e., where consumption was irregular and in moderate doses, whatever that means, one might assume the ability to separate, similar to a client with a low blood alcohol level. In more serious cases, this was no longer justifiable, i.e., abstinence would be required, similar to alcohol.
But this is precisely where the changed legal situation of the driving license authorities hit the nail on the head. Hadn't we seen above that a minor case with just over one ng/ml of pure THC and a single instance of driving under the influence of drugs was no longer referred to an MPU? And wasn't a repeat offense or additional factors, including a significantly higher THC level, required to trigger the MPU requirement? And wouldn't this mean that the typical potheads who were required to undergo an MPU were no longer considered minor cases?
The change in the legal situation had created new groups of people who were required to undergo an MPU, and with them, the old abstinence criterion was reintroduced, quasi through the back door. No one can guarantee that you will be able to pass the MPU with a separation strategy, but no one can promise you that the separation strategy will be sufficient. This is because an expert could always assume, if the exploration revealed it, that you had not just smoked weed accidentally, but that you had done so frequently with questionable motives. As with alcohol, it did not help to downplay the matter and claim that you had hardly ever smoked weed. This is because the medical values indicated that this was extremely unlikely.
But it got even worse. As the authors of the assessment criteria announced at conferences and online events, it was to be expected that the changed legal situation and the legalization of THC would lead to citizens smoking cannabis more freely and thus be classified in the more serious drug group D2. This would apply to THC if the addiction to the drug is already so strong that it is no longer possible to control consumption. In this case, the criteria for abstinence that were actually reserved for drugs with a higher addictive potential, such as cocaine, methamphetamine, and, of course, opiates, must then be applied. In this case, clients who have not undergone addiction treatment—and this is likely to apply to almost all THC users, as outpatient or inpatient withdrawal treatment is not usually provided—i.e., clients who are classified as “self-healers”—are required to demonstrate 15 months of proven abstinence. You have understood correctly. If the expert considers you to be a heavy pot smoker in the context of their MPU assessment, you will have to prove not only twelve months of abstinence, but an additional three months. This would require two hair analyses of 6 cm each and one hair analysis of 3 cm, or seven urine screenings in 15 months, although this frequency still needs to be confirmed, i.e., you may first have to provide 12 months of evidence with six urine screenings and then another two or three for the remaining three months. Of course, there is no longer any question of separating smoking weed and driving.
Please also consider the dangers that additional alcohol consumption can entail. In principle, this group of people can be expected to consume alcohol if there are no indications of alcohol abuse. In this case, controlled alcohol consumption could be the goal. However, if the file contains evidence of driving with a blood alcohol level of more than 1.1 o/oo or if the psychologist's assessment reveals mixed consumption = simultaneous consumption of alcohol and cannabis or indications of a shift in addiction = switching to alcohol while abstaining from cannabis, then “abstinence from alcohol must be demonstrated by appropriate evidence for at least six months prior to the assessment.”[7]
To summarize: although the new legislative initiative has forced driving license authorities, professional associations, and experts to seriously consider separating cannabis use and driving, but experts in the MPU have reserved the right to assume a milder or more severe cannabis development depending on the history of consumption or psychological involvement with the drug, i.e., to allow this distinction in principle in the former case, but to revert to the requirement of abstinence in the latter, whereby aggravating circumstances were even taken into account.
It therefore makes sense for us to look at your case together during a consultation and then decide which strategy is right for you and what risk of failure in the MPU you are willing to take. Similar to alcohol, everything depends on your history, and similar to alcohol, abstinence is usually the stronger, safer option. This is because giving up cannabis brings about personal and social changes that can be presented positively in the MPU. Whether it is your newfound mental clarity and energy, your private life, your professional ambitions, or your general attitude toward life: all of this counts in the MPU in comparison to your previous life. Of course, those who consume cannabis in a controlled manner can also claim such positive changes, but I don't need to tell you that this is more sustainable with abstinence, a fact that you may have already noticed yourself when observing your friends.
5. Medical examination and proof of abstinence in the MPU
You probably already have a question on the tip of your tongue, and we would like to give it our full attention. As a cannabis user, do I need proof of abstinence, and if so, what kind of proof is required?
In fact, the answer to this question is more complex than one might expect, because it depends a) on the expert's assessment of the severity of the case, b) on whether other psychoactive substances were consumed in addition to cannabis (albeit possibly to a lesser extent), c) the questions asked by the authorities, and d) finally, the strategy for dealing with cannabis that the client is claiming.
A. D2: the “serious” cannabis case
This is the case if there has been massive cannabis abuse over a period of years with an internal addiction to the drug, or if, in addition to cannabis, drugs with a higher addictive potential are consumed not only sporadically but “repeatedly,” i.e., in particular cocaine, crack, methamphetamine, or even heroin. The use of unknown designer drugs or new psychoactive substances (NPS), i.e., synthetic laboratory products of unknown origin and effect, as well as the concomitant use of alcohol or medication to enhance the effects, also allows the expert to assume an advanced drug problem or a serious drug case.
As you already know, there is no longer a distinction between smoking cannabis and driving. In the MPU, everything remains the same, i.e., abstinence from all drugs must be proven, including a polytoxicological screening or a corresponding hair analysis, which, if alcohol abuse is known in the patient's history, includes documented abstinence from alcohol.
In concrete terms, this means that the client must demonstrate six months of abstinence from alcohol in addition to 15 months of abstinence from all drugs, including cannabis. If the question posed by the driver's license authority is not limited to drugs but explicitly includes alcohol, one year of abstinence from alcohol must be proven. It is important that, in this serious cannabis case, the proof of abstinence is not limited to cannabis.[8]
B. D3 – the “mild” cannabis case with additional recreational drug use
This group includes clients who mainly use cannabis but also occasionally use party drugs such as speed or ecstasy. The question of whether very rare additional cocaine use should still be classified as D3 or already as D2 must currently be considered open. The decisive factor here is the “inner bond” to cocaine, which means that the assessor asks about the reasons for consumption and then makes a decision. Until clarity has been established in the assessment criteria, it should be assumed that any cocaine consumption that goes beyond a few instances, which can be counted on one hand, will lead to classification in group D2.
If, on the other hand, case D3 applies, with mainly cannabis use and rare use of the two party drugs speed and/or MDMA mentioned above, the client must, interestingly, prove in the MPU that they have abstained from all psychoactive substances, including these two drugs, in short: prove that they have not taken any illegal drugs, including speed or ecstasy, for one year. However, with regard to cannabis, they can now decide whether they also want to abstain from this drug or whether they want to consume cannabis in a controlled manner in the future and separate smoking and driving. In the case of the former strategy, six months of cannabis abstinence will be required, which may be increased to one year in the case of long-term, intensive use. In the case of the latter strategy, such proof is not required. It must then only be proven that the person concerned has their consumption under control to such an extent that they are not under the influence of cannabis on the day of the MPU. A blood test showing a THC level of less than 1ng/ml is suitable for this purpose.
If the person concerned decides to abstain from cannabis, the advantages of which we have discussed above, they can prove their freedom from this substance either by four urine screenings in six months or six screenings in one year. Or they can provide this proof through a hair analysis, where they have the choice of testing only for THC at a low cost or for THC carboxylic acid right away. If the pure THC test is negative, proof of cannabis abstinence has been provided. However, if the THC test is positive, which is entirely possible if the individual has been in contact with cannabis users and passive consumption cannot be ruled out, it is possible to retest the hair for THC-COOH. Although this costs additional money, a negative result also proves abstinence.
C. D3 – the “mild” cannabis case without additional recreational drug use
a. Abstinence strategy
Finally, we come to the undoubtedly very common cannabis monoconument, i.e., group D3, with no knowledge of additional drug use. Here, too, in order to minimize the risk of a negative MPU, the client can opt for six months of abstinence, which – according to the criteria – may only require a hair analysis after three months or three screenings in four months in the case of very rare cannabis use in group D4, although such a mild case is unlikely to be found in the MPU. The variant you are familiar with is more likely to occur, whereby prolonged, intensive cannabis use requires proof of abstinence from this substance for one year. The evidence options described above also apply here. Proof is provided either through urine screenings or hair analysis, whereby a negative THC test is sufficient or a THC-COOH test, either alone or following a positive result in a pure THC test.
b. Disclosure of other drug use
You have accepted this confusing variety of possibilities without complaint and are now ready to learn about another complication before we deal with the separation strategy. What happens if the client admits to having used other psychoactive substances in an MPU that, based on the files, was only intended for cannabis and was only ordered by the driver's license authority with a question about cannabis?
In this case, the assessor may decide whether to use this information to place the client in a more severe diagnostic group. In the case of more than very rare cocaine use, this would be the above-mentioned group A. D2, and in the case of very rare cocaine use and the use of party drugs such as XTC or speed, this would be the above-mentioned group B. D3.
However, he will not explore this further in the MPU, but will limit himself to informing the driver's license office that there are “incidental” indications of the use of other psychoactive substances. The driver's license office must then decide whether to use this information to order a new, extended MPU.
But what verdict will the expert now deliver in the first MPU applicable to cannabis? Our expert is clearly faced with a dilemma here between the narrow, cannabis-specific official question he is bound to ask in the MPU and the broader use of consumption data on other drugs. How he resolves this dilemma (in the initial assessment) is a question for others to answer. The assessment criteria do not provide an answer. A new edition is planned for fall 2025 or later. Since the expert is not allowed to explore the additional consumption in detail or request proof of abstinence beyond cannabis, it is possible that the client will receive a positive assessment with sufficient proof of abstinence from cannabis.
This would be possible, for example, if the additional drugs were not the main focus, if there was no inner attachment to these drugs or no chain of consumption with cannabis, and if the client had excellently dealt with their drug history. However, if it becomes apparent during the interview – which should not actually focus on these additional drugs – that these requirements are not met, the assessment would be negative for psychological reasons, as the overall findings do not indicate that the client has sufficiently overcome their problems.[9]
c. Aggravating diagnosis D2 (or D1) in the MPU
The matter also becomes complicated if the client enters the MPU as a single user with an official inquiry limited to cannabis and it then turns out that he or she should be classified in group D2 due to heavy cannabis use. In this case, abstinence from cannabis for 15 months may be sufficient if the client can demonstrate in the psychological interview, as previously requested, that they understand and have overcome their previous abuse. However, if physical dependence on cannabis is diagnosed, which is rare, the assessor is likely to require abstinence from all other drugs, as safety in all respects is sought here due to the high potential for addiction. As you already know, this also includes abstinence from alcohol for three months if there are indications of previous alcohol abuse, without additional official alcohol questioning for six months and with corresponding questioning for one year.
d. Recommendation for the correct proof of abstinence
The whole situation is highly unsatisfactory, as very few people are aware of the official requirements at the time they begin their period of abstinence, and no one can know for sure how their own consumption behavior will be assessed in the MPU. This leads to the recommendation that, as a monoconuser of cannabis, one should only limit oneself to proof of abstinence from cannabis if one's past consumption has been moderate and limited in time. If, on the other hand, there is more intensive cannabis use with strong motives rooted in personality or life history, then – as long as the assessment criteria do not provide clear guidelines – it is advisable to undergo a 15-month polytoxicological test, which is only slightly more expensive, as this is the safest option. In cases of physical dependence, this is probably mandatory. And in the case of any kind of additional use of other party drugs, abstinence from these drugs for a period of one year will be required, although in milder cases of cannabis use, a reduction to six months or even a separation of cannabis use and driving is conceivable.[10]
e. Separation strategy
We will now take a closer look at this when we return to the second strategic option for a cannabis monoconuser, namely asserting controlled consumption and separating cannabis use from driving. In this case, proof of abstinence is not necessary. The doctor in the MPU will no longer request this. The psychologist must then assess whether the person concerned is able or willing to separate cannabis use and driving, whether the new behavior is stable, and whether appropriate strategies are known and have been tried and tested. In contrast to the previous legal situation, the decisive factor is that occasional or even regular consumption does not in itself exclude fitness to drive; rather, the decisive factor is whether the client is able to consume in a controlled manner and reliably separate the two activities. A credible change in consumption behavior and knowledge of the waiting periods required before driving are paramount, whereby the sobriety test already introduced above, involving a blood sample with less than 1 ng/ml, also applies here.
However, please keep in mind the truth that I have repeatedly pointed out to you. It is not you who decides which strategy will lead to a positive assessment, but the assessor. If he is of the opinion that you cannot be expected to control your consumption, demonstrate a willingness to adapt socially or, as it is called, “competence to change,” then the report will be negative, even if you claim behavior that is actually permitted by law, namely separating smoking cannabis and driving.
This is because, as with alcohol, although consumption is legal, it cannot be demanded that you separate alcohol and driving on the one hand, and smoking cannabis and driving on the other. You therefore have no legal right to this strategy and are at the mercy of the expert's assessment. I would be happy to discuss the chances of an assessment using this strategy with you once I am familiar with your case. However, it has become clear that absolute certainty cannot be promised here and that clients who depend on their driving license and want to minimize the risk of a negative assessment are better off with the abstinence strategy. This is because everything that counts in the assessment—distancing yourself from the wrong circle of friends, giving up the dominance of cannabis in your life, the new energy you gain without this drug, the mental clarity, in short: the tidiness in your life—is much easier to convey with abstinence.
f. Criteria for the correct implementation of the separation strategy
Finally, let's take a look at what a strategy for controlled consumption or separating cannabis use and driving might look like. Because, of course, I don't want to leave you in the lurch in such a case either.
The literature has developed strategies for successful separation and has also dealt with reasonable waiting periods after cannabis use.
α. Lower-Risk Cannabis Use Guidelines (LRCUG)
An international panel of experts led by B. Fischer has published several promising strategies for low-risk cannabis use. You can find this information on the website of the Canadian Ministry of Health or in the PDF file, which you can download here.
I would be happy to summarize for you what assessment institutes and professional associations have made of this. Take the criteria into consideration and then decide for yourself or in consultation with me how realistic their implementation is.
In order to reap the benefits of low-risk cannabis use, you should only start smoking cannabis after puberty, which means that you should only smoke cannabis as an adult, thus fulfilling the German legality criteria, which, as is well known, prohibit consumption before the age of 18. The original Canadian publication variably cites a period of 16 to 20 years as a possible time frame for first use.
Furthermore, you should choose cannabis products with a low THC content and a high CBD content (= cannabidiol) and avoid highly potent THC extracts, as these can more easily lead to psychological problems or promote addiction. Synthetic cannabis products such as K2 or Spice are taboo. You should also use legally purchased, quality-tested products and avoid forms of consumption that are harmful to your health. This means completely refraining from smoking THC, as this damages the lungs, and switching to a vaporizer or e-cigarette instead, or consuming edible forms of cannabis, bearing in mind that the delayed reception = absorption of the substance and therefore the longer after-effects.
If you do decide to smoke THC, it is recommended that you do not inhale deeply and then hold your breath to increase the effect. Inhalation methods that are probably only known to experienced users, such as the Valsalva maneuver (forced exhalation against resistance) and its reversal, the so-called Müller maneuver (deep inhalation through a device with increased air resistance), are also not recommended.
Since frequent and intensive cannabis use is most likely to lead to health problems, you should only smoke cannabis occasionally, i.e. one day a week or at the weekend, or even less frequently.
We will discuss waiting times after smoking cannabis below when we look at the legal situation in Germany and how it relates to the potential impairment of driving ability caused by cannabis. The Canadian expert team recommends refraining from driving or operating machinery that requires a high degree of attention and psychomotor control for at least six hours. As we will see, this period is adapted to the previously recommended infrequent consumption of moderate amounts of cannabis.
It is certainly not a mistake to take into account the family history of the potential cannabis user and their state of health. People with a history of psychosis or substance abuse in their private lives and, of course, pregnant women should refrain from using cannabis altogether.
Even though scientific research into cannabis is still in its infancy, i.e., its former illegality had hampered relevant projects, it can already be assumed that a combination of the above-mentioned risk factors increases the dangers associated with cannabis use and should therefore be avoided.
We have presented the criteria for low-risk consumption proposed by the Canadian team in full, as they have been discussed in detail in the German literature and can therefore serve as a basis for MPU institutes, and also to present a possible range of behaviors for controlled cannabis use and separation of cannabis use and driving.
β. Assessment of the Canadian model of low-risk cannabis use
Judge for yourself whether its implementation is realistic or whether these proposals only exist on paper. You know your past behavior and that of your friends. You know how you were able to increase the effect of smoking and you know what quantities and frequency were desirable, based on the tolerance increase that occurs with every drug, to get you or your friends into that pleasant flow that made cannabis so attractive. Is it likely that you will give up these patterns and quantities of consumption, i.e., return to a permanent reduction after what scientists have declared to be abusive consumption, or had you and your friends already reached a point where it was just a matter of rationalizing your own consumption, lie to yourselves about the importance cannabis had already gained in your lives, and postpone the moment of decision that you sensed would require you to give it up?
Similar to alcohol, reducing consumption and separating the critical substance from driving is only suitable for a certain group of moderate users, and similar to alcohol, many of those affected will prefer to give up the addictive substance altogether before even considering a project of controlled consumption. Nevertheless, it is to be expected that experts will rely on these behavioral strategies if abstinence is not the goal of the individual's departure from their previous abuse = change.
These strategies developed by our Canadian expert group can certainly be supplemented, i.e., your prevention can include the motives for consumption, the occasions for consumption, the social context in which you consume, and a differentiated knowledge of potential relapse situations or, as they are called, “slippery slopes” that jeopardize your control. I would be happy to work with you individually to identify these in a training session. These pages provide you with sufficient information about the dangers of this approach, even if it is presented in a highly skilled manner. This is because it is the assessor who decides whether your strategy is credible and viable, and therefore whether you can be expected not only to know it, but also to implement it in the context of any personal or social situations that may tempt you. As is well known, there is always a risk of relapse, even in the case of abstinence, but since this is accompanied by an inner distancing from the drug and a corresponding strength of will, it is considered to be lower. It is therefore understandable that the Canadian model warns against the individual risks of any cannabis use and succinctly states: “The most effective way to avoid the risks of cannabis use is to abstain from use.”[11]
g. Recommendation
I think that we are no longer resisting the idea that the most effective way to obtain a positive assessment is abstinence. I recommend this path not only so that you have the best possible chance of getting your driver's license. I also recommend it to you in order to initiate an important personal experience that will enrich you as a person. Regardless of whether you decide to live without cannabis permanently or want to smoke again later, if you have smoked regularly for a certain period of time – which is the case for the vast majority of people who ask me for advice on cannabis – abstinence will allow you to take a step that will open up new realms of experience. Alone with yourself, your body, and your soul, you will realize that you can trust yourself again and that you are stronger than a drug that once manipulated you and allowed you to play a (too) important role in your life.
Many of my clients experience the rehabilitation phase as liberation, as an important part of a self-determined life, regardless of whether they want to continue on this path in the long term or even permanently. Treat yourself to this experience of abstinence and return to the experience you had before your cannabis period, when you were a young person without this drug. By experiencing life without drugs, you can also regain the mental freedom to decide responsibly whether and, if so, in what form you want to smoke cannabis and how you want your life to be in the future. The freedom to decide remains yours, as does the opportunity to gain important new experiences.
6. Waiting periods after cannabis use and the legal situation in Germany
Low-risk consumption is only the first part of a successful avoidance strategy. Now it is up to you to demonstrate that you will wait long enough before driving, i.e., that you know and observe the relevant waiting periods. I am happy to provide you with some tips here as well.
In mid-2024, the German Society for Traffic Psychology and Traffic Medicine issued recommendations for sufficient waiting times for participating in traffic after consuming cannabis, which we are happy to endorse here. It goes without saying that precise information is not possible, as everything depends on the quality, quantity, and frequency of consumption, and in particular, the dose of cannabis consumed cannot be determined with certainty. Furthermore, the logarithmic breakdown of this drug makes reliable calculation highly complex, which carries the risk of misjudgment if there is a slight deviation from the critical parameters.
In order to take into account the dependence of THC detectability not only on the last consumption and the amount consumed, but also on consumption habits, the professional association issues different recommendations for occasional and regular cannabis use.
A. Occasional use
This is the case when there are several days between individual cannabis use, when only moderate amounts are consumed and when cannabis is only smoked once per occasion, which specifically means that for a cannabis product with a 10% active ingredient content, the consumption amount does not exceed 0.25g of cannabis or 25mg of THC. In this case, the THC level drops to 0 before cannabis is consumed again. It can also be assumed that there is no psychological dependence, as the individual was strong enough to take a break.
With occasional use, it can be expected that the THC level in the blood serum will fall below 1 ng/ml after 6–7 hours, and after 3–5 hours, the new limit value of 3.5 ng/ml should be below the threshold.
However, as various factors play a role, such as the density of the pack, the temperature of the joint, the depth of inhalation, and individual differences in biological degradation rates, it is recommended to wait 12 hours before driving in order to be “on the safe side.”
However, if you do not know the active ingredient content of the cannabis, or if you did not limit yourself to one joint or the moderate consumption mentioned above, or if you consumed the cannabis orally, for example in a cookie, which delays absorption, as recommended for health reasons, you should wait 24 hours after consumption before considering driving a car.
B. Regular consumption
This is the case when cannabis is consumed several times a week, but not yet daily. This can lead to a build-up in the body and reabsorption, which complicates the determination of safe waiting times. If moderate consumption can be assumed, the THC level should be below 3.5 ng/ml after 3 to 5 days. “In the case of high consumption on a daily or multiple daily basis, participation in traffic is generally ruled out and should only be considered again after a longer period of abstinence lasting several weeks.”[12]
So much for the required waiting times after cannabis use. You are now aware of the particular risks associated with taking this drug and can decide whether you want to pursue cannabis use in any form and separate smoking cannabis from driving.
7. Summary
The revision of the Cannabis Act has brought about a radical and irrevocable change in the assessment of this drug and its relationship to driving ability. Cannabis is no longer a narcotic, and its occasional or even regular use does not in itself affect a person's fitness to drive. This presents a challenge to the authorities, professional associations, and MPU institutes to find new answers that reconcile citizens' freedom with the need for road safety.
The law has set more or less strict limits on how you can legally obtain cannabis. With regard to fitness to drive, pure consumption only becomes a problem in rare cases of physical cannabis dependence. Otherwise, two drives with a THC level of over 3.5 ng/ml are usually required to trigger an MPU. Nevertheless, there are a number of controversial additional facts or indications that can trigger an MPU even after a single drive. Their implementation depends on the authority, or more precisely, on the internal guidelines followed by your case worker.
It is likely to take a considerable amount of time, i.e., several years, before these criteria are formulated in a legally binding manner through court rulings and other additions. With regard to consumption, you have two possible strategies in an MPU, if one is ordered. You can prove abstinence or claim moderate consumption with a separation between smoking cannabis and driving. Of course, the likelihood of success of each of these strategies depends on your history, i.e., your driving record, on the one hand, and the expert's assessment of the severity of your case on the other. Ultimately, a combination of both factors will determine which strategy you use to keep or regain your driver's license.
In all cases, the abstinence strategy is likely to be the safer route to obtaining a driver's license, although depending on whether you were a moderate or heavy pot smoker, whether you smoked pot for a relatively short or long period of time, and whether other drugs, including alcohol, were involved, periods of abstinence ranging from 6 months to a year, or even 15 months, may be discussed.[13] Only consultation with an experienced traffic psychologist can provide you with empirical values, which are nevertheless associated with a residual risk in the case of shorter periods of abstinence.
The currently heated debate about separating cannabis use and driving in cases of moderate consumption was certainly a significant step toward legal equality between alcohol and cannabis, and thus toward the decriminalization of the latter drug. However, its implementation depends on a number of factors that are not always met and cannot be easily asserted in the MPU. Similar to alcohol, an expert can require you to abstain not only in the case of physical or psychological dependence, but also in the case of mere abuse, even though the consumption of both drugs is legal. Criteria that you cannot influence will play a role here, such as your inner attachment to the drug, the frequency and quantity of consumption in the past, and the motives for consumption, as well as the assessment of your character, your willpower, and your ambitions to implement the new measures. The question is therefore whether you can consume cannabis in a controlled manner and then refrain from driving, and whether you want to do so.
Only the MPU assessor can determine how to answer these questions in your case, i.e., whether it is still reasonable to separate cannabis use from driving in your case given your moderate consumption, or whether abstinence is necessary. It is therefore up to you to decide which avoidance strategy you feel confident in and what residual risk you are willing to accept. If you depend on your driver's license and want to minimize the risk of a negative assessment, you should opt for abstinence and clarify how long this will be necessary in your case. I would be happy to help you with this. If, after honest self-reflection, you believe that you are a mild cannabis case, for example, someone who has smoked cannabis moderately over a short period of time, who enjoyed cannabis without really needing it, and who also had a wide range of interests and contacts outside of cannabis use, separating cannabis use from driving may be an option.
All of this is certainly not easy for an outsider to judge. Therefore, you should consult a qualified traffic psychologist. Tell them honestly about your past and work with them to develop a plan for getting your driver's license back. Always remember that your driver's license is only one part of your life. Other aspects may come into play if you reduce or stop your cannabis use altogether. By giving up this fascinating drug, either completely or to a lesser extent, you will open up new possibilities for yourself. You will perceive yourself and your friends differently and you will realign your life in your own way. In short, you will surprise yourself and benefit most from the change. I would be happy to accompany you on this journey as your advisor, not to judge you morally, but to help you understand yourself and succeed in the MPU.
8. Medical cannabis
Hardly any other topic has heated up the debate as much as the question of how medical cannabis should be assessed in terms of driving ability, and hardly any other topic has left so many questions unanswered. Let's try to gain at least an overview and find out under what circumstances this path can or should be taken and when it is not advisable.
The issue is complicated by the fact that there are genuine and bogus cases of medical cannabis use. Genuine cases involve a clear diagnosis, a sensible medical prescription, and credible, considered use. In non-genuine cases, the diagnosis is fabricated or obtained from the internet as desired; the prescription is intended to make it easier and cheaper to obtain cannabis, which is consumed for pleasure and could supplement cannabis obtained by other means.
No one wants to accuse you of belonging to the group of people who play with the possibility of medically prescribed cannabis without actually being ill, but no one will rule out the possibility of such abuse in an MPU.
It is therefore important for you to know how medical cannabis is assessed by authorities and experts and what requirements must be met. As with all topics covered on this website, I am happy to provide you with my individual assessment of your situation. Since the official use of medical cannabis involves a significant legal intervention in your personal status, you should carefully consider whether you want to go down this path or whether you have to do so for health reasons, or whether there is an easier, legal way to obtain cannabis. The medical use of cannabis also raises complex questions, such as the legal limit for driving under the influence of the drug or your knowledge of when and in what dosage you are allowed to take which of the prescribed products without endangering others. So let's take a look at the old and new legal situation.
A. Old and new legal situation
In the past, lawmakers had already granted the possibility of legally consuming cannabis as a medicine and then, under certain circumstances, participating in road traffic. However, this fundamental opening up of consumption and participation in road traffic was subject to strict restrictions that could not be met in many cases.
It was trivial that applicants for medical use of our drug had to provide a reliable diagnosis, a clear prescription, and demonstrate reliable consumption behavior or present this in the assessment. Less trivial was the fact that the person concerned was only granted the privilege of consumption if they had exhausted all other therapeutic options. This was called the “ultima ratio principle,” and it was understood—though unspoken—that this created a decisive argument against the use of cannabis as a medicine. In particular, doctors and psychologists at the MPU institutes, which were responsible for ensuring compliance with this principle, had enormous power to reject the medical use of cannabis, since hardly anyone had tried all the usual therapies without success before cannabis came into play. Of course, there were clients like this, and of course there were positive expert opinions for them, but the implementation of this principle was subject to considerable fluctuations. For example, one driver's license authority refused to issue a driver's license despite a positive medical opinion, while others followed the medical recommendation without complaint, and MPU institutes also varied in their strictness in assessing these cases.
B. Medication privilege and waiver of the ultima ratio principle
All this has now been overturned by the new legislation, because, on the one hand, medication privilege has been established and, on the other hand, the ultima ratio principle has been abolished. Every citizen is therefore free to take the medication prescribed by their doctor. It is also no longer necessary to prove that other therapies have failed.
C. Lack of a limit value in road traffic
Furthermore, the legislature has failed to set an upper limit for the permitted participation of medical cannabis patients in road traffic. You heard right. While cannabis consumed legally in leisure time was only considered safe for driving below the limit of 3.5 ng/ml, in the case of medical cannabis, the intended use and proof that, regardless of the limit, the patient's reaction time was such that there was no impairment of driving ability was taken into account.
In concrete terms, this means that a citizen whose diagnosis and prescription meet the necessary criteria of medical integrity may legally drive with a value higher than 3.5 ng/ml if the circumstances of consumption have been clarified and sufficient reaction times are ensured.
D. Specialist medical opinion and reaction time
This is ensured by a specialist medical opinion (or, in certain cases, an MPU, which involves a psychologist in addition to a doctor). The client is required to take the cannabis prescribed by the doctor as directed in the days prior to the examination. They are then given the test battery while under medication. If they react quickly enough or carefully enough = meet the minimum performance requirements, it can be reasonably assumed that they also have the necessary ability to drive a car.
E. Driving under the influence of cannabis and self-therapy in the past
The case becomes interesting when, in addition to the application for medical cannabis, there is a previous case of illegal driving under the influence of cannabis and the client claims that he also used cannabis at that time to treat his illness himself, but now wants to go down the path of correct prescription.
Let's take a closer look at how the driver's license authority and experts from an MPU institute react in such a case and then examine which path is the right one for you. As before, however, I would like to start with a warning. In view of the fact that much remains unclear, i.e., the practices of the authorities and experts are still in their infancy under the new legal situation, we must not lose sight of the provisional nature of this assessment and the need to closely monitor developments. What applies today may be obsolete tomorrow. Only close contact with a traffic psychologist can ensure that you are on the right track. And only a phone call or two to the authorities or your assessment institute can ensure that you do not walk into a trap or that you meet the criteria for legitimate use of medical cannabis (even if you have a history of illegal use or have driven while under the influence).
Q. The standard case: Prescription of medical cannabis without previous problems with driving ability
First, let's assume that not every medically prescribed use of cannabis is reported to the authorities. This is because doctors and clinics are bound by confidentiality, and the police will only become aware of your case if you show signs of impairment while driving. In concrete terms, this means that the person concerned either keeps a patient ID card or a prescription in the glove compartment and informs the police officer that they are a cannabis patient. They are then often allowed to continue driving, as it can be assumed that the cannabis has been taken as intended and does not affect their behavior. In the opinion of some lawyers, there is no reasonable initial suspicion of drug driving in this case, and a blood sample is also inadmissible. And indeed, the Bavarian Administrative Court (BayVGH) has pointed out in a recent ruling that this practice is standard. Only in the event of symptoms of impairment is a blood sample taken, i.e., a medical value that can be passed on to the driver's license authority.[14]
a. Hearing
If the driver's license authority learns that a driver has participated in road traffic under the influence of cannabis, it will, since it usually does not have detailed knowledge of the incident and cannot know what type of consumption is involved, send a so-called hearing in which the person concerned is asked to comment on the facts.
Let us assume that the person named informs the authority in this hearing that they are a medical cannabis patient and therefore legitimately drove a car under the medically prescribed, intended amount of cannabis.
b. Questionnaire and certificates from the attending physician
In accordance with the principle of proportionality and the least necessary interference with the rights of citizens, the authorities will ask the client or the attending physician to answer questions about the illness and prescription and request certificates.
If these documents are available, the authorities could, in principle, close the case as they would for other illnesses. However, since driving under the influence of drugs is a matter of record, they will generally require the person concerned to submit a specialist medical report from a recognized assessment center.
c. Specialist medical report
In this assessment, you will have to answer the MPU institute's doctor's questions in detail, i.e., you will have to prove in a differentiated manner that you not only have an illness that can be treated effectively with cannabis or that you obtained the prescription legally, but also that you are sufficiently informed to take the medication as intended. The assessment institute often sends the person concerned a questionnaire in advance, which they can then fill out in consultation with the prescribing doctor. If you are at this stage of the official procedure, please feel free to call me to arrange an appointment for a consultation. I have developed my own detailed questionnaire on medical cannabis, which contains the questions you will be asked on the day of the specialist assessment, and I would be happy to go through your answers with you. If everything is in order, you should meet the requirements for a positive assessment.
d. Long-term medication and medication on demand
Of course, it is also important to determine whether you require long-term or as-needed medication, i.e., whether you, as a pain patient, only take cannabis in acute cases and can then wait 6 to 12 hours before driving, in accordance with the above-mentioned values, or whether you need to take cannabis daily. A combination of both dosages is also possible, e.g., a lighter dosage as a long-term medication and a stronger dosage as an acute medication. In this case, it would be useful to consult with your treating physician to determine when you can drive again after taking the acute medication.
If separating cannabis use and driving is not really an option due to long-term medication, you should take the medication exactly as prescribed on the day and in the days leading up to the specialist assessment. The doctor or psychologist would then ask you to sit at the test device, which is a type of computer that checks your reaction time. Similar to other medications, you will be considered fit to drive under the influence of cannabis if you achieve sufficient results in this performance test.
The Munich Administrative Court[15] has formulated the requirements for driving while under long-term medical cannabis treatment in accordance with the assessment criteria developed by professional associations. As with legally acquired cannabis, regular use of our drug as a medication does not in itself preclude fitness to drive, but it is subject to clear conditions.
First, there must be a plausible diagnosis and an indication for prescribing the medication based on this diagnosis, both of which are the responsibility of the treating physician and may not be reviewed or questioned in an assessment. Then, the cannabis must be taken reliably according to the doctor's prescription or, as they say, “as intended,” which means that the person doesn't increase the dose or use legal street cannabis at the same time as medical cannabis (see below). Furthermore, no lasting effect of THC on performance is to be expected, such as a decline in fitness due to fatigue or exhaustion. We have already seen above that this is ensured by sufficient results on the reaction test device. Then again, the underlying disease itself or its symptoms do not have any significant impact on traffic safety, i.e., there are no sudden episodes of clouding of consciousness or a sudden decline in physical and mental performance. Finally, the patient is able to refrain from participating in road traffic in risky situations in which they feel temporarily impaired, for example due to higher medication requirements, a more acute effect of the disease, or a decrease in the effect of the medication. This requires appropriate information from the physician and careful self-observation adapted to the situation.[16]
Further aspects, such as the necessary understanding of the illness, regular care and consultation with the treating physician if changes in symptoms or medication effects occur, and the need for a controlled adjustment phase of the medication, which ultimately transitions into a stable dosage phase, are discussed in the questionnaire I have prepared for you. In it, we can go through your individual case in detail and work out the answers that count in the assessment.
e. Medical cannabis and alcohol
With regard to alcohol, the assessment criteria and the most recent ruling of the Munich Administrative Court[17] contain a restriction clause that is likely to remain in force until further notice. It states that the combined use of medical cannabis and alcohol is considered abusive consumption due to the expected enhancement of the effects of THC by alcohol and therefore excludes fitness to drive. Interestingly, the decisive factor here is not the simultaneous consumption, i.e., the temporal aspect, but the combined intoxicating effect = the effect-related aspect. This apparently means that if you are taking medication on a long-term basis, i.e., the THC level does not drop to 0, any alcohol consumption is taboo.
If, on the other hand, cannabis is taken exclusively as medication when needed, i.e., you observe the waiting periods listed above, controlled alcohol consumption may be conceivable. In this case, you would not only wait to consume alcohol until you are no longer under the influence of THC and vice versa. You would also wait to drive until you no longer have either substance in your blood. Unfortunately, neither the assessment criteria nor the Munich Administrative Court have satisfactorily addressed this aspect of controlled alcohol consumption in cases of exclusive medication for medical purposes, so I recommend that you abstain from alcohol in all cases. Proof of abstinence for three months prior to the assessment is considered sufficient if there are no other indications of alcohol abuse.[18]
G. The complicated case: Prescribing medical cannabis after previous illegal cannabis use while driving, with or without the intention of self-medication
Let us now return to the case of a prescription for medical cannabis after previous illegal cannabis driving, which may be of particular interest to you.
a. Hearing, specialist medical opinion, and MPU
In such a case, the authorities will initially react in a similar way to the first case, i.e., after the mandatory hearing, they will obtain a medical opinion on the background to your request. However, even if the medical opinion is positive, they will usually order an MPU as well. This is because, in addition to the question of whether you are ill and are allowed to take the medication legitimately, there is also the question of why you drove under the influence of cannabis illegally at the time and how you can avoid doing so in the future.
Let's not kid ourselves. In such a case, without having to tell you so directly, the authorities will assume that the medical cannabis diagnosis is only a pretext and that you either want to obtain cannabis cheaply on prescription or even want to drive legally under a higher limit. After all, apart from a police investigation, such as a search of your home to find non-medical cannabis, how can they determine whether you took the medication or recreational cannabis? The blood value relevant here does not yet allow the origin of the cannabis to be determined.[19]
Everything therefore depends on the MPU and the assessment of the psychologist or doctor, who must decide whether your case is comprehensible and whether it is possible for you to transition from (possibly former illegal) recreational use to legal, medically prescribed use.
b. Special case: recreational use and medical use
Let us briefly examine how a case is assessed that involves both forms of use. The detailed court ruling of the Bavarian Administrative Court (BayVGH) already cited above is available, which ruled against the applicant in the case of such mixed use. It is significant that the use of cannabis outside of a medical prescription can be considered misuse of a psychoactive drug and that the simultaneous use of recreational and medicinal cannabis is prohibited due to the associated lack of restrictions or controls on consumption. but in any case triggers the case law on recreational cannabis use, since standard cannabis use now exists per se, for which strict rules on separating cannabis use and driving apply, such as the limit of 3.5 ng/ml.
Now that you know that you may only use cannabis as intended and that any deviation from this can be fatal, let's return to the question of how the driver's license authority and the MPU institute view your case.
c. Requirements for a positive MPU assessment
Although the authorities may speculate about the reasons behind your medicinal cannabis use, they must base their decision on whether to grant you a driver's license on an MPU assessment. Two aspects will be decisive in this assessment. Firstly, have you overcome your previous (illegal) use, i.e., have you fulfilled all the requirements that are also imposed on a standard user in this regard, which means that you must provide a detailed account of your drug history, your consumption habits, the motives for your consumption, as well as aspects of the risk of relapse and your plans to avoid it? Is the transition from recreational use to medical use biographically credible and toxicologically comprehensible?
Of course, if your illness can be proven to have occurred during the period of abuse, some form of self-prescription may be considered, but it is clear that standard prescriptions that can be downloaded cheaply from the internet without knowledge of the qualifications of the prescribing doctor are not acceptable. This is because if your story is fabricated or contrived and the illness and the need for a prescription are not reasonable, the expert can assess the case negatively. It is the psychologist's prerogative to evaluate all the arguments you present from a professional standpoint.
Have you come to terms with your past abuse? Do you know the motives for your previous use and the dangers of switching to the medication? Did you have a psychological dependence, an increased tolerance, or a social susceptibility that would prevent you from using the substance in a controlled manner? Have you distanced yourself from your former life, or is there a risk that you will progress from medical cannabis to uncontrolled cannabis abuse?
d. The expert's decision-making privilege and the problem of credibility
Arguments of this nature are complex in both presentation and assessment. If the expert exercises his decision-making privilege to the effect that he considers your transition from recreational to medical cannabis to be unstable, the MPU, which must evaluate both aspects, will lead to a negative overall assessment. Of course, such an expert opinion must be justified, but hardly anyone would doubt that a trained psychologist and doctor can come up with the right arguments.
It is not even a question of whether you will be viewed negatively in the MPU per se if you fall into the aforementioned group. The point is that the legislator requires the expert to answer the question of road safety to the best of their knowledge and belief. Anyone who is honestly and plausibly dependent on medical cannabis also has the right to live with it and drive in accordance with safety regulations. Anyone who wants to strategically improve their own recreational consumption through a fabricated diagnosis and prescription runs the risk of failing. Psychologists are trained to check the credibility of people's statements. They use body language, coherence, and overall demeanor to assess a case and, if they are experienced, they do not rely solely on what is said verbally. So even if you say the “right” thing, there is no guarantee that this will be enough for a positive assessment.
e. Effects of a medical cannabis diagnosis
Of course, there are other arguments against a purely strategic approach to medical cannabis in such cases. Professional colleagues repeatedly point out that your file will contain an entry with various consequences that are not always predictable. As a medical cannabis patient, you are ill. You may also have to disclose this information to third parties, such as insurance companies or your employer. As a pilot or security employee, you must meet high health requirements that may not be compatible with any type of medication.
H. My recommendation
Therefore, follow my simple advice. If you are healthy and want to smoke cannabis, take the legal route granted to you by society, which requires you to smoke cannabis with caution, separate smoking and driving, and thus not pose a danger to third parties. In this case, you will not be driving under the influence of cannabis, which means you will not come into contact with the criminal law of the courts and the driving license authorities.
If you need cannabis to make your life more livable; if you want to take it in a clearly defined manner agreed with your doctor in order to experience the undisputed medical effects of this fascinating substance in a different way, in the sense of alleviating your symptoms, then do not hesitate to exercise this right. Then, and only then, will you find in me a companion who will help you pass the medical examination, and you will also encounter employees at your driver's license authority who will grant you this privilege, because you will have long since submitted documents and evidence that make your case transparent. I would be happy to support you as a cannabis patient on your well-deserved path to obtaining a driver's license.
- [1]Federal Ministry of Health: Questions and answers about the Cannabis Act:
https://www.bundesgesundheitsministerium.de/themen/cannabis/faq-cannabisgesetz.html. - [2]No specific active ingredient content has been specified for persons aged 21 and over. Prior to this age, cannabis sold to “adolescents” may not “exceed a THC content of 10 percent” (CanG § 19 (3)).
- [3]See Federal Law Gazette 2024 I No. 109 of March 27, 2024 – Article 3: Amendment to the Narcotics Act or Federal Institute for Drugs and Medical Devices. Federal Opium Agency. Medical cannabis: “Cannabis is removed from the scope of the Narcotics Act.” (https://www.bfarm.de/DE/Bundesopiumstelle/Medizinisches-Cannabis/_node.html).
- [4]The relevant Section 24c of the Road Traffic Act (StVG) does not specify a limit for cannabis, i.e., driving under the influence of THC is prohibited with the exception of the medical cannabis clause. After a limit of 1 ng/ml for novice drivers was discussed for some time, the Federal Ministry of Transport (BMV) clarified in an article dated August 21, 2024 (“Legal THC limit in road traffic announced”) that both alcohol and cannabis are completely prohibited for novice drivers and young drivers up to the age of 21.
- [5]See both quotations in: FEV §13a, 2.a) and d).
- [6]Brenner-Hartmann et al. (2022). Assessment criteria. Judgment formation in driving aptitude assessments. 4th edition. Bonn: Kirschbaum: p. 170 (criterion D 3.1 K).
- [7]See assessment criteria: 166. This applies in cases where the driver's license authority chooses to ask questions about drugs only. If, due to drunk driving, it additionally insists on an alcohol question in the MPU order, you must prove one year of alcohol abstinence.
- [8]We are tacitly assuming here that the authority has chosen a comprehensive question covering all drugs. We will examine the special case of a question relating solely to cannabis and what this means for the required proof of abstinence in more detail below.
- [9]It should also be borne in mind that the assessor is still permitted to ask about addiction to other drugs, which means that these substances will then be addressed in the assessment after all. It could be argued that this is not about past use, which is off limits, but about future use, but the risk of addiction transfer can only be properly assessed if the potential risk from the past is known. All this shows us the gray areas of legitimate exploration we are entering here.
- [10]If you have limited the test to cannabinoids, you still have a fortunate option. Since the hair samples taken must be stored for at least eighteen months for further analysis and the urine samples must also be kept in sufficient volume for this period, you can have both tested for the additional substances at a later date and thus submit comprehensive proof of abstinence from all drugs. MPU institutes have assured me that in such cases they will wait to issue their report until the results are available.
However, the whole process is extremely costly and involves delays, which you can avoid by having all samples tested right away. This also gives the expert the certainty that you have tested negative for these drugs and does not have to consider the possibility of a subsequent positive result, which makes the assessment itself easier, also from a psychological point of view. - [11]https://www.canada.ca/en/health-canada/services/drugs-medication/cannabis/resources/lower-risk-cannabis-use-guidelines.html.
- [12]This and the previous quote are taken from: German Society for Traffic Medicine & German Society for Traffic Psychology. Recommendation for a waiting period after consuming cannabis before participating in traffic (May 16, 2024): https://dgvm-verkehrsmedizin.de/wp-content/uploads/2024/05/DGVP-DGVM-Stellungnahme_Wartezeit-nach-THC-Aufnahme.pdf.
- [13]The minimum period of three months granted to occasional single users is likely to be a special case that plays virtually no role in actual assessment practice.
- [14]Bavarian Administrative Court, decision of February 4, 2025 – 11 CS 24.1712, Rn. 61.
- [15]VGH Munich, decision of May 2, 2023 – 11 CS 23.78 (withdrawal of driving license in the case of medically prescribed use of medical cannabis): Rn. 15.
- [16]The proper use of medication is also referred to as “compliance,” while awareness of potential risk factors and their avoidance is referred to as “adherence.”
- [17]VGH Munich, decision of May 2, 2023 – 11 CS 23.78 (revocation of driving license in the case of medically prescribed use of medical cannabis): Rna. 18ff.
- [18]See assessment criteria: Criterion M 1.1.N 11, p. 230: “If abstinence from alcohol is required, this must be verifiably documented for at least the last three months prior to the assessment.”
- [19]See assessment criteria, p. 329: “A blood or urine analysis cannot help to verify whether cannabis medication is being taken as prescribed.” Although hair analysis would make it possible to determine the so-called THC-A, its interpretation is highly complex and, as the head of the FTC in Munich, Prof. Dr. Frank Mußhoff, informed me verbally, is not suitable as a means of differentiation in practice.