Am I allowed to carry cannabis in a car?

For adults, carrying cannabis in a car is not automatically prohibited, as long as the quantity possessed is kept within the limit. Driving under the influence remains prohibited. This separation is the core of the rule, and it is often confused in daily life: possession is a question of the KCanG, driving a question of the Road Traffic Act (Straßenverkehrsgesetz, StVG).

Possession yes, driving under the influence no

Under § 3(1) KCanG, adults may possess up to 25 grams of cannabis for personal use. This quantity applies to people aged 18 and over. When out and about, the 25-gram limit under § 3(1) KCanG applies to personal use. The quantity is what matters.

Those who drive, by contrast, are subject to the rules of road traffic. The law prohibits driving under the influence of intoxicating substances. Testing for this takes place in the blood, using limits set out in § 24a StVG. Possession in the vehicle changes nothing about this test, because a check measures the active substance in the body.

The limits at a glance

The following table shows the rules that § 24a StVG sets for drivers. It is an overview and does not replace the text of the law.

Rule	Value	Provision
Alcohol in the blood	0.5 per mille	§ 24a(1) StVG
THC in blood serum	3.5 ng/ml	§ 24a(1a) StVG
Intoxicating substances from the list	proof in blood serum	§ 24a(2) StVG
THC and alcohol together	separate offence	§ 24a(2a) StVG

The THC value of 3.5 ng/ml refers to blood serum.

Why the KCanG has no simple limit

Many people expect the KCanG to set a clear value for driving. The law does not do so. Instead, § 44 KCanG tasks a working group with developing a proposal for the value of a THC concentration in the blood. The value that applies on the road is the one in § 24a StVG.

This means that the limit in road traffic is currently regulated under § 24a StVG, not under the KCanG. Anyone relying on a value from forums or personal accounts takes a risk that cannot be calculated.

THC and alcohol together

The combination is especially risky. Under § 24a(2a) StVG, the combination of THC and alcohol is a separate offence. It builds on the act under § 24a(1a) StVG, that is, driving a motor vehicle with 3.5 ng/ml or more of THC in blood serum, and applies in addition where alcohol has been drunk or the journey begins under the influence of alcohol. For this offence, the law provides a higher fine range than for the other violations (§ 24a(3) StVG).

The combination is also problematic for health. Anyone using cannabis and alcohol together often experiences the effect differently from what they expect. The article on mixed use with alcohol explains the risks in more detail.

Medicines and medical prescriptions

Section 24a(4) StVG provides an exception for medicines. Under it, subsections (1a), (2) first sentence and (2a) do not apply if the substance comes from taking a medicine prescribed for a specific illness as intended. This exception concerns cannabis prescribed by a doctor, not recreational use. Anyone taking medication should therefore read the package leaflet and clarify with their doctor whether and how driving is possible.

What happens at a check

A fine under § 24a StVG can follow if a limit is exceeded or an intoxicating substance is detected. The amount of the fine depends on the circumstances of the individual case and is stated in the notice. For a fine under § 24a(1) to (2a) StVG, § 25(1) StVG generally also requires a driving ban to be ordered. The article on the level of fines for cannabis violations gives an overview of the system.

The driving licence authority can advise on possible consequences for the driving licence that go beyond the fine. If you have received a notice, have it checked by a lawyer specialising in traffic law.

Practical rules for everyday life

Anyone who possesses cannabis and uses a car can reduce the risks with a few rules. Leave the car where it is if you have consumed, and plan the journey home by train, taxi or with a sober person. Do not keep cannabis in the vehicle unless you need it, and keep the quantity within the possession limit. Plan the journey so that there is ample time between consumption and driving.

These rules are no licence to do anything. They help you limit the risks, but they do not replace the decision to stay sober at the wheel.

Passengers and possession in the vehicle

Anyone carrying cannabis in a car is not alone in this. Passengers can be affected if they also possess or consume cannabis. How the attribution is assessed in an individual case is decided by authorities and courts. It makes sense to agree before the journey who owns which material, and to keep quantities separate.

A mix-up is common when cannabis from the flat is left in the car, or stays in the car after an appointment with several people. Anyone travelling with others should keep the attribution in view.

What effect and fitness to drive mean

A limit is a legal threshold and does not tell you whether you can drive safely. Whether you are fit to drive cannot be reliably judged from outside. After consuming, do not drive, even if you think you are within the legal limits.

What you can do now

Read § 24a StVG in the text of the law before you make a decision. The wording on possession is at § 3 KCanG, and the rule on the THC limit at § 24a StVG. For questions about a specific case, a lawyer experienced in traffic law can help. An overview of road traffic is available on the road traffic topic page. This article does not replace legal advice.