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How accurate are field sobriety tests?

On Behalf of | Apr 23, 2019 | Drunk Driving |

On your way home from an evening out with friends, you suddenly see flashing red and blue lights behind you. Nervous, you pull over as the police officer approaches your vehicle. You are asked to step out of your vehicle and perform several roadside tests. You wonder whether you have a choice and how accurate these tests will be.

Field sobriety tests have long been disputed for how accurately they can determine a driver’s level of intoxication. As part of the traffic stop for suspected drunk drivers, Georgia drivers may find themselves debating whether to comply with the requests of the officer to participate in roadside tests.

The standardized field sobriety tests

Dating back to the 1970s, the National Highway Traffic Safety Administration (NHTSA) asked the Southern California Research Institute (SCRI) to evaluate dozens of field sobriety tests. The SCRI reported that the following standardized tests are most accurate in determining blood alcohol content (BAC) levels:

  • The horizontal gaze nystagmus test. Officers watch for the jerking of eyes when asking you to watch a small moving object without moving your head.
  • The walk and turn test. Officers test for both balance issues and problems following directions when asking you to walk heel-to-toe before pivoting.
  • The one-leg test. Officers watch for balance issues in this test, which requires you to lift one foot six inches off the ground with your hands to the side.

However, these tests do not produce consistently accurate results. According to, the accuracy rates of the horizontal gaze nystagmus test, the walk and turn test and the one-leg test are 77%, 68% and 65%, respectively. When used together, the tests produce correct results 82% of the time.

Complications of field sobriety test results

While a perfectly healthy and sober person may fail these tests, other complications can lead to misleading results. For the walk and turn test and one-leg test, age, weight, shoes or even back problems can cause you to fail the test. For the horizontal gaze nystagmus test, various medical and eye issues can lead to the failure of the test.

While refusing field sobriety tests is both within your rights and could lead to less evidence of intoxication, this could also be used against you when facing criminal charges. With the disputed accuracy of tests and various complications, drivers should seriously weigh the benefits of taking the tests.