A traffic stop can happen when the police have reasonable suspicion that a driver is drunk, such as swerving or running traffic lights. To perform an arrest, the police may still need to have probable cause that the driver is drunk. Probable cause is actual evidence of a crime.
To have probable cause, the police often have to gather evidence against a driver. Here’s how they do that:
Asking drivers questions
Law enforcement often begins collecting evidence by asking drivers questions. These questions may relate to if the driver was drinking, how many drinks they had, where they are driving from or if they have any open bottles of alcohol in their vehicles. Drivers can answer these questions, but many innocent people have faced charges, fines and incarceration because something they said made it seem they were involved in criminal activity. Drivers can plead the Fifth to avoid answering any questions.
Conducting field sobriety tests
A field sobriety test is a physical examination judged by the police. The police could, for example, ask drivers to do the following standardized field sobriety tests: one-legged stand, walk-and-turn test or horizontal gaze nystagmus test. Drivers may also be asked to do non-standardized tests, such as touching their nose or reciting the alphabet backward. These tests may help the police spot signs of inebriation.
Using chemical sobriety tests
The most accurate way to assess a driver’s condition is by having them take chemical sobriety tests. There are three kinds of chemical sobriety tests: urine, blood and breath. Each of these tests evaluates a driver’s blood alcohol content (BAC), which is the amount of alcohol found in the body. While blood tests are often the most accurate of the three, breath tests are often readily accessible and fast.
It’s important to remember that evidence can often be challenged. Mistakes can be made with the way tests are run, and evidence is sometimes gathered illegally. People facing DUI charges may need to learn about their legal defense options.