"Drinking and driving: there are stupider things, but it's a very short list."
Author unknown
In 1954 Robert Borkenstein (1912-2002), of the Indiana State Police, invented the breathalzyer, a portable device that provided scientific evidence of alcohol intoxication. After the consumption of alcohol, blood flows through the lungs and some of the alcohol evaporates and moves across the membranes into the air sacs. The breathalyzer shows a direct relationship between the concentration of alcohol found in the air sacs and that in blood. Subjects blow up a balloon (ensuring a deep air lurag sample is taken), the contents of which are released over a chemical solution, resulting in a color change detected by a monochromatic light beam. The extent of the color change relates to the percentage of alcohol in the breath.
The breathalyzer replaced the drunk-o-meter, an earlier device developed by Rolla Harger and patented in 1936. It relied on the sampled breath being analyzed in specialist laboratories. Prior to this, police had to rely on observation of a suspect's physical condition, evidence that did not stand up well in court. The breathalyzer met the demands of legal evidence, although there were criticisms that the results varied between individuals consuming identical amounts of alcohol due to gender, weight, and metabolic rates.
In 1964, Borkenstein published a milestone study in which he argued that the 0.08 percent blood- alcohol content should be the standard, above which any driver should be considered impaired.
By the mid-1980s, chemical-based devices had given way to infrared technology where a narrow band of infrared light, of a frequency that is absorbed by alcohol, is passed through a breath sample. How much of the light makes it through to the other side of the sample without being absorbed gives the precise concentration of alcohol.
