A police officer does not need to give you a breath test or a blood test to arrest you for driving under the influence. If they have reasonable suspicion to make a stop, they can put you through field sobriety tests. If you fail those tests, they can then arrest you and you may face DUI charges.

This implies that the tests must be pretty accurate, getting it right almost 100% of the time. Otherwise, the officers would theoretically be arresting a lot of sober drivers. But is that how it works?

It’s not. When the tests first started being used, they were once tracked to an abysmal accuracy rate of 47%. This meant that in more than half of the cases, police got it wrong in one direction or another.

Obviously, that was a problem. The result was a program that uses three main tests, standardizing the process so that officers could be more accurate. This did bring the rate up, but only to 82%. Police officers were still getting it wrong in roughly one out of five cases. The tests — and their accuracy rates on their own — are as follows:

  • The one-leg stand test: 65%
  • The walk and turn test: 68%
  • The horizontal gaze nystagmus test: 77%

If you have been arrested after failing the tests, looking at these numbers is probably fairly concerning. Did the officer really have any idea if you were intoxicated or not? Was your driving impaired, or did the officer’s opinion spur the arrest, outside of any evidence? These are definitely questions worth asking. Having an experienced attorney on your side can help ensure that your rights are protected if you’re facing DUI charges.