What is a Sobriety Test?

Jessica Ellis

A sobriety test is used to check if a person is intoxicated or under the influence of drugs. These tests are often administered by law officers if drunk driving is suspected. Failing a sobriety test may result in drunk driving charges, which can carry penalties of fines, community service, or jail time.

Breathalyzers can be used as sobriety tests.
Breathalyzers can be used as sobriety tests.

Many sobriety tests measure coordination ability rather than actual blood alcohol content. These tests are often controversial, as most have a high rate of false positives and are based on the discretion of the test administrator, rather than on provable evidence. Sobriety tests may include performing physical tasks, such as walking in a straight line, standing on one leg, or following a light using only the eyes. While these tests are useful in winnowing out the severely inebriated, they can also trip up those who are naturally uncoordinated or nervous about the test.

Products such as mouthwash, which contains alcohol, may cause a false-positive on a sobriety test.
Products such as mouthwash, which contains alcohol, may cause a false-positive on a sobriety test.

A more accurate type of sobriety test uses a small device, often called a breathalyzer, to give an estimate of blood alcohol levels. Since many regions have alcohol laws based on blood alcohol content, these tests clearly indicate whether a person is over the legal limit. Breathalyzer tests require the user to blow air into the device, which then measure the amount of alcohol in the breath. It is important to remember that even if a person is under the legal allowed limit, any alcohol intake can lower coordination and motor responses, making accidents more likely.

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Those who fail a sobriety test may face arrest.
Those who fail a sobriety test may face arrest.

Despite the higher accuracy of a breath sobriety test, the device is not foolproof. Many models are extremely sensitive to temperature changes and can easily malfunction if not calibrated correctly. In addition, some substances, such as mouthwash, contain alcohol that can create a false positive on a breath sobriety test.

There is some controversy as to the use of a field sobriety test constituting an illegal search. According to some legal interpretations, a police officer must have probable cause to require a breath test or other sobriety test. If a person is pulled over and asked to take a test when he or she is following all road laws and has not been drinking, the person may try to refuse a sobriety test due to lack of probable cause. While this may result in them being arrested regardless, some legal experts suggest a person is within their rights to refuse a test when no probable cause exists.

For offenders who have been caught multiple times driving under the influence or violating other alcohol laws, certain steps may be taken to schedule regular sobriety tests. This includes the use of embedded sobriety devices in cars, which link the ignition to a breathalyzer device and will prevent the car from starting if a sobriety test is failed. The cost of the installation is typically paid for by the offender.

Police can administer a sobriety test if drunk driving is suspected.
Police can administer a sobriety test if drunk driving is suspected.

Discussion Comments


Sobriety tests do have their uses, but only a breathalyzer can say for sure if someone has been drinking, and if the person refuses to take a breathalyzer test in the field, and instead wants a blood or breath test administered at the police station, he or she is hoping by the time they get to the precinct, that the alcohol will have dissipated enough that they will be under the limit.

Blood tests are even better for someone like that. If they refuse the breath test and insist on a blood test, then getting a nurse or lab tech to draw the blood could take an hour, by which time the person may well be under the legal limit.


I've known one person who had to take a field sobriety test. She was sober, but had been taking cold medicine, and was dumb enough to drive. But this is the same chick who was throwing up drunk, but didn't want me to drive her car because I wasn't on her insurance! She wanted to drive anyway. I told her that her insurance company would be considerably more understanding if someone not on her insurance drove the car than if she had a wreck when she was drunk, or got picked up for DUI. We had a friend who actually sat on her in the back seat to keep her from getting up front and trying to drive.

Anyway, the cop gave her the breathalyzer, and of course, she blew a 0.0, but he still gave her a hard time about her driving. I'm afraid I was less than sympathetic when she told me.

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