Taking a field sobriety test sober may not be as easy as you think.  Each year police officers pull over thousands of people suspected of drinking and driving. But one defense attorney says you can easily flunk the test without having a drop to drink.

Flunking the test sober is what's called false positive. You can chalk it up to bad coordination, nerves or vertigo but there are reasons out there that make a field sobriety test less than 100 percent accurate.

Whether it's one drink or seven, you don't want to end up on the side of the road face to face with a cop.

The standardized field sobriety test is a battery of three tests - the horizontal gaze nystagmus, walk and turn, and one-leg stand - given to see if you are impaired. The horizontal gaze nystagmus test checks the involuntary jerking of the eye, which can be enhanced by alcohol. The walk-and-turn and one-leg stand tests require you to first listen to instructions and then perform the tasks. Both of those get harder to do with booze in your system.

Defense attorney André Hakes says the series of tests is full of flaws which begin with how the tests are given. “It’s very subjective,” she stated. "Administering something in a lab when you are testing something out is a lot different than administering it at 2 a.m., by the side of the road."

We put the field sobriety test to the test along the downtown mall. Three sober people willingly took the test administered by a Charlottesville police officer. While everyone passed, it wasn't with flying colors.

Holly Raatz had a balance issue on the walk-and-turn test. "If you didn't have good balance anyway, it's to your disadvantage,” she stated.

Erin Hughes didn't properly follow the instructions for the walk-and-turn test. She also messed up her alphabet when reciting it from "A" to "M." "It’s not that complicated, but I’m a mother of two and I’m sleep-deprived," she explained.

Grisha Kramer also stumbled on the alphabet test and had an issue with the one-leg stand. "I still have pretty solid balance and it was still a little bit hard," he said.

According to DUI DWI Foundation, the horizontal gaze nystagmus test has 77 percent accuracy. The walk-and-turn test is accurate 68 percent of the time and the one-leg stand test is the least accurate at 65 percent. 

Hakes stated, "I absolutely have had cases where someone has failed the field sobriety tests, been arrested for DUI and then been acquitted."

It's for that reason Hakes says you should politely decline to take the field sobriety test. Legally you can refuse it without consequences. Hakes says the best thing to do when you are pulled over is to be quite and not offer the officer any additional evidence against you.

Lieutenant Ronnie Roberts with the Charlottesville Police Department says officers are repeatedly trained on how to administer the field sobriety test so they can tell the difference between those who have been drinking and those who may just be nervous.

"It enhances their recognition of the impaired driver and those signs and symptoms that we see at roadside,” he said. “The bottom line is don't drink and drive."