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In Your Face? We Hope Not.

Permission to use photo granted by Intoximeters, Inc. The pictured device, the Alco-Sensor FST, is one of many mobile units approved by the National Highway Traffic Safety Administration as an “evidential breath alcohol measurement device."

This is an example of a handheld alcohol breath-testing instrument that police use for roadside tests of drivers they suspected of intoxication. In recent years, many handheld units (such as this one by Intoximeters, Inc.) have become accurate and reliable enough for their results to be admissible in court. Most jurisdictions, however, still use handheld units as screening tools that tell police which drivers to take to the station for further testing on larger, highly accurate desktop units.

Why test the breath for alcohol? When people drink more alcohol than the liver can break down at a given time, the leftover alcohol enters the bloodstream. The alcohol circulates and distributes itself evenly throughout the water in all the body’s tissues and fluids, including water vapor in the lungs. Thus, alcohol content in the breath parallels that in the blood.

The breath sensor converts the amount of alcohol in the breath to an equivalent blood alcohol concentration (BAC). BACs form the backbone of drunk driving laws. The legal BAC limit in all States is .08, a point at which driving skills are impaired in all drivers, regardless of age, gender, driving experience, or drinking history. Health policy research shows that basic drunk driving laws, including BAC limits and associated driver’s license removals, have resulted in a substantial reduction in alcohol-related traffic fatalities.

Sources:

National Highway Traffic Safety Administration. .08 BAC illegal per se level. (PDF, 201 KB)NHTSA Traffic Safety Facts: Laws. 2004 March:2(1).

National Highway Traffic Safety Administration. Highway safety programs; conforming products list of evidential breath alcohol measurement devices. A notice by the National Highway Traffic Safety Administration on 03/11/2010. Federal Register.

Voas RB, Fell JC. Preventing alcohol-related problems through health policy research.
(PDF, 693 KB) Alcohol Research & Health. Winter–Spring 2010:33(1–2):18–28.