DWI enforcement in St. Louis, Missouri, has come to rely increasingly on the estimated Blood Alcohol Concentration (BAC) number produced by an aging technology. The Alco-Sensor IV (ASIV), manufactured by Intoximeters, is a portable breathalyzer device used by police officers to test driver’s the police suspect are intoxicated. At 1/3 the price of other evidentiary devices, police departments love the ASIV. The other advantage St. Louis area police find in the ASIV is that it is portable. All other evidentiary breath testing devices in the state are rather large and must generally be used at the police station.
Preliminary Breath Testing devices (PBTs) are small portable devices commonly used by police in Missouri to check whether a driver is positive or negative for alcohol. The devices are not considered accurate enough to be used in court against a driver/defendant. The ASIV uses the same technology as PBTs which are used throughout the state. It is, in simple form, a PBT with a printer attached.
Why would the state use a technology they do not consider reliable to give accurate BAC results, attach a printer, and approve it for use with one manufacturer? Whatever the reason, Missouri approved the use of the ASIV as an evidentiary breath testing device. It is now one of the most commonly used breath testing devices in the state. After the state legislature defunded consitutionally suspect DWI checkpoints, the Missouri State Highway Patrol has begun conducting more “saturation patrols”, where troopers who call themselves “the wolf pack” try to write as many DWI’s as possible in a given night. What device do they normally use to measure BAC? The least accurate device that can be used under Missouri law- the ASIV.
The ASIV is 1/3 the price of other devices. It is outdated technology that came into use in the mid-1990’s. Approximately 185 are in operation throughout Missouri and the St. Louis area. There is no slope detector in the device. There are no mouth alcohol filters in the device. It has more potential to give incorrect BAC readings for drivers than any other evidentiary device used in Missouri. If you are stopped for DWI, call a lawyer before you decide whether or not to provide a breath sample.
