Use of breath test as evidence. Comparison between bracs and bacs in a driving population

This work compares the results of roadside use of the breathalyser test with those from contemporary blood samples, carried out within the framework of a program of weekend night-time checks on drivers. Italian law requires the police to use breathalysers as the only instrument for screening and confirming a state of intoxication due to ethyl alcohol intake in drivers. Analysis, which is used as evidence, is carried out on the roadside by means of instrumentation run off a car engine. Current Italian legislation does not require the use of confirmatory analyses carried out on blood samples or expired air in standard environmental conditions, as is the case in other countries. Drivers are considered to be in a state of drunkenness if their BAC, extrapolated from analysis of expired air with a conversion factor of 2300:1, is greater than or equal to 80 mg/100 mL in two successive measurements, the second being made 5 minutes after the first. With the aim of verifying in situ the suitability of the procedure and the instruments used, a comparison was made between results obtained at the roadside using the breathalyser and those on venous blood samples taken at the same time. This research formed part of a program of night-time checks on drivers in the Veneto Region on weekend nights in the period l997-1999. For the covering abstract see ITRD E106992.