Law enforcement officers can use a variety of tools to catch drunk drivers. Once an officer sees a driver who is likely impaired, the officer will usually pull the vehicle over.
After police officers or troopers communicate with the driver, they will make a determination about whether the person is impaired. This can include asking a driver to take a field sobriety test. Drivers should learn about these tests so they know what to expect during a drunk driving stop.
Standardized field sobriety tests vs. non-standardized tests
There are two types of field sobriety tests: standardized and non-standardized. The standardized test is a battery of three tests that have been approved by the National Highway Traffic Safety Administration. These three tests have been scientifically proven to be accurate.
The standardized field sobriety test consists of the walk-and-turn, the horizontal gaze nystagmus and the one-leg stand. The results of these three tests are admissible in court when they are performed according to set standards by an officer who has been trained to conduct the testing.
A non-standardized field sobriety test includes a measure that isn't part of the standardized test. The non-standardized test results are not admissible in court.
Accuracy of these tests
The standardized field sobriety test has been proven to be accurate in more than 90 percent of cases as long as it is performed by a person who is trained to conduct the test. This is one reason why they are admissible in court.
There are some factors that can impact test accuracy. Having to perform the tasks on an uneven surface can skew the result. Additionally, having to deal with oncoming cars with bright headlights can impact the results of the test. Some medical conditions, such as brain tumors, might also affect the results if the medical condition restricts coordination or other necessary skills.
Other factors may impact the non-standardized field sobriety tests. Since these tests include components that aren't standardized, the factors can vary greatly depending on the tests performed.
If you are facing drunk driving charges and field sobriety test results are being used against you, make sure you know what type of test was done. In some cases, your attorney may be able to call specific points of the test into question. It is essential to be prepared if you are planning to fight DUI/DWI charges in court.