THC limit 2024: What drivers absolutely need to know now

With the legalization of cannabis in Germany, the legal situation regarding road traffic has also fundamentally changed. Since August 22, 2024, a new THC limit has been in effect, which is binding for all drivers. Anyone who wants to drive after consuming cannabis must now know exactly what levels are permitted – and what consequences they face if they exceed them.

This guide explains everything you need to know about driving under the influence of cannabis: from the applicable regulations and fines to the special rules for novice drivers and patients with medical cannabis.

Brief overview: New THC limit for road traffic

Since August 22, 2024, a clear rule has been in effect in Germany. THC limit for road traffic : 3.5 nanograms of THC per milliliter of blood serum (3.5 ng ml). This value was scientifically determined and roughly corresponds to the impairment risk of the 0.5 per mille blood alcohol limit.

The most important facts at a glance:

• Limit: 3.5 ng/ml THC in blood serum

• Effective since: August 22, 2024

• Fine for the first offense: 500 euros

• Driving ban: 1 month

• Points in Flensburg: 2 points

Especially strict in cases of mixed consumption:

Anyone who combines cannabis and alcohol faces significantly harsher penalties. Even a blood alcohol level as low as 0.2 per mille in combination with THC can lead to:

• €1,000 fine

• 1–3 month driving ban

• 2 points in Flensburg

The police can order a blood test if they suspect THC in the blood. Only the laboratory result from the blood serum is legally binding.

Cannabis legalization and THC limit: Legal situation since April 1, 2024

With the partial legalization of cannabis on April 1, 2024, many things have changed in Germany. The Cannabis Act (officially: Consumption Cannabis Act) regulates legal possession and home cultivation – but clear limits still apply when driving.

Since April 2024, cannabis has no longer been classified as a narcotic under the German Narcotics Act (BtMG). The Cannabis Act thus creates a new legal framework. Nevertheless, driving under the influence of THC constitutes a traffic violation under Section 24a of the German Road Traffic Act (StVG).

What the cannabis law allows:

• Public space: Possession of up to 25 grams of cannabis

• At home: Possession of up to 50 grams of cannabis

• Homegrown: Up to three cannabis plants per adult in their own home

• Cultivation associations: Cannabis social clubs are expected from 2025 onwards.

• Commercial specialty stores: Not yet open nationwide

What remains prohibited:

• Cannabis use near schools, daycare centers and youth facilities

• Disclosure to minors

• Driving under the influence of THC above the legal limit

The decriminalization of cannabis use does not change the fact that driving under the influence is still strictly punished.

THC limit in road traffic: What has changed in 2024?

Before the new regulations, there was no legally defined THC limit. Courts relied on an analytical detection limit of 1.0 ng/ml – a value that could be exceeded even with the smallest traces in the blood.

The new THC limit of 3.5 ng/ml now provides legal certainty. It was passed by the Bundestag on June 6, 2024, and confirmed by the Bundesrat on July 5, 2024. The amendment to the Road Traffic Act came into force on August 22, 2024.

Old vs. New: A Comparison

aspect	Before August 2024	Since August 22, 2024
limit	1.0 ng/ml (reference value)	3.5 ng/ml (legal limit)
Legal basis	Case law	Section 24a StVG
comparable to	No match	0.2–0.5 per mille alcohol
Sanction for first-time offenders	Variable design	500 euros, 1 month driving ban

Raising the limit is intended to prevent occasional users from being punished for even the smallest residual levels – without endangering road safety. According to experts, a THC level of 3.5 nanograms corresponds to the point at which impairment relevant to driving becomes likely.

Zero-tolerance rule for novice drivers and those under 21.

For novice drivers during their probationary driving period and all persons under 21 years of age, cannabis use while driving is strictly prohibited. The regular limit of 3.5 ng/ml does not apply in these cases.

What this means:

• Even detectable amounts of THC are considered a violation.

• No tolerance threshold like with experienced drivers.

• Comparable to the 0.0 blood alcohol limit for novice drivers.

Concrete consequences:

• €250 fine

• 1 point in Flensburg

• Classification as a Category A violation

• Extension of the probationary period by 2 years

• Obligation to attend the advanced seminar

In cases of mixed drug use or repeated offenses, higher fines and, in the worst case, license revocation are possible. For minors under 18, cannabis use is completely prohibited anyway.

THC limit in practice: measurement, residual values ​​and uncertainties

Unlike alcohol, THC is broken down much more slowly in the body. The active ingredient is lipophilic – it is stored in fatty tissue and can remain detectable for days or even weeks.

The legal limit for blood alcohol concentration (BAC) in road traffic is always measured in nanograms per milliliter of blood serum (ng/ml). During a traffic stop, a preliminary test is usually carried out using saliva or urine. However, the legally binding value comes from a blood sample taken after police suspicion.

Practical examples of different consumption patterns:

Consumer type	THC concentration after consumption	Traceability
Occasional use (1 joint)	Significantly above 3.5 ng/ml in the short term	12–24 hours
Regular consumption	Residual values ​​of several ng/ml	Days to weeks
Medical intake	Constantly elevated values ​​possible	Permanently

Important to understand:

• General waiting times such as "24 hours after last consumption" are only rough guidelines.

• Metabolism, dose, frequency of consumption and body fat percentage strongly influence the breakdown.

• In regular users, residual levels above 3.5 ng/ml can still occur days after the last use.

• A safe journey is only possible when no acute effects are noticeable.

Scientific basis of the limit value of 3.5 ng/ml

The value of 3.5 nanograms was not set arbitrarily. An interdisciplinary group of experts, commissioned by the Federal Ministry for Digital Affairs and Transport (BMDV), developed it based on empirical studies.

The scientific findings:

• Below 3.5 ng/ml, experienced drivers typically do not experience any significant impairment relevant to traffic performance.

• The effect is roughly equivalent to 0.2 to 0.5 per mille alcohol – depending on individual tolerance.

• Higher concentrations (13.8–18.4 ng/ml) show significantly more pronounced deficiencies.

It's impossible to determine an exact "sobriety level" for THC. Unlike alcohol, the substance isn't metabolized linearly, and the subjective impairment varies greatly between individuals. Experts emphasize that even levels below the legal limit can lead to driving errors in inexperienced users.

Fines, driving bans and driver's licenses: Consequences of THC offenses

Anyone exceeding the limit of 3.5 ng/ml of THC in their blood serum commits an administrative offense under Section 24a of the Road Traffic Act. The consequences are clearly defined.

Overview of new regulations and fines:

violation	fine	Driving ban	Points
First THC violation	500 euros	1 month	2
Second THC violation	1,000 euros	3 months	2
Third THC violation	1,500 euros	3 months	2
Mixed consumption (THC + from 0.2 per mille)	1,000 euros	1–3 months	2

Criminal consequences:

In addition to the administrative offense, criminal consequences may also occur if:

• An accident occurs

• Other road users are endangered

• There is obvious unfitness to drive (§ 316, § 315c StGB)

The driver's license authority can order fitness tests independently of the penalty proceedings. This means that even if the penalty proceedings are concluded, the authority can require a medical report or a medical-psychological assessment (MPU).

Medical-psychological assessment (MPU) and driver's license revocation: When does it get really serious?

Not every exceedance of the limit automatically leads to a medical-psychological assessment (MPU). However, in certain situations, it becomes critical.

When the MPU (Medical-Psychological Assessment) is imminent:

• In case of repeated THC violations

• In case of accidents under the influence of cannabis

• When there is a demonstrable lack of ability to separate consumption and driving

• At very high THC concentrations (significantly above the limit)

• When used in combination with other substances

What an MPU means:

• Costs range from several hundred to over a thousand euros

• Time-consuming preparation and proof of abstinence

• Driving licence cannot be returned without passing the MPU (Medical-Psychological Assessment).

• Possible waiting periods before reissuance

Although the federal government has lowered the threshold for an automatic medical-psychological assessment (MPU) for a first offense by raising the limit, those affected can still be required to undergo an assessment if irregularities are observed.

Mixed use: Cannabis and alcohol while driving

Mixing substances is considered particularly dangerous and is subject to significantly stricter legal penalties than using cannabis alone. The effects of both substances amplify each other.

This is how cannabis and alcohol interact:

• Cannabis: Slower reaction time, altered perception, impaired sense of time

• Alcohol: Increased risk-taking, misjudgment of speeds and distances

• Combination: Increased impairment with a significantly higher risk of accidents

Legal consequences of polydrug use:

Even with a blood alcohol level as low as 0.2 per mille in combination with THC above the legal limit, the following risks are possible:

• A fine of at least 1,000 euros.

• 2 points in Flensburg

• 1–3 month driving ban

In the event of accidents or demonstrably severely impaired driving ability, courts can also consider mixed consumption as a criminal offense under Section 315c of the German Criminal Code – with possible prison sentences.

Clear recommendation: Never drive after any combination of alcohol and cannabis. The risks are too high, the consequences too serious.

Particular risks for novice drivers when using mixed substances

Novice drivers are particularly vulnerable due to their less experience on the road. Even stricter regulations apply to them.

What novice drivers need to know:

• Zero tolerance for alcohol (0.0 per mille) AND cannabis

• Even a single instance of mixed substance use results in a Category A offense.

• Probationary period extended by 2 years

• Obligation to attend the advanced seminar

• In case of accidents: Insurance companies can reduce benefits or demand recourse.

The consequences can jeopardize your driver's license even before the probationary period is over. This applies to those under 21, regardless of how long they have held their license.

Medical cannabis and THC limits: What applies to patients?

Many people in Germany use medically prescribed cannabis – for example, for chronic pain, spasticity, or certain psychiatric diagnoses. The Medical Cannabis Act regulates its legal therapeutic use.

The good news: Section 24a of the German Road Traffic Act (StVG) provides an exception for the use of medications permitted under traffic law. This also applies to medical cannabis when taken as prescribed.

Conditions for the exception:

• Valid medical prescription

• Take according to the prescribed dosage.

• No acute intoxication or significant impairment

• Stable response to the medication

Recommendations for patients:

• Carry your medical certificate and cannabis patient ID card.

• During check-ups, calmly and objectively point out the medical indication.

• Never drive if you are experiencing acute effects.

• Regular consultation with the treating physician regarding fitness to drive

The driver's license authority can assess on a case-by-case basis whether the individual's fitness to drive remains intact. Doubts may arise despite a prescription in cases of high doses or additional alcohol consumption.

Distinction: Therapeutic use vs. abusive consumption

Courts and authorities clearly distinguish between documented long-term medication and spontaneous recreational use.

What is considered therapeutic use:

• Regular, medically supervised intake

• Documentation through prescriptions and medical reports

• Stable dosage without intoxication

• Compliance with traffic medicine regulations

What is considered abusive consumption:

• Irregular or clandestine use outside the prescribed regime

• Higher doses than prescribed

• Combination with alcohol or other substances

• Lack of medical supervision

In cases of doubt, medical or medical-psychological assessments may be requested. Patients should carefully document their medication intake and attend regular check-up appointments.

Criticism, open questions and outlook on the THC limit

The new limit of 3.5 ng/ml is viewed differently by experts, the police, and interest groups. The current state of the discussion indicates that it represents a political and scientific compromise.

Criticisms from various directions:

• Some experts are calling for higher thresholds (4–7 ng/ml) and a tiered system similar to alcohol.

• The ADAC continues to recommend complete abstinence before driving.

• Criticism that no binding rule regarding saliva or rapid tests was included.

• Concerns regarding fairness for long-term consumers with high residual values ​​but no acute impairment

How courts decide:

Despite the clear limit, courts must still rule on a case-by-case basis – especially in the following cases:

• Extremely high THC levels

• Visible driving instability

• Mixed use with other substances

• Accidents involving personal injury

Outlook on possible developments:

• Standardized saliva tests for faster checks

• Digital evaluation methods for assessing acute impairment

• Regular review of the limit value based on new study results

• Possible adjustment of the MPU limit values ​​(currently discussed: 13.8–18.4 ng/ml)

Public opinion and road safety

Surveys – for example by automobile clubs in January 2024 – show a clear skepticism towards cannabis while driving among the population.

The survey results show:

• A majority consider driving after cannabis use to be dangerous and difficult to assess.

• At the same time, a significant proportion of the population has already consumed cannabis.

• The practical implications of the new limit value affect millions of people.

Conclusion on road safety:

• The limit value offers more legal certainty than the old regulation.

• Public awareness campaigns remain necessary to communicate risks.

• Individual responsibility of each person is crucial.

• The health of all road users takes precedence over convenience.

The Green Party and the coalition parties have created a framework with the new law that enables consumption and regulates mobility. Practical implementation will show whether the limit of 3.5 ng/ml represents the right balance between freedom and security.

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What you should bring:

The THC limit of 3.5 ng/ml in blood serum has been legally binding for driving under the influence in Germany since August 2024. Anyone who drives after consuming cannabis bears full responsibility for their own fitness to drive. There are no fixed waiting periods – the effects of THC vary too greatly from person to person.

Before every trip, check whether you are truly fit to drive. If in doubt, don't drive. The consequences of a violation – from fines and license revocation to a mandatory medical-psychological assessment (MPU) – can affect your mobility and daily life for years.