An alcohol interlock is a system comprising a breath alcohol measuring instrument and an immobiliser which may be easily installed in a motor vehicle. Before the vehicle can be started, a breath sample has to be provided to the alcohol interlock, normally through a mouthpiece. Once the breath alcohol measurement has been performed, the alcohol interlock will prevent drivers from starting the motor if they have an alcohol concentration above a predetermined limit value. This limit may be set at the legal limit of a respective country or lower.Alcohol interlocks that meet the relevant European Standards detect, for example, if the sample is delivered by a hum