After stopping drivers for traffic violations or after accidents, law enforcement officials in Arizona can request drivers to participate in field sobriety tests if the involvement of drugs or alcohol is suspected. These tests are precursors to determining actual inebriation but can be the first step toward a drunk driving arrest. Understanding these tests and their fallibility can be important for people who may face these situations.
Three different field sobriety tests are used and each one measures a different function per the National Highway Traffic Safety Administration. The tests are as follows:
- Horizontal Gaze Nystagmus test–When peoples’ eyes move to the far sides of their eye sockets, a natural amount of twitching is evidenced. This is called the Horizontal Gaze Nystagmus. When intoxicated, this twitching can become more pronounced and happen even sooner than when people are sober. In this test, officers move a small light which drivers are required to follow by only moving their eyes. If officers determine the amount of twitching near the eyes to be beyond normal, drivers could be at risk for further DUI testing.
- One-Leg Stand Test–This test measures drivers’ abilities to properly balance while standing on only one leg. Officers instruct drivers to stand on one leg for a period of 30 seconds and to count aloud during the entire time. The use of arms, swaying or hopping to aid balance can contribute to officers’ determinations of potential inebriation. The same is true for putting opposing feet down when balance on one leg is not possible.
- Walk-and-Turn Test–In this test, drivers must take nine steps along a straight line identified by officers and then walk back to the original starting position. They must position their feet in a strict heel-to-toe pattern the entire way. As with the one-legged stand test, loss of balance could be used to indicate impairment.
Field sobriety tests rely on the subjective decisions of the officers at the testing scenes. As noted by Patch.com, they may not always be accurate and drivers should be aware of this if they are charged with driving under the influence of alcohol.