[owenmarshall]

> Sorta related: What is the current situation regarding testing for being actively under the influence of marijuana? For better or worse, breathalyzer tests have been generally accepted for testing being actively under the influence of alcohol. Are breathalyzer tests used for marijuana, too? Or, is it just a field sobriety test?

A quick and very important slight tangent that there are two kinds of breath tests at play.

When the police pull someone over for suspicion of DUI, they're attempting to establish probable cause for an arrest. The preliminary breath test is one of these tools, and in most (possibly all?) states it is voluntary & not admissible as evidence. You can look your own state's laws up, but here's a deep dive from Wisconsin on their laws[1].

If the police establish probable cause of intoxication because you volunteered to take a field sobriety test / preliminary breath test, because of their description of your physical condition (bloodshot/glassy eyes) or circumstances (open container, scent of marijuana), you'll be arrested & compelled to perform an evidentiary breath test on a stationary machine in a police station, or provide a blood sample to test for intoxication. And this is not a voluntary test – your refusal to provide an evidentiary test is considered evidence that you committed a DUI and you will be penalized accordingly.

So in general: it's almost best to keep your interactions with the police limited & refuse any voluntary tests to prevent probable cause from being built.

[1]: https://www.wisbar.org/NewsPublications/WisconsinLawyer/Page...