Since cannabis was legalised in 2024, a THC limit of 3.5 ng/ml in blood serum applies in road traffic instead of the previous 1.0 ng/ml, and the order for an MPU (medical-psychological assessment, Medizinisch-Psychologische Untersuchung) has its own legal basis in § 13a FeV (Driving Licence Regulation, Fahrerlaubnis-Verordnung). Occasional use no longer automatically calls your fitness to drive into question. Things remain as strict as before for mixed use, dependence and driving with significantly raised levels. The page MPU for cannabis explains exactly when an MPU is likely and how it works.
What exactly has changed as a result of legalisation?
Legalisation has mainly changed three things: the limit, the legal basis for the MPU and the view taken of occasional use. The following table compares the most important points.
| Topic | Before 2024 | Since 2024 |
|---|---|---|
| THC limit in road traffic | 1.0 ng/ml | 3.5 ng/ml blood serum (administrative offence under § 24a (1a) StVG) |
| Legal basis of the MPU order | general drug provisions | separate provision § 13a FeV (modelled on the alcohol rule § 13 FeV) |
| Occasional use | could raise doubts about fitness to drive | no longer automatically calls fitness to drive into question |
| Repeat drives | – | § 13a FeV refers to „repeated“ offences, without a fixed number |
| Authority practice | – | MPU as a rule from the 2nd cannabis drive |
| Exception: additional facts | – | MPU possible from the 1st drive |
| Assessors' standard | older assessment criteria | 5th edition of the assessment criteria (2026), adapted to the Cannabis Act |
The table is a guide, not legal advice. What is binding is always the current wording of the law and the specific order from your driving licence authority (Fahrerlaubnisbehörde).
What does the limit of 3.5 ng/ml mean?
The limit of 3.5 ng/ml THC in blood serum marks the point from which driving under the influence of cannabis is an administrative offence under § 24a StVG (Road Traffic Act). Below this level, this offence does not apply. However, that is not a free pass: if you show signs of impairment or cause an accident, you must still expect consequences and doubts about your fitness to drive.
The unit is important: measurement is in blood serum, not in urine or with a rapid test. How long you stay above the limit after using cannot be predicted in general terms. If you want to be on the safe side, keep use and driving strictly separate.
When does the authority order an MPU today?
For cannabis, the driving licence authority today usually only orders an MPU from the second drive above the limit. The basis is § 13a FeV, which provides for a medical-psychological expert report (Gutachten) in cases including „repeated road traffic offences under the influence of cannabis“.
„Repeated“ without a fixed number
The law does not state a specific number of drives. The often-quoted rule „only from the 2nd drive“ is common authority practice, not the wording of the law. The assessment can therefore differ in individual cases – your authority's order is what counts.
Additional facts: MPU after the first drive
The authority can order an MPU after the very first drive if there are additional facts (Zusatztatsachen). Typical examples are:
- an acute THC level of more than 11 ng/ml,
- a metabolite level of THC-COOH above 150 ng/ml,
- mixed use (for example cannabis together with alcohol),
- signs of dependence.
In addition, § 13a FeV provides for an MPU if there are signs of cannabis misuse, if the driving licence was previously withdrawn for these reasons, or if it has to be clarified whether misuse or dependence no longer exists. You can find more background on the page MPU for cannabis.
What has stayed the same despite legalisation?
What has stayed the same is that mixed use and dependence continue to be taken very seriously. Legalisation has relaxed the approach to occasional use, not to problematic use.
Mixed use
Mixed use, i.e. cannabis together with alcohol or other substances, counts as an additional fact. It can lead to an MPU order even after a single drive. Assessors regard it as an indication that control over use is no longer assured.
Dependence
If you are dependent on cannabis, fitness to drive is ruled out until 1 year of proven abstinence is available. If facts justify the assumption of dependence, § 13a FeV first provides for a medical report by a doctor. Proof is then provided through a recognised abstinence programme, as described on the page Proof of abstinence.
Other drugs
Nothing has been relaxed for other narcotics such as cocaine, amphetamine or opiates. § 14 FeV still applies here, and even a single use can rule out fitness to drive – even without driving.
Does the new rule also apply to medical cannabis?
A separate rule applies to medical cannabis: the medication privilege (Medikamentenprivileg) under § 24a (4) StVG. If cannabis is prescribed to you by a doctor and you take it as directed, you do not fall under the 3.5 ng/ml administrative offence. However, the privilege does not protect you if you show signs of impairment. The guide Medical cannabis and driving explains the details.
What does this mean for an ongoing or old MPU case?
Whether the new legal situation changes anything in your specific case depends on the timing, the file and the order. A general statement is not possible here. The basic rule is: the authority must state a specific question in the order, and it is exactly this question that the expert report answers.
If you have doubts about whether an order is lawful, or if a deadline is running, have this checked by a specialist lawyer for traffic law (Fachanwalt für Verkehrsrecht). Not every order is lawful, but this can only be judged in the individual case.
How do assessors evaluate cannabis today?
Since 2026, assessors have worked according to the 5th edition of the assessment criteria (Beurteilungskriterien), which has been adapted to the Cannabis Act. Cannabis has its own classification system in it, based on § 13a FeV.
The psychological interview remains decisive. The assessor checks whether you have understood why the drive happened, what has changed since then and why the change is stable. Stories of a one-off slip do not help if the file shows a pattern.
For a positive expert report you usually need three things, credible and free of contradictions: insight into the problem of your own pattern of use, a concrete change in behaviour and stability, with an inner motive that goes beyond just „getting the licence back“. Legalisation has not changed this.
What you can do now
- Read the order carefully: which legal basis (§ 13a FeV) and which question does the authority state?
- Request file inspection (Akteneinsicht) so that you know all the levels (THC, THC-COOH) and incidents.
- Check whether abstinence is required – if there are signs of dependence, you should start a recognised programme immediately, because the 12 months are the bottleneck.
- Have unclear legal questions checked by a specialist lawyer for traffic law.
- If an MPU is coming up: find suitable preparation.
Frequently asked questions
Will I get an MPU after a single cannabis drive above 3.5 ng/ml?
Usually not, because authorities mostly only order the MPU from the 2nd drive. However, if there are additional facts, for example more than 11 ng/ml THC, THC-COOH above 150 ng/ml, mixed use or signs of dependence, it is possible after the first drive.
Where is the two-drives rule in the law?
Nowhere, word for word. § 13a FeV only refers to „repeated“ offences under the influence of cannabis, without a fixed number. The threshold of the 2nd drive is common authority practice.
Is occasional cannabis smoking unproblematic for the driving licence today?
Occasional use no longer automatically calls fitness to drive into question. What remains decisive is that you keep use and driving separate and do not drive with 3.5 ng/ml or more THC in your blood serum.
Do I need proof of abstinence if I am dependent on cannabis?
Yes. In the case of dependence, fitness to drive is ruled out until 1 year of proven abstinence is available. Proof (Abstinenznachweis) is provided through an accredited programme with urine or hair tests.
