A breathalyzer has measurements ranging from 0.1 grams up to 0.50. When a driver is stopped, they are asked to step out of the vehicle and stand straight.
The traffic officer inserts a new tube into the breathalyzer, and the driver is asked to blow into it and thereafter the breathalyzer makes three spontaneous sounds.
At that point, the police officer checks the level of alcohol and if it indicates 0.18 gram the driver is considered too drunk to be driving.
The drunken driver is then given a legal punishment, usually a fine of not more than Rwf25,000 or imprisonment for 7 days to 6 months.