Who may order a cannabis test if there is suspicion?

If there is suspicion of cannabis use while driving, the police can carry out a check on the spot with preliminary test devices. The Police Advice Service (Polizei-Beratung) describes that drug use can be detected at a traffic check with such devices through sweat, saliva or urine. Taking part in such a preliminary test is voluntary. A blood sample is generally ordered by a judge under § 81a para. 2 StPO. If delay would endanger the success of the investigation, the public prosecutor's office and its investigating officers may also order it. If there is suspicion of an administrative offence under § 24a StVG, a blood sample requires no judicial order under § 46 para. 4 OWiG. This guide explains the procedure, the legal consequences and the places you can turn to.

What a preliminary test at the police shows

A preliminary test first provides an indication that a particular substance can be detected. What happens next depends on the result, on the situation at the check and on further examination steps. The test devices are therefore the start of a process and not its end. For the legal assessment, what is established in the further proceedings is what counts.

The statutory limit for cannabis in road traffic refers to blood serum. Blood serum is the liquid part of the blood that remains once the blood cells and clotting factors have been removed. Anyone who wants to know whether a value in the law has been reached must therefore look at this measured quantity. A preliminary test on the spot does not replace this measurement.

Who may order the test?

For the blood sample, § 81a StPO applies: the order lies with the judge, and where delay would endanger the success of the investigation, also with the public prosecutor's office and its investigating officers (§ 81a para. 2 sentence 1 StPO). If there is suspicion of an administrative offence under § 24a StVG, the blood sample requires no judicial order under § 46 para. 4 OWiG. If there is suspicion of a criminal offence under § 315a, § 315c or § 316 of the Criminal Code (StGB), the blood sample also requires no judicial order (§ 81a para. 2 sentence 2 StPO). For the preliminary test on the spot, the Police Advice Service names the traffic check as the framework. Ask the officers on what basis the test is carried out and which steps follow. Courts decide case by case, and a specialist lawyer for traffic law can classify the situation.

What a positive result can legally mean

For cannabis in road traffic, the THC limit is 3.5 ng/ml in blood serum (§ 24a para. 1a StVG). If the value is 3.5 ng/ml or higher, this is a breach under § 24a StVG. The Police Advice Service also describes that, without signs of impairment and without driving errors, it is an administrative offence punished with a fine and a driving ban. The amount of the fine is explained in the article on the fine levels under § 24a StVG.

More on the limit is in the article on the THC limit of 3.5 ng/ml.

Driving ban, notification and criminal offence

When a fine is imposed under § 24a para. 1 to 2a StVG, a driving ban is generally ordered as well (§ 25 para. 1 StVG). The driving licence authority is the body to which you can address questions about the consequences for your driving licence. More on this is in the article on the driving licence authority.

The situation is different if consumption leads to driving errors. The Police Advice Service names drug-related driving errors, endangering others or an accident as circumstances in which the act can be a criminal offence. Under § 316 StGB it requires that the driver is unable to drive safely because of intoxicants, and under § 315c StGB a concrete endangerment of people or valuable property; an accident alone does not make it a crime. The matter is then no longer just a fine matter. The threshold for a criminal offence therefore cannot be determined from the test result alone. It also depends on how the vehicle was driven.

Alcohol and cannabis combined

The combination is particularly risky. Under § 24a para. 2a StVG, combining THC and alcohol is a separate offence. The law also covers alcohol consumption and starting a journey under the influence of alcohol. Anyone who smoked cannabis in the evening and still drinks wine should leave the car where it is, before the question of a test even arises. More on this combination is in the article on criminal liability when driving after cannabis.

The exception for prescribed medicines

Under § 24a para. 4 StVG, paragraphs 1a, 2 sentence 1 and 2a do not apply if the substance comes from the intended intake of a medicine prescribed for a specific illness. The exception is therefore tied to a prescribed medicine for a specific illness. How this works in everyday life for medical cannabis is explained in the article on medical cannabis at the wheel.

What you can do concretely

• Stay calm and do not let the check escalate.
• Ask on what basis the test is carried out and what happens next.
• Note when and where the check took place and which people were involved.
• Before decisions on statements or legal remedies, ask a specialist lawyer for traffic law.
• For questions about the driving licence, contact the competent driving licence authority.

Prevention: plan the journey in advance

The safest way is to settle the journey home before consumption. Anyone who has smoked or eaten cannabis should arrange an alternative for the journey before the evening begins. Especially with alcohol involved, the situation changes quickly, and then only prior planning helps. The guide Am I allowed to drive after cannabis? answers the question of whether you can still drive in more detail.

Why young people should be especially careful

The young brain is in an important stage of development, and cannabis can affect that development. The BIÖG page for young people warns that in the worst case a school or vocational qualification is at risk, because memory works significantly less well. According to drugcom.de, starting early has lasting effects on cognitive performance. Young people in particular should therefore weigh up carefully before driving or consuming.

Where to get help

For questions about proceedings, the driving licence and rights, a specialist lawyer for traffic law helps. For questions about your own consumption, local addiction counselling services are the right address, and advice is also available online through suchtberatung.digital. The Sucht & Drogen Hotline (addiction and drugs hotline) can be reached on 01806 313031, and information is available on the hotline's website. The notes on rights during drug checks explain what to expect during a police check.