The two most common ways police officers determine if a driver is impaired are breath tests and field sobriety tests. There are portable breath tests that police officers can carry with them, but these often can’t be used in court, so they need to bring the individual to do a breathalyzer at the station.
As such, officers who have pulled someone over will often rely on field sobriety tests. These do not prove impairment, but they may give the officer enough reason to conduct an arrest. This can lead to the breath test, which provides more evidence of whether or not the person has been consuming alcohol.
Why accuracy matters
What this means is that it’s very important for those field sobriety tests to be accurate so that individuals who are not impaired are not constantly being arrested based on failing these tests. Unfortunately, studies have found the tests are not that accurate.
For instance, some reports say that all three main tests – the stand and turn, the horizontal nystagmus, and the walk-and-turn – only get it right in 91% of cases, and that’s when they’re all used together. If only one test is conducted, it’s even less accurate than that. You also have to consider factors like bias by the police officer, whether or not they were trained to conduct the tests and whether they made any mistakes. Any error like this can make it even less reliable.
If you end up facing charges for drunk driving, you need to know the role these tests played and the legal options you have.