How long after drinking a half pint will an Interlock detect alcohol?

It is impossible to predict exactly how long after drinking a half pint an Interlock system will detect alcohol. There are a number of factors that can affect this, including the person's weight, age, gender, metabolism, and the type of alcohol consumed. Additionally, the sensitivity of the Interlock system can vary. As a general rule, however, it is best to wait at least 30 minutes after drinking alcohol before attempting to start a vehicle with an Interlock system installed.