Cannabis & driving license: THC limit & driving ban

New cannabis traffic law from June 2024

With the legalization of cannabis in Germany, road traffic law has also been adapted. Since August 22, 2024, an official THC limit value has applied in road traffic. This replaces the previous zero-tolerance practice (1 ng/ml as an administrative offense threshold). The new regulation is more precise, but still strict – and has considerable consequences for cannabis users.

The new THC limit: 3.5 ng/ml

Since August 22, 2024: THC limit value in blood serum: 3.5 ng/ml for misdemeanors.

Background: The limit value commission (Federal Highway Research Institute) recommended 3.5 ng/ml as a scientifically valid value above which an impairment of driving safety is likely. This value corresponds approximately to the per mille equivalent of 0.2 per mille alcohol.

How long is THC detectable?

This is the core problem for cannabis users. THC itself (the intoxicating active ingredient) is rapidly metabolized. In the blood serum:
– Acute intoxication: THC >3.5 ng/ml for 2-6 hours after consumption
– After single use: Below 3.5 ng/ml usually after 6-12 hours
– With regular use (daily): THC balance in body fat → serum level can still be above 3.5 ng/ml days after use
– Chronic users: THC detectable in urine (not blood!) up to 30 days after last use

The limit refers to blood serum THC, not THC-COOH (inactive metabolite in urine). If you only have THC-COOH in your blood (not active THC), you are not necessarily over the limit.

MPU (medical-psychological examination)

The MPU (colloquially: idiot test) can be ordered for
– THC value above 3.5 ng/ml during a traffic check
– Combination of cannabis + alcohol
– Caught with regular consumption with suspicion of lack of separation ability

Separability is the key word: Anyone who demonstrably consumes cannabis regularly (even legally in a social club) and drives at the same time loses the MPU – even if the specific THC value was below 3.5 ng/ml.

MPU failure Consequence: Withdrawal of driving license. Re-issue only after proof of abstinence and a new MPU.

Medical consumers and driving licenses

Patients with a cannabis prescription (medical cannabis) are subject to the same THC limits. A medical prescription does not protect against driving bans if THC above 3.5 ng/ml is detectable in the blood. Recommendation for medical users:
– Do not drive in the hours after ingestion
– Daily dose in the evening – not in the morning before driving
– Dronabinol capsules (predictable PK progression) vs. inhaled (fast peak, fast decomposition)

FAQ: Cannabis and driving license

Summary

THC limit of 3.5 ng/ml in blood serum has applied since August 2024. Below that: legal to drive. Above: 500-1,500 EUR, driving ban, points. Cannabis + alcohol: criminal. Chronic users have elevated serum levels for days – caution. Ability to separate is decisive for MPU. Medical users enjoy no special status – same limits. Cannabis Social Club for further legal questions on legalization; Cannabis international for legal situation in other countries.