Drink Driving in Spain: Margins of Error in Breathalyser Tests
While the penalty for drink driving in Spain can lead to imprisonment, in practice (first offence, no criminal record) this is very unlikely.

Punishments available to the Courts
Article 379.2 of the Spanish Criminal Code states that anyone who drives a motor vehicle under the influence of toxic drugs, narcotics, psychotropic substances or alcoholic drinks shall be punished with a sentence of imprisonment for a period of between three to six months or with a fine for six to twelve months (at the specified daily rate).
Alternatively, drink driving in Spain may be punished by community service orders for 31 to 90 days and, in any case, with disqualification from driving motor vehicles for more than one year up to four years.
In any case, anyone will be punished if the result of a breathalyser test shows an ‘exhaled alcohol level’ of more than 0.60 milligrams per litre or an alcohol level greater than 1.2 grams per litre blood.
Different Types of Breathalyser
There are two types of breathalyser used by the police in Spain – one is a mobile design, used by the Police when out on patrol.
It is more rudimentary and less precise than the larger version that is used in Police Stations. This latter version is the definitive breathalyser and it is the results on this machine that are used to determine what action, if any, should be taken against a motorist.
So, in order for there to be a conviction for drink driving in Spain, the latter test must be carried-out. At this point is is worthwhile pointing out that the driver must submit to this test as a refusal will be considered a crime of disobedience.
Margin of Error
To the result obtained from a breathalyzer test we must apply a margin of error which will, therefore, reduce the result – this can be calculated by performing a simple arithmetic operation.
If after applying margins of error, if the first test yields a rate greater than 0.65 mg Alcohol/litre breath but the second measurement result is lower, the police will prepare and submit a report to the judicial authorities that a crime has been committed because the driver, when tested, was driving, according to the primary test, with a rate higher than the rate provided for in Article 379.2, which will result in a fine only.
On the contrary, if after applying the above margins of error to the first test, the result is a reading of less than 0.65 mg of ethanol per liter of exhaled air and that reading is higher than the second reading, only an administrative complaint shall be made for such a breach.
In the interests of the accused and to guarantee the exclusion of any incorrect results, the legal limit has to be exceeded by both results because, otherwise, a person could be condemned although they had not in fact exceeded the legal maximum.