EDIT:
The law is complicated on this topic and it varies by region. I didn’t think this needed saying when I made the post, but this isnt an end all be all on the topic, it’s just something I found interesting & posted it to c/Today I Learned.
Don’t take legal advice from a Lemmy post. Talk to a lawyer.
The Purpose of Portable Breath Tests
Portable breath tests are commonly used by law enforcement officers to quickly estimate a person’s blood alcohol content (BAC) at the scene of a suspected DUI offense. These handheld devices are designed to provide immediate results, helping officers in their decision-making process during a traffic stop or investigation.
It is essential to understand that a portable breath test is different from the more accurate breathalyzer devices used at police stations or during formal chemical testing. While portable breath tests can provide an initial indication of a person’s intoxication level, they should not be considered as wholly accurate or infallible.
https://rhilllaw.com/blog/2021/03/can-a-portable-breath-test-be-used-in-court/
In my jurisdiction that is exactly how they do it. No field sobriety test is used. Just roll down the window and blow. Refusal is the same penalty as a DUI and will earn a trip to the police station for the real test.
Interesting. Around here it comes as a nice little surprise after you parade around like a circus clown.