THC in road traffic - with zero tolerance

Since 2005, the so-called zero tolerance to THC in road traffic is now in force. What exactly is prohibited? When is the driver's license in danger? We give an overview of the handling at the road traffic offices and the forensic medicine.

Previously, the driving ability of a person was determined by three pillars: first, by the police report, second, by the general medical examination, third, by the blood test. As of January 1, 2005, the old system was changed under the title of “zero tolerance”. Now, the assessment of driving ability is no longer based on the three pillars, but as soon as THC is detectable in the blood, it is assumed that driving incapacity exists.

These two terms mean two very different things. Fitness to drive refers to the general ability to drive a car, i.e. whether someone should be issued a driver's license at all. Driving ability, on the other hand, refers to the specific ability to drive a car at a given time. Someone who has been denied the ability to drive (for example, because of dependence on narcotics) can therefore never be capable of driving. However, if someone is incapable of driving at a particular moment (for example, due to being under the influence of narcotics), that person may well have a general fitness to drive.

The public prosecutor is responsible for the punishment of an inability to drive, but the STVA or its Office for Administrative Measures (AMA) is responsible for the clarification of the fitness to drive.

THC use can be detected in the human body in several ways. On the one hand, there are (cheaper) tests for urine that can only detect a breakdown product of THC. On the other hand, the (more expensive) blood test can measure both the psychoactive THC and the degradation product in a legally binding way.

THC, more precisely ∆9-tetrahydrocannabinol, is the main active ingredient in hash and weed. It mainly causes the “drive-in”. Actually, zero tolerance has been in effect for this substance for two years. But in practice, it turned out that it is not at all easy to reliably detect traces of THC in the blood. Therefore, after some back and forth, a limit value of 1.5 µg/liter of blood was set, albeit extremely low. “µ” means microgram, or one millionth of a gram. Sometimes the measured value is also given in ng/milliliter, which then means one billionth of a gram per thousandth of a liter (the actual number before micro- or nanogram is the same). However, since measuring devices always have a certain inaccuracy, a confidence range of +/-30% is calculated from the measured value. The lower value is important here - if this is below the 1.5 µg/liter, the person being tested is still in the green zone. This leads to an effective limit value of 2.14 µg/liter.

This value is very low, it can still be exceeded hours after the last consumption, with regular consumers even after days. It has nothing to do with the actual effect. Nevertheless, anyone with a THC level above the limit is considered unfit to drive. Anyone who drives a car with such a value is legally committing a misdemeanor and can be punished with up to three years in prison. In addition, the driving license will be confiscated for at least three months.

In addition to THC, THC-COOH (or more precisely, tetrahydrocannabinol carboxylic acid) is also measured. This is also measured in the simpler urine tests and is a non-psychoactive breakdown product of THC. Although the value determined in the blood is not relevant to driving ability by law, a practice seems to have formed among the examining institutes of forensic medicine IRM that if the THC-COOH value is 40 µg/liter or more, there is an urgent suspicion that driving ability in general must be questioned. On the recommendation of the IRM, the STVA can then have the fitness to drive clarified.

A medical assessment of fitness to drive by a public health officer can be initiated in several ways (see graphic on next page). The medical officer (often an employee of an IRM) conducts the examination. The costs must be paid in full by the person examined, and an advance payment must even be made. The driver's license can either be withdrawn before the examination (if there are indications of addiction), or it can be retained until the examination is completed.

Occasional THC use is considered by IRM to be compatible with the PW driver's license (but the higher license categories for cabs or trucks are generally revoked). Ultimately, however, the STVA must decide on the withdrawal. There are differences between the various cantonal STVA. In the case of a clean reputation and no other conspicuous circumstances (psychological, other drug use, previous files, indications from the police report), the PW driver's license is retained for occasional use. “Occasional” here means a range from “one joint a week” to “three or four joints at the weekend”. Daily use, on the other hand, is considered a problem by all STVAs interviewed - in this case, the STVAs would have the fitness to drive clarified by a doctor.

Anyone who consumes THC and drives a car is therefore almost always committing a misdemeanor, even if driving and consumption are separated. Unless you only consume a little on Friday evening, don't drive a car on the weekend and don't consume anything, and don't drive a car again until Monday.

An overview of the procedure can be found in this PDF: Procedure driver's license

Someone smokes a joint outside without driving, the police checks him, finds hash or weed and he admits to regular consumption during questioning. The police then report this person for narcotics consumption and, if he or she has a driver's license, report the person to the Road Traffic Authority (STVA) because there is a suspicion that the person being checked could pose a danger in road traffic.

Someone is checked while driving, the urine sample is positive and THC is detected in the blood by a doctor, but below the limit value. Then a report is issued for drug use (as in the first example), but not yet a report for driving under the influence of drugs. The police report then also goes to the STVA because it seems possible that a drug addiction exists.

Someone is checked while driving, the urine sample is positive and THC above the limit is detected in the blood by a doctor. Then a report because of narcotics consumption (as in the first example), in addition also a report because of driving under the influence of narcotics. The police report is then also sent to the STVA, because there is an urgent suspicion of drug addiction.

The district attorney (or prosecutor) combines all illegal acts into one sentence.

For the admitted consumption and the amount of hash or weed found, there is usually a fine, as this is only a contravention.

Driving with THC in the blood below the limit is not relevant in terms of criminal law. There is therefore no punishment for this. However, proven or admitted use/possession is punishable by a fine.

If driving with THC above the limit is added to this, the penalty becomes massively higher as this is a misdemeanor. Here, penalties ranging from 500 francs fine to a few thawing francs fine to a few days in jail are pronounced.

Attention: If further illegal actions are added (such as defects on the car, further traffic rule violations or even an accident caused, but also other violations such as illegal possession of weapons, insulting officials, passing on THC products, etc.), these offenses are also combined in one sentence. Therefore, most verdicts are not directly comparable and the range is accordingly large.

The Road Traffic Office is responsible for any driver's license withdrawal and clarification of fitness to drive.

In this case, there is not always any reason to fear that the driver will be disqualified from driving - after all, no traffic regulations have been broken. However, if regular, high consumption is admitted in the police report, the STVA can initiate a clarification of fitness to drive. However, this seems to happen rather rarely, especially when “psychological conspicuousness” is reported. The police and the STVA have a great deal of discretion here.

Here, too, there are no violations of traffic regulations, so the STVA would actually have no reason to do anything. However, in addition to THC (which is below the limit in this case), THC-COOH is also measured. Some STVA then want to clarify the fitness to drive if the value of THC-COOH is above 40 µg/liter of blood. In forensic medicine, it is often assumed that such a value is associated with regular, higher consumption. Therefore, one must then assume a dependence. This, however, is always the basis for withdrawing the driving license or at least having the fitness to drive medically clarified.

Here THC is detectable above the limit. Therefore, the license will be withdrawn by the STVA for at least three months, possibly longer (this depends on the previous files and criminal record). Further, the traffic office would not have to do anything (if the reputation is clean and no other violations have occurred). However, in this case, most STVAs will order a medical examination to determine fitness to drive. This is very likely to happen if the THC-COOH level is high.

What comes out of the official medical examination depends very much on the corresponding doctor and the behavior of the subject during the examinations. But once these mills are running, it is very difficult to avert measures of the STVA. If the driver's license is retained, conditions are often imposed such as controlled THC abstinence (urine checks every two weeks for a year at the expense of the subject).

Appeals are possible against all decisions of the STVA. However, you usually have to pay an advance on costs, which you only get back if you win the administrative court case. But this is unlikely. And even if you win (there are individual examples of this), the lawyer's fees are around 5,000 and the IRM investigation costs around 3,000 francs. In the end you might get 2'000 francs compensation…

Anyone who has caused an accident can be held personally liable for the costs of the accident if THC has been detected in the blood

Recourse: In the event of an accident resulting in damage, the insurance company must pay for the damage (e.g. medical costs of the injured person and/or costs of a possible disability pension). However, it can take recourse against the person who caused the accident if he or she acted with gross negligence. Anyone who was driving under the influence of THC (example 3, possibly also example 2) must expect such a decision.

Costs: If someone has a serious accident and is no longer able to work, the costs are quickly in the range of 1 to 1.5 million francs. 20% of this is then 200,000 to 300,000 francs! If you are not very wealthy, you will probably have to pay off such an amount in monthly installments over your entire life.

Attention: The extremely low limit value of 1.5/2.14 µg/liter for driving a car can of course also be used by the IRM for other actions with accident consequences (e.g. operating heavy machinery). Thus, recourse for gross negligence could be possible in these cases as well. However, we have not yet seen any cases in this regard.