The police have several tools at their disposal to test whether a driver is drunk.
One of the more common and basic methods of checking drivers’ inebriation levels is standardized field sobriety tests. Unlike a chemical test, like a Breathalyzer, these tests require no special equipment and are largely subjective. Here are the kinds in use:
Horizontal gaze nystagmus test
The horizontal gaze nystagmus test involves having the driver focus on an object, such as a finger, pen or light and follow it with their eyes alone. The officer will then move the object from side to side. In doing so, the officer is looking to see if the driver is struggling to follow the object or if their eyes are jerking. Drivers who are intoxicated often have a harder time preventing their eyes from jerking at extreme peripheral angles.
The walk-and-turn test has the driver walk nine steps out, heel-to-toe, on a straight line and return to where they started. There are several indications that a driver may be intoxicated, such as loss of balance, the inability to follow instructions or taking too many or too few steps.
One-legged stand test
As the name suggests, the one-legged stand test has the driver stand on one leg. The driver may have their foot off the ground by six inches and stand like that for about thirty seconds. During this time, the officer will look for signs of inebriation, like hopping, putting their foot down early or swaying.
Non-standardized field sobriety tests
The above are all considered standard field sobriety tests. However, the police may also ask drivers to do non-standard field sobriety tests. These tests are often made up and could have the driver listing the alphabet backward or touching their nose, for example.
Standardized and non-standardized field sobriety tests are often highly inaccurate. Drivers may need to be aware of their legal rights to ensure they don’t face a DUI charge.