Breath testFlanders
An introduction to the traffic rules and road signs of Flanders. Learn about driving, road safety and much more in our illustrated book, with answers to frequently asked questions.
For informational purposes only. Always follow official regulations. Some content and images were created with AI assistance.
250. Breath test
A breath test is a preliminary roadside test used to detect alcohol in a person’s breath and determine whether further testing is required. The person blows into a portable testing device, which compares the alcohol level with predefined thresholds. A breath test is generally used for screening rather than providing the final evidential measurement. If the result reaches the applicable limit, a more precise breath analysis or another legally recognised test may follow.
What is a breath test in Belgium?
A Belgian breath test is a preliminary alcohol test in which a person blows into an approved device that indicates the level of alcohol in the exhaled alveolar air relative to specified legal thresholds.
Does a Belgian breath test show the exact alcohol concentration?
Normally, no. The breath-test device indicates a result category based on legal thresholds rather than displaying the exact alcohol concentration used as the evidential result. The precise measurement is obtained by a breath analysis.
What results can an ordinary driver receive on a Belgian breath test?
For ordinary drivers, the device distinguishes between alcohol levels below 0.22 mg/l, from 0.22 mg/l to below 0.35 mg/l, and 0.35 mg/l or higher. These are represented by result codes such as S, A and P.

Traffic rules
Flanders