Voluntary Roadside Maneuvers
In virtually every DUI stop, one of the first things that the stopping officer will do is ask the driver to exit the car and submit to voluntary roadside maneuvers, also commonly referred to as field sobriety tests. There are three roadside tests that have been validated by the National Highway Traffic Safety Administration. In Colorado, police officers usually test DUI suspects on these three roadside maneuvers, sometimes adding a few other invalidated tests.
3 Steps of Roadside Maneuvers
First, there is the horizontal gaze nystagmus test, which consists of an officer asking the suspect to follow their finger or the tip of a pen with their eyes while keeping the head still. The officers are looking for twitching of the eyes, which can be an indicator of alcohol consumption (although there are many other causes for this jerking other than alcohol use). There are many requirements that officers need to follow in order to conduct an accurate HGN roadside sobriety test. Some of these DUI testing requirements are very specific distances between the objects being tested, asking about head injuries, and making sure there are no flashing lights in the DUI suspect's field of vision. If any of there requirements are not followed, or if you had nystagmus for a reason other than alcohol intoxication, the test is meaningless.
The second maneuver is the Walk and Turn, where the officer has the DUI suspect walk heel to toe in a straight line for 9 steps. This again has a very specific protocol that DUI officers must follow, or the test is not valid. Even obtaining a "failing" score on the test does not mean that the driver was under the influence of alcohol. There are many other reasons why someone might not perform perfectly.