Alcohol interlock in Belgium: when is it mandatory, what does it cost and how does it work?

The alcohol interlock (éthylotest antidémarrage) has existed in Belgium since 2010. For a long time, however, it was rarely imposed. The Act of 6 March 2018 on improving road safety changed that. Since then, the alcohol interlock has been mandatory in certain cases, and police courts (tribunaux de police) now impose it far more often. The rules are set out in article 37/1 of the Road Traffic Act (loi relative à la police de la circulation routière).

This article is part of our guide to drink driving. Do you drive a lorry, bus or taxi for work? Also read our article on the alcohol interlock for professional drivers.

How does an alcohol interlock work?

An alcohol interlock is a small device fitted in your car. It works like an immobiliser. Before you set off, you blow into the device. The engine only starts if your breath contains less than 0.09 mg/l of exhaled alveolar air (AAE) (0.2 per mille). During the journey, the device asks you at random moments to blow again. That way, nobody else can blow for you. You do not have to do it while driving: under the technical requirements, you have 15 minutes after the signal to stop safely and blow. If you switch off the engine within that time, you must still take the test. Every failed or missed test is recorded and shows up when the data is read out periodically.

An error message does not automatically lead to a report to the public prosecutor (parquet). If you can give a plausible explanation of what happened, the support organisation can accept it. For example: the device asked for a test when you had already got out and the car was still running. So always respond quickly, with supporting documents, if you are asked about an error message.

Code 69 is entered on your driving licence. During a check, the police can therefore see that you may only drive a vehicle fitted with an alcohol interlock.

When can or must the judge impose an alcohol interlock?

Optional

The judge may impose an alcohol interlock:

• for drunkenness or for refusing a breath test, breath analysis or blood test;
• for an alcohol concentration of at least 0.35 mg/l of exhaled alveolar air (0.8 per mille);
• for repeat offences at lower concentrations, for example when someone blows slightly positive several times in a short period.

The alcohol interlock is linked to alcohol. Were you driving under the influence of drugs or medication (in the law: a “similar state” to drunkenness) without a punishable alcohol level being measured? According to legal commentators, the judge cannot then impose an alcohol interlock. Other penalties exist for drugs: see our guide to drug driving.

In principle mandatory from 1.8 per mille

For a concentration of at least 1.8 grams of alcohol per litre of blood, or at least 0.78 mg/l of exhaled alveolar air (the breath analysis value), the judge must in principle impose an alcohol interlock. The judge may depart from this, but only with express reasons, based on the specific facts of the case. In practice, these are situations such as:

• the person shows that it was a one-off lapse, for example with blood values (gamma-GT, CDT) or a hair analysis that show no regular excessive drinking;
• the person is receiving support or treatment, with evidence to prove it.

If you want to argue for an exception, gather these documents before the hearing. A mere statement is not enough. Which tests do the courts accept today, and why are CDT and gamma-GT on their own often no longer enough? Read our article on the PEth test, hair analysis and blood values.

Always mandatory for repeat offences from 1.2 per mille

Anyone who is convicted again within three years, with at least 1.2 grams per litre of blood or at least 0.50 mg/l of exhaled alveolar air for each of the two offences, must receive an alcohol interlock (article 37/1, § 1, third paragraph). Here the judge has no discretion at all. The three-year period runs from the day the previous conviction became final (passé en force de chose jugée).

The repeat-offence rules also apply: a mandatory driving ban (déchéance du droit de conduire) of at least three, six or nine months and the obligation to pass four reinstatement exams (examens de réintégration). The ban and the exams come first. The alcohol interlock only follows afterwards. See also our article on repeat drink or drug driving.

Duration and conditions

• The alcohol interlock is imposed for at least one year and at most three years, or for life.
• It cannot be suspended.
• It cannot be combined with a permanent driving ban or with unfitness to drive under article 42. If there is doubt about your fitness to drive, that is examined first. See our article on unfitness to drive.
• The judge can exclude certain vehicle categories, but never the category with which the offence was committed, and only with express reasons. A lorry or bus driver who committed the offence in his or her own car can therefore ask for the alcohol interlock to be limited to the category B licence, since fitting a device in every one of the employer’s buses or lorries is unrealistic. In practice, judges are reluctant.

How much does an alcohol interlock cost?

An alcohol interlock is expensive, and all the costs are borne by you. The rates are indexed every year on 1 January. For 2026, the following amounts apply, including VAT:

Cost item	Amount (2026)
Support programme, first 12 months	EUR 1,200
Each additional 6-month period	EUR 125
Additional data read-out, for example after an error message	EUR 150 per read-out
Device: installation, read-outs and removal	about EUR 2,500 (1 year) to EUR 4,100 (3 years)
New driving licence with code 69	about EUR 25

An example: someone sentenced to 30 months with an alcohol interlock pays EUR 1,200 plus three times EUR 125 for the support programme, so EUR 1,575 in total. The device comes on top of that. For a one-year alcohol interlock, you therefore quickly reach about EUR 4,000, in addition to the fine and legal costs.

An important and often overlooked point: the judge can reduce the fine by the costs of the alcohol interlock and the support programme, in whole or in part (article 37/1, § 3). The fine cannot, however, go below EUR 1. The judge will not do this of his or her own accord. You or your lawyer must expressly ask for it.

The support programme

After the judgment, the public prosecutor’s office sends you a notification. The timing varies from one prosecutor’s office to another, and it often takes a few months. The notification states, among other things, the duration of the measure, the approved support organisations and service centres, the deadline for having the device installed and the address of the court registry where you must have your licence amended.

The programme is laid down in the Royal Decree of 26 November 2010 and includes:

• an introductory interview with an approved support organisation of your choice, within 14 days of the notification. If the judge has also imposed a driving ban of at least one month for the same vehicles, this deadline can be extended, provided everything is in order before you can drive again. Bring a copy of the notification. You receive a certificate that must always be kept in the car;
• a training session on using the device and on how alcohol is absorbed and eliminated;
• installation of the device by an approved service centre;
• read-out of the data: every two months in the first year, then every six months;
• a three-hour training course between the fourth and the eighth month;
• a final interview, after which the device is removed with the support organisation’s approval.

What if you do not comply with the conditions?

Do you drive a vehicle without an alcohol interlock, have someone else blow for you, disconnect the system or still drive after drinking? The support organisation reports it to the public prosecutor’s office. This is a separate offence (article 37/1, § 4). Besides a penalty, a driving ban then follows that is at least as long as the alcohol interlock period. Anyone who had three years with an alcohol interlock therefore risks at least three years without being allowed to drive.

The Court of Cassation has held that a conviction for failing to comply with the programme does not require the acts to have taken place on the public road (Cass. 13 November 2018, P.18.0509.N).

Is there an alternative?

You do not want an alcohol interlock, or you cannot afford one? You can choose not to drive during the period imposed. You then hand in your licence to the court registry. In practice, this amounts to a driving ban of the same length.

Frequently asked questions

Have your case reviewed

Are you facing an alcohol interlock? We look at which documents can support an exception or a limitation, and we ask the judge to deduct the costs from the fine. Contact us.

Law as at 30 September 2026. We update this article when the rules change.