"Cognac alibi" as a drunk-driving defense and medico-legal challenge.

Some drivers with positive forensic ethanol analyses, offer an explanation that they consumed alcohol a short time before a traffic accident or after driving. In medico legal practice this is commonly known as hip-flask defense, but to us as "cognac alibi" defense. In these cases, the lawyers require the medico legal experts to offer as much information as possible so that the court may come to the most reliable conclusions about the driver's blood alcohol concentration at the moment of the traffic accident (BAC(Acc)). At the Institute of Forensic Medicine our own analytical approach was established to study this medico legal problem. It consists of three inter-related phases in which it combines the obtained BAC values, with testimonies of the drunk driving suspect andalso witnesses. A specific algorithm was designed for calculating absorption and elimination of consumed alcohol. All the above-mentioned elements and blood-ethanol values calculated according to Widmark's method were inserted into appropriate cells of MS Excel software in order to calculate BAC in the function of time. The result is a relevant analysis of the drunk driving suspect's BAC in 5-minute intervals, as well as a graphic representation in chart form.