If you’ve been pulled over and the officer suspects that you’re driving under the influence in Louisiana, there’s the possibility that you’ll be asked to take an alcohol breath test. But how accurate are these tests, really?
Can you trust an alcohol breath test?
You might know them as breathalyzers. It’s the most common method of measuring BAC – blood alcohol content – because it’s a fast and easy way for law enforcement to gauge your level of intoxication. Using an alcohol breath test is simple – even a drunk person can do it.
The BAC legal limit for driving is 0.08%. As a federal standard, it’s the same across the United States. And when a police officer administers a breathalyzer test, it’s admissible evidence in court. Keep in mind that if you have a higher alcohol tolerance, there’s a good chance that you won’t feel as intoxicated as your BAC seems to indicate you are.
There are at-home tests available, providing a way of checking your intoxication level before getting behind the wheel. But be wary: These versions have been shown to be less reliable. This may sometimes be due to operator error, but there have been many reported cases in which the device itself was to blame.
How does an alcohol breath test work?
The breathalyzer consists of two chambers, a meter and a mouthpiece. The chambers are full of liquid, one of which is a chemical cocktail including potassium dichromate. This starts out with a red-orange hue, but if alcohol is introduced to the solution, it turns green – a different shade depending on the amount of alcohol.
Breathalyzers also include a photocell, which is a sensor that reacts to light exposure. By comparing the color of the liquid before and after the test, it can calculate the BAC into a numeric value.