License suspension for cannabis

Procedure after a positive blood sample

After a positive test the police seize the licence on the spot as a precaution. Within weeks the cantonal traffic office issues a written suspension order – either a warning suspension or a safety suspension.

For one-off use a warning suspension (min. 3 months) is usually ordered. Where regular use is suspected – e.g. high THC-COOH values – the authority orders a medical fitness review, which may lead to a safety suspension.

Warning vs. safety suspension

• Warning suspension: fixed duration, educational purpose (typ. 3–12 months for first cannabis offence).
• Safety suspension: indefinite – licence returned only after a new positive medical fitness review.
• Both are entered into the ADMAS register and show up in future checks.

Swiss practice: procedure, deadlines and costs

Licence withdrawal is an administrative measure of the cantonal road traffic office and runs separately from criminal proceedings — both can run in parallel and both sanctions hit the same person. After a positive blood sample the licence is usually withdrawn immediately as a precaution (Art. 30 VZV), before the penal order even exists. The minimum duration is three months for a first serious offence (Art. 16c SVG) and one month for a medium-serious offence (Art. 16b SVG); repeat offences within ten years lead to far longer withdrawals, up to indefinite. The right to be heard is granted in writing with a short deadline (often ten to twenty days) — professional drivers and anyone occupationally dependent on a vehicle should definitely use it, because occupational need can be weighed, though never below the statutory minimum.

Procedure and criteria of the traffic medical assessment

If the cantonal road traffic office has doubts about fitness to drive due to an incident or consumption habits, it orders a traffic medical assessment. This examination is carried out by recognized traffic medicine specialists and serves to assess whether there is an addiction or abuse that endangers driving safety. As part of this assessment, those affected must provide detailed information about their consumption habits, undergo a physical examination and submit biological samples. The assessors evaluate both the physical and mental condition of the driver with regard to the requirements of road traffic.

The criteria for a positive assessment are strict and require a comprehensible reflection on one's own consumption. In the event of suspected regular consumption, the authorities generally require proof of stable abstinence over a specified period, which must be verified by regular hair analyses or unannounced urine tests. Only when the assessors confirm a permanent change in behavior and stable abstinence can the Road Traffic Office lift the safety-related revocation. A negative assessment means that the driving licence remains revoked until further notice.

Federalism in road traffic law: Cantonal differences in enforcement

Although the Road Traffic Act is a federal law, the enforcement of administrative measures falls under the jurisdiction of the individual cantons. In practice, this leads to noticeable differences in how driving licence revocations following cannabis consumption are handled. The cantonal Road Traffic Offices exercise their discretionary power differently. While some cantons quickly order a traffic medicine assessment even at low measured THC levels in the blood, other authorities are more reserved and examine the specific circumstances of the individual case more closely before taking costly measures.

In addition, processing times vary considerably between cantonal authorities. In densely populated cantons with a high volume of cases, the procedure from the blood draw to the final ruling can take several months, which involuntarily extends the period of provisional revocation. The coordination between the prosecuting authorities, which determine the fine or penalty, and the administrative authorities, which decide on the licence revocation, also varies in speed from canton to canton. This makes it difficult for those affected to accurately predict the exact process and overall duration of the proceedings.

Scientific Basis: The THC Limit in Blood

In Switzerland, a strict limit for tetrahydrocannabinol in the blood applies to active participation in road traffic. This is set at 1.5 micrograms of THC per litre of blood serum and represents the analytical detection limit, which in practice equates to a zero-tolerance rule. Since THC is metabolised individually and irregularly in the human body, the waiting time between consumption and fitness to drive is difficult to estimate. Even if consumption occurred many hours or even a day ago, the limit in the blood can still be exceeded.

In addition to active THC, laboratories also determine the inactive metabolite THC-carboxylic acid, known as THC-COOH. While active THC indicates current impairment, the concentration of the metabolite provides information on the frequency of past consumption. High levels of THC-COOH indicate regular or chronic consumption and often serve as the authorities' primary argument to fundamentally question driving aptitude and order a traffic medical assessment. The detection of this metabolite is therefore of central importance for the subsequent administrative procedure.

Special considerations for patients with medical cannabis

Since the amendment of the law in August 2022, medical cannabis can be prescribed by doctors in Switzerland without an exceptional permit from the FOPH. However, this facilitation in narcotics law does not mean that patients are permitted to participate in road traffic without restriction. Even under a medically prescribed therapy, driving aptitude must be guaranteed at all times. The treating physician is obliged to inform patients about the effects on their fitness to drive and to check whether taking the medication impairs road safety.

During a traffic check, presenting a prescription or a patient card does not automatically protect against the legal consequences of a positive THC result. If active THC is detected in the blood, a case-by-case review is carried out by the cantonal road traffic office. This examines whether there is a stable adjustment to the medication and whether driving safety is guaranteed despite the medication. If there are doubts about driving aptitude, the authority can also request a traffic medical assessment for medical users in order to obtain an expert confirmation of their fitness to drive under medication.

How long does the traffic medical assessment take on average?

The traffic medical assessment usually takes several months, as a monitoring period of at least three to six months is generally required to prove stable abstinence. During this phase, those affected must submit regular, unannounced urine tests or undergo hair analysis. The expert report is only prepared once all laboratory findings are available and the final interview with the traffic medicine specialist has taken place. The exact total duration depends heavily on the cantonal authorities and individual requirements.

Does the limit of 1.5 µg/L THC in blood also apply to CBD products?

Yes, the legal limit of 1.5 micrograms of THC per litre of blood applies without exception to all drivers, regardless of whether the THC was ingested through the consumption of CBD products. Since CBD hemp in Switzerland is also allowed to contain up to one percent THC, regular or intensive consumption of CBD products can lead to the limit in the blood being exceeded. Anyone participating in road traffic should be aware of the risk of THC accumulation due to CBD.

Who bears the costs of the traffic medical examination?

The entire costs for the traffic medical assessment and the associated laboratory analyses must be borne by the person concerned. These costs quickly amount to several thousand francs, as both the fees of the experts and the chemical-toxicological analyses of urine or hair samples must be paid privately. The cantonal road traffic offices also charge their own fees for processing and issuing the corresponding rulings.

Can a positive rapid test on site be refused?

Yes, a rapid saliva or urine test by the police on site can in principle be refused, but in practice this almost always leads to a mandatory blood draw. In the event of reasonable suspicion of unfitness to drive, the police are authorised to order a blood sample at the hospital, which is legally binding and cannot be refused. Refusing the rapid test therefore usually only delays the procedure and does not prevent subsequent official measures.

Frequently asked questions

Can I appeal?

Yes, within 30 days of the notice at the cantonal administrative court. Legal advice is strongly recommended.

What if I drive anyway?

Driving without a licence is a criminal offence (Art. 95) – up to 3 years imprisonment or a fine, plus a new, longer suspension.

Can I do anything about the precautionary licence withdrawal?

You can respond during the right-to-be-heard stage and appeal, but the statutory minimum is never undercut. Occupational need can only affect the portion beyond that minimum.