The results of blood alcohol tests—commonly administered via breathalyzers—often mean the difference between jail sentences and freedom for drivers who are pulled over for allegedly driving under the influence.
These tests, however, may sometimes malfunction. According to a press release in the San Francisco Chronicle, a few cities in the Bay Area recently reviewed hundreds of DUI cases that involved the use of faulty breathalyzers.
Some observers believe that the problem with breathalyzers extends beyond a few faulty machines. In fact, the fundamental technology and interpretation of breathalyzer results may have flaws, as well.
First, there is the threat of condensation. These blood alcohol testing machines are used more than once, and some critics claim that the breath of one person may remain on the machine until it is used by someone else.
Unless a test is given that can be used once and only once, this problem is likely to remain.
In addition, breathalyzers test for a number of different chemicals in the body, rather than just alcohol. Some people claim this broad scope may skew the alcohol-related results.
Third, the blood alcohol testers are designed to study the “average” person. If someone falls outside the average range—for example, if a person is very small or unusually large—the machine might find that person intoxicated even though he or she is able to pass field sobriety tests.
Fourth, breathalyzers have faced criticism because of the machine’s built-in margins of error. Most prosecuting attorneys will admit that the tests have margins of error of about .01 percent.
While this may seem like a minor defect, the legal blood alcohol limit is only .08. Thus, if someone has a .07 blood alcohol level, a potential breathalyzer error could have drastic consequences.
Moreover, the same machine often provides different testing results for the same person within just a few minutes. In order for breathalyzer results to be admissible as evidence, police officers must get a suspect to blow two different readings within .02 percent of each other.
Again, this seems like a relatively small difference, but DUI arrests are often determined by fractions of a percent.
In addition, margins of error not only decide the line between driving under the influence and legal driving, they may also determine whether a person has committed a misdemeanor offense or a more serious DUI crime – which may increase the penalties from a mere fine to a prison sentence.
While breathalyzers are not perfect, they do provide an efficient, objective means for police officers to determine the level of a driver’s intoxication.
Until a more reliable method of measuring intoxication is discovered, breathalyzer tests are likely here to stay.