When you are pulled over on suspicion of drunk driving, the officer will usually ask you to take a field sobriety test. This test includes a few different tasks that are used to determine whether you are showing signs of intoxication.

There are many different field sobriety tests that officers can conduct. The actual tests can have a direct impact on what happens to you from a legal standpoint. While these tests might seem like a good way to determine whether a driver is drunk, there are some limitations that are often called into question.

Not all tests are standardized

There is a huge misconception that all field sobriety tests are the same. Tests are actually categorized into two types. One is the standardized field sobriety test, which consists of the horizontal gaze nystagmus test, the one leg stand and the walk and turn. Any other tests fall into the second category, which is the non-standardized field sobriety test. This includes things like counting backwards or touching your nose with a finger while your eyes are closed.

The tests in the standardized battery are endorsed by the National Highway Traffic and Safety Administration. They reportedly have a success rate of determining impairment at least 91 percent of the time when performed together. This isn’t the case for tests that aren’t standardized, which is why the NHTSA only endorses the standardized versions.

Test controversy

The standardized field sobriety tests, and some of the non-standardized tests, might not be possible to complete for people with a physical or mental disability. People with brain injuries or physical disabilities, for example, may not be able to balance on one leg or walk and turn. They might have jerky eye movements, despite being fully sober, which could cause them to fail the horizontal gaze nystagmus test.

Even though a 91 percent success rate may seem high, the men and women who are falsely accused based on these tests could have a costly legal battle ahead. Think about this number: It means that nine out of every 100 people who take this test will have to fight criminal charges that they shouldn’t have to deal with.