How Reliable are Field Sobriety Tests?

Field sobriety tests are used by police primarily to make a DUI "arrest decision", but they are often inaccurate.

We've all heard about field sobriety tests and seen them performed on countess TV cop shows. On TV, they are used to prove someone is too inebriated to drive. But what do they mean in real life?

In real life, police officers use the standard field tests to make an "arrest decision," not to scientifically determine if someone is over the limit. If a driver "passes" these tests, the results show the officer the person hasn't had too much to drink. If a driver "fails," the officer knows it's time to give the driver a breath test. Most of the time, even if a driver doesn't blow over the limit of 0.08% BAC, the officer will still arrest the driver based on the fact that he or she "failed" a field test.

How reliable are these tests?

According to many separate studies, these tests are not reliable at all. The newest studies prove that officers are terrible at using the tests to determine if someone has had too much to drink. This is despite training and despite years of experience, most officers find these tests difficult to use in the way we expect them to be used. They are easy your average driver to fail yet at the same time, easy for seasoned alcoholics to pass.

One reason for this of course, is that .08% BAC isn't a magic number. Not everyone who is at or a little above .08% show the signs a really intoxicated person normally shows. A BAC of .08% is fairly low, and these tests simply don't work particularly well at such low levels. Physical dexterity tests such as the finger to nose test, slurred speech and the one-leg stand tests have been shown not to be useful until a the driver is at about .15%. That is someone who's had a serious amount to drink.

What can you do about it?

A good DUI lawyer knows this and will challenge any field tests their client may have performed.

For more information on hiring an attorney for a DUI charge, see Getting Help for a DUI Charge.